Index of "1995 1995 Interim Report on Climate Change Country Studies" ||
Index of "Environment and Science" ||
Electronic Research Collections Index ||
U.S. Department of State
March 1995 Interim Report on Climate Change Country Studies
Oceans and International Environmental & Scientific Affairs
[SECTION 4 OF 4]
Editor's Note: Numbers and letters contained withtin "<" and ">" marks
represent subtext in scientific formulas. Numbers between
"/" and "/" represent footnotes. Footnotes by the names of authors
are located just beneath the names. Footnotes contained within the
text can be found at the end of each chapter.
Mongolia: Preliminary 1990 Greenhouse
D. Dagvadorj and M. Munkh-tsetseg,
Hydrometeorological Research Institute,
Ministry for Nature and the Environment, Mongolia
SUMMARY: Mongolia is the 35th country to have ratified the United
Nation's Framework Convention to Climate Change (UNFCCC). One of
the commitments accepted by the country is the submission of a
national greenhouse gas (GHG) inventory to the world society.
At the end of 1993, Mongolia joined the U.S. Country Studies Program
and has begun to compile its national GHG inventory. We have used
IPCC methods for estimation of this inventory. We prepared initial
estimates of anothropogenic emissions of GHG in Mongolia for 1990.
Due to the lack of data necessary for calculations, these
estimations are not complete and we continue with our efforts to
make them more precise. Mongolia's national GHG inventory comprises
emissions of gases such as carbon dioxide (CO<2>), methane (CH<4>),
nitrogen oxides (NO), and carbon monoxide (CO) from five main
sectors.: Energy, Industry, Agriculture, Land-Use Change and
Forestry, and Waste. It was estimated that in 1990 emissions from
the abovementioned sectors totalled 19,524 Gg carbon dioxide,
330.1Gg methane, 0.9 Gg nitrogen oxides, and 83.3 Gg carbon
monoxide (Table 1).
In this report, Mongolia presents its atmospheric emissions inventory
for the first time. The initial version of the inventory was carried
out at the Hydrometeorological Research Institute, Ministry of Nature
and Environment, for 1990. We followed the IPCC inventory guidelines
The inventory includes emissions of carbon dioxide,
methane, nitrogen oxides, and carbon monoxide. Following the
IPCC Guidelines, the inventory reports emissions from five
sectors: Energy, Industrial Processes, Agriculture, Land-Use
Change and Forestry, and Waste. Due to the historical,
geographical, climatic and economic characteristics of the
country, some sources of GHG, such as oil and gas systems,
savanna and agricultural residues burning, rice cultivation, and
forest clearing, do not apply to Mongolia. Emissions from
fuel combustion for power generation and conversion of
grasslands to arable land are the largest sources of carbon
dioxide. A significant amount of methane is emitted by
We followed the IPCC inventory guidelines. The lack of
data necessary for calculations was the main obstacle for
us. Basically it was possible to obtain only general statistics
such as fuel consumption, cement production, domestic
animal population, area of cultivated land, etc. (Statistical
Yearbook, 1992, 1994). Country-specific emission factors of
gases were not developed in Mongolia.
Data collection was the most difficult for the Forestry and
Waste sectors. Where necessary, we have used default IPCC values
given in the Greenhouse Gas Inventory Workbook. We would like to
note that these default data were very helpful in carrying out
The 1990 greenhouse gas emissions highlights are presented
in Table 1. These results are preliminary and may be changed as
more precise data become available. The sectoral distribution
for both carbon dioxide and methane emissions is shown on
Figures 1 and 2. Both Figures are derived from Table 1.
The Energy sector is the largest contributor to GHG emissions
in Mongolia. Activities in this sector cover coal production
(mining and post-mining activities such as transportation and
storage), fuel combustion at the thermal power stations, and
coal and biomass combustion in private houses (ovens) for
The main type of fossil fuel used in Mongolia is coal.
Natural gas and oil are not produced in Mongolia and are not
imported. Coal is burned mainly at the power stations and in
less quantities in private small dwellings. Oil products
(kerosene, gasoline, etc.) are imported and used for
transportation and power stations. Combustion of these fuels is
the greatest source of carbon dioxide emitted into the
Biomass in Mongolia is burned in cook-stoves only.
Other activities like agricultural residues burning and on-site
burning of cleared forest are not applicable in Mongolia.
Biomass burning is the only significant source of nitrogen
oxides and carbon monoxide according to our calculations.
Emissions from the transportation sector have not been estimated
yet. The only significant methane source for the energy sector
is coal mining and post-mining activities. However, these
emissions are relatively insignificant compared to methane
emissions from agriculture.
Following the IPCC Guidelines, cement production is included
into the industrial processes sector (IPCC, 1993). Cement
production emission estimates are presented in Table 1. Although
heavy industry is not developed sufficiently in Mongolia, mining
is the basis of the national economy. Unfortunately, until now,
we do not have a methodology to calculate emissions from
other industrial processes.
Emissions of methane from enteric fermentation and
anaerobic decomposition of manure of domestic animals are the
primary GHG emissions from agriculture. Other sources of GHG
such as rice cultivation and savanna burning included in the
IPCC Guidelines are not applicable for Mongolia. This is due to
the geographical location of the country. Open burning of
agricultural residues are not a significant source. Since 1990
agricultural residues are used completely for livestock needs.
Emissions from livestock account for 91 percent of all methane
emissions, which was 330.1 Gg of methane in 1990. The livestock
population is relatively large (26.3 m heads, including swine
and poultry at the 1990 level) (Statistical Yearbook, 1992).
Historically, Mongolia is a country of nomads and
livestock breeding is the traditional form of lifestyle instead
of farms. A very insignificant part of the livestock population
(farming cows, swine, and poultry) is raised on farms. Thus,
anaerobic decomposition of manure is not a large source for
Mongolia, especially due to the dry boreal climate conditions.
This is a source of uncertainty in the emission estimates.
Land-Use Change and Forestry
The IPCC Guidelines describe four potential sources for
this sector: forest clearing, conversion of grasslands into
cultivated land, abandonment of managed lands, and managed
forests. Mongolia's inventory includes emissions and uptake of
GHG from two of these sources: conversion of grasslands to
cultivated land, and managed forests. Forests cover about 8-10
percent of the territory of the country and forest clearing
The estimates of emissions from managed forests are preliminary
and will be refined as more data become available.
The tradition of land cultivation in Mongolia is not very
long. Mongolia began to cultivate considerable land area only
after 1958. More recently, some cultivated land has been
abandoned. We have estimated the area of abandoned lands, but do
not have relevant information (annual rate of aboveground
biomass uptake and rate of uptake in soils) since default values
were not available. In this way, it was not possible to
calculate carbon dioxide uptake of this sink.
Under the IPCC Guidelines, we have estimated that conversion
of grasslands to cultivated land is the second largest emission source
of carbon dioxide for Mongolia, accounting for up to 36.8 percent of
CO<2> emissions. In our view, this estimate is too high due to the use
of a default coefficient of soil carbon content of grasslands for
temperate regions which is 70 ton per hectare. We estimate that
1,400 kha of grasslands have been converted from 1958 to 1990
(Statistical Yearbook, 1994).
Waste management activities generate methane, produced
from anaerobic bacterial decomposition of organic matter in
landfills, industrial and municipal wastewater. We estimated
emissions from this sector as 14.5 Gg of methane, which is 4.4
percent of all methane emissions. We used the default values
provided in the IPCC Guidelines.
This article is an overview of the first version of the 1990 National
Greenhouse Gas Inventory of Mongolia. Therefore, the results presented
here are preliminary and will be revised as more detailed estimations
are made. One of the main problems we faced was the lack of data on
emission factors and activity levels suitable for Mongolia. We have used
IPCC default values in many cases. However, in some cases default values
were not available. This lack of data is a significant source of
uncertainty and bias for the emissions estimate. For example, carbon
dioxide emissions from land-use change and forestry from 1990 may
be too high.
These preliminary results show that we need more detailed
information for all sectors to produce more reliable results.
IPCC/OECD Joint Programme. 1993. IPCC Draft Guidelines
for National Greenhouse Gas Inventories. Vol.1.
Greenhouse Gas Inventory Reporting Instructions.
IPCC/OECD Joint Programme. 1993. IPCC Draft Guidelines
for National Greenhouse Gas Inventories. Vol.2.
Greenhouse Gas Inventory Workbook.
IPCC/OECD Joint Programme. 1993. IPCC Draft Guidelines
for National Greenhouse Gas Inventories. Vol.3.
Greenhouse Gas Inventory Reference Manual.
Statistical Office of Mongolia. 1992. Mongolian
Economy in 1991. Statistical Yearbook.
Statistical Office of Mongolia. 1994. Mongolian Economy
and Society in 1993. Statistical Yearbook.
Peru: Emissions Inventory for Energy
and Nonenergy Sources
Jorge Ruiz Botto, Jorge Ponce Urquiza, Cesar Picarro Castro,
Juan Avila Lopez, Ivan Llamas Montoya, Elizabeth Culqui Diaz
Universidad Nacional de Ingenieria (UNI), (Facultad de
Ingenieria Ambiental) and Instituto Peruano de Energia Nuclear (IPEN),
Servicio de Meteorologia e Hidrologia (SENAMHI)
SUMMARY: To carry out the greenhouse gas emissions inventory in
Peru, the emission system was divided into two major sectors:
Energy and Nonenergy. The basic IPCC methodology was used in
preparing the inventory. Due to the lack of national emission
factors, this generally included the use of the IPCC emission
factors (default values). Some local emission factors were available
and used in the Nonenergy Sector. Emissions in the Energy Sector
were as follows: CO<2>, from all sources totalled 35,174 Gg
(16,246 Gg from biomass) using the IPCC "top-down" approach;
CH<4>, from biomass, coal production, and oil and gas systems
totalled 69.59 Gg; NO from biomass totalled 622.71 Gg; CO from
biomass totalled 0.464 Gg; and N<2>O from biomass totalled 10.94 Gg.
Emissions in the Nonenery Sector were as follows: CO<2>, 58,313 Gg;
CH<4> 1,204 Gg; N<2>), 6.19 Gg; and CO 10,849 Gg.
The quantification of Peru's Greenhouse Gas National Inventory
is a complex task carried out by professionals and students
of several institutions and universities in the country. To
carry the work out in a systematic and methodological manner,
work groups were formed with the participation of professional
national staff and researchers of the National University of
Engineering (UNI), the Peruvian Institute of Nuclear Energy (IPEN),
and the National Service of Meteorology and Hydrology (SENAMHI).
The National Greenhouse Inventory was carried out in accordance with
the methodology developed by the Intergovernmental Panel on Climate
Change (IPCC) and the Organization for Economic Cooperation and
Development (OECD). The guidelines and software (MINERG) provided by
these institutions facilitated the planning and implementation of the
National Inventory of Greenhouse Gases for l990.
Development of the national inventory included the following tasks:
-- Collecting and validating source data
-- Research on technical parameters such as emission factors,
carbon storage rates, the fraction of fuels not oxidized
-- Application of the tables and worksheets established in
the IPCC methodology
-- Processing and analysis of information
-- Use of the IPCC software (MINERG) to check the results obtained
-- Preparation of quarterly reports
Using the methodology mentioned above, Peru's inventory for
the energy sector is summarized in Tables 1-7.
Results for emissions of CO<2> from energy sources for
specific fuels using the IPCC (top-down) methodology are given
in Table 1.
For comparative purposes and to lay the groundwork for future
identification of mitigation policies, energy consumption and emissions
were also estimated by sector. The results of the CO<2> emissions from
energy sources for specific fuels using this "bottom-up" approach are
given in Table 2.
In order to obtain information on fuel consumption in
each economic sector, it was necessary to recalculate the
National Energy Balance for 1990, using information from
qualified institutions and organizations, and consolidating
these data in a main information source called Actualized Energy
Balance--1990. Using the Actualized Energy Balance, there is a 2
percent of difference between the calculations of CO<2> from
energy sources obtained in the "top-down" and "bottom-up"
approach. This difference is due to "adjustments" (statistical
tools used to make compatible the data corresponding to
different information sources such as the National Council of
Energy of the Ministry of Energy and Mines and the enterprise
Petroleos del Peru S.A.).
CO<2> emissions from fossil fuels were estimated to be 19,300 Gg.
However, if we consider the CO<2> generation by biomass consumption in
the residential and commercial sectors, the emissions will be increased
by 14,919 Gg. The contribution of other GHG's were moderate
(See Table 3-6).
Information in this sector was gathered from government
agencies such as the Ministry of Agriculture, Universities,
the Statistical National Institute (INEI), the Agrarian
Research Institute (INIAA), and others. Research articles,
theses, and the bibliography of special publications (FAO,
IVITA) were also reviewed. 98.1 percent of CO<2> emissions are
from activities associated with land-use change and forestry,
especially forest clearing. N<2>O is generated in minor amounts
(6.19 Gg). 51 percent of this comes from fertilizer use, the
burning of agricultural crop wastes, and savanna burning. The
other 49 percent is generated from the burning of cleared
NO emissions (121.53 Gg) result from activities associated
with agriculture, livestock, and land-use change. 41.2 percent of total
NO emissions come from the burning of agricultural crop waste and
savanna burning; the other 58.8 percent is generated from the burning of
cleared forests. The main source of CO emisssions is forest clearing
(59. percent), followed by the burning of agricultural wastes and
savannas (40.5 percent), then industrial processes, with 0.2 percent
of CO emissions resulting from lead manufacturing. Table 7 shows GHG
emissions for the nonenergy sector.
The main greenhouse gases from energy activities in the
country are CO<2> (19,300 Gg), followed by CO (622.712 Gg) and CH<4>
(82.96 Gg), with minor emissions of nitrogen oxides. The
transportation sector is the economic sector with the highest
contribution of CO<2> emissions from fossil fuel combustion, with
gasoline as the major source of CO<2>. Other important sectors are
residential, commercial, mining, metallurgy, fishing, public
services, agriculture, and livestock. Energy conversion
processes, particularly generating plants, also emit considerable
quantities of CO<2>. The industry sector has smaller emissions.
The main greenhouse gases from nonenergy activities in
the country are CO<2> (58,313.94 Gg), followed by CO (10,850.32
Gg), CH<4> (1,204.91 Gg), NO (121.53 Gg), and N<2>O (6.19 Gg). The
source that generates highest CO<2> emissions is land-use change
due to the burning of cleared forest and the conversion of
pastures to agriculture fields. On the other hand, the
abandonment of cultivated lands and managed forests reabsorb CO<2>
emissions and reduce the total CO<2> in the atmosphere.
Agriculture and livestock activities are the main sources
of methane emissions with 56.5 percent of the total emissions.
The main activities that contribute to high methane emissions
are breeding of animals, savanna burning, and rice cultivation.
National Council of Energy (CONERG), Ministry of Energy
and Mines, Lima 1990. Energy Balance 1990.
IPCC Draft Guidelines for National Greenhouse Gas
Inventories, December 1993. Greenhouse Gas Inventory Workbook,
Ministry of Transport, Communications, Housing and Construction,
Lima, December 1993. [The most important statistic
series of transport and communications 1985-1992]
Petroleos del Peru S.A., Public Relations Department,
Annual Memory 1990.
Petroleos del Peru, Estatistics of the Exploration/Production
National Enterprise of Electricity ELECTROPERU S.A.
Production and Energy Power Balance 1990.
Instituto Nacional de Estadistica e Informatica,
Anuario Estadistico 1990.
Ministerio de Agricultura. Boletin de la Produccion
Ministerio de Agricultura. Compendio Estadistico (1950-1991).
DANCE C.J. 1992. Potencial Forestal de la Amazona
Peruana: con Especial Referencia a la Selva Alta. UNALM.
FAO 1990. Forest Resources Assessment Tropical
Countries. Forestry paper #112, 86pp.
Rodriguez, L. 1986. La Agricultura Migratoria y Problemas de
la Conservacion, Politicas y Acciones 1986 a 1990 a cargo de
la direccion general de flora y fauna de las regiones agraria.
Malleux, J., 1975 Maapa Forestal del Peru. Memori Explicativa.
Lima-Peru. UNA. Departamento de Manejo Forestal.
Brown, S. and Lugo, E. 1984. Biomass of Tropical Forests:
A New Estimate Based on Forest Volumes.
Fearnside, P. 1987. Biomass of Brazil's Amazon forest.
An Improved Estimate for Assessing the Green House Impact
Instituto Nacional de Estadistica e Informatica (INEI),
Censos Nacionales 1993, IX de Poblacion, IV Vivienda,
Empresa de Servicios Municipales de Limpieza de Lima
(ESMLL). Boletin 1990.
Uruguay: Climate Change Vulnerability
and Adaptation Assessment Methods
for Coastal Resources and Agriculture
Annie Hareau, Raul Hofstadter, Cecilia Ramos-Mane,
and Andres A. Saizar
Uruguay Climate Change Country Study Team,
Comision Nacional sobre el Cambio Global, Montevideo, Uruguay
SUMMARY: This article describes the methods and expected results
of a research project for assessing Uruguay's vulnerability to
climate change and adaptation options regarding agriculture and
coastal resources. The study methodology has four basic steps: 1)
Data collection and compilation, 2) Development of climate change
scenarios, 3) Application of simulation model and other methods
to evaluate physical and socioeconomic impacts, 4) Evaluation of
adaptation options. The impact assessment for the agricultural
sector will address the main winter crops (wheat and barley) and
summer crops (maize and rice), and grasslands-livestock
production. Crop simulation models and soil nutrient dynamics
simulation models will be calibrated and validated. Models will
be run under a series of scenarios (baseline, GCMs, analogue and
incremental scenarios). Adaptive responses will be analyzed using
cost-benefit analysis techniques. Coastal resources analysis will
include initial application of a simple model using biophysical
and socioeconomic data under selected sea-level rise scenarios,
in order to identify and classify coastal units according to
sensitivity. More detailed models will be selected and validated
for studying the most sensitive areas. IPCC adaptation options
will be evaluated by conducting a cost-benefit analysis for each
coastal unit. Results will be made available as inputs for an
integrated coastal zone management plan. An education and
outreach strategy for the dissemination of relevant information
regarding both sectors to support policy and decisionmaking will
Scope of the Assessment
Previous studies at the international and regional level have
proved that natural and human-induced climate variations ranging
from short-term (i.e., seasonal to interannual variability due to
El Nino Southern Oscillation (ENSO)) to long-term changes (i.e.,
temperature shifts and sea-level rise associated with greenhouse
warming) may have a significant impact on water resources, on
grasslands and livestock, on agriculture and forests, on physical
aspects of the coastal zones, and even on human health. The
associated occurrence of extreme events like floods, droughts,
and severe weather conditions, as well as the steady change of
average climatic conditions and morphological variations of the
coastline are presently a matter of concern.
Climate change has been identified as one of the priority areas
for further research within the context of Uruguay's National
Research Program on Global Change (Comisi˘n Nacional Sobre el
Cambio Global, 1995). The present article describes the context
and methods for conducting a two-year sectoral vulnerability and
adaptation assessment within the framework of the Uruguay Climate
Change Country Study, initiated in late 1994 with support of the
U.S. Country Studies Program. This study is being carried out by
the Comision Nacional Sobre el Cambio Global (National Committee
for Global Change) of Uruguay with participation of the
University of the Republic, several Government agencies, and
nongovernmental institutions interested on the issue.
The impact assessment focuses on two sectors of particular
relevance to the Uruguayan economy: agriculture (including crops
as well as grasslands and livestock) and coastal resources. The
purpose of the study is to evaluate the impact of climate change
on natural systems and human activities in these sectors by
analyzing their sensitivity to selected climate change scenarios
and evaluating possible options for adapting to, and where
possible taking advantage of, new environmental conditions. The
results of this analysis will be used to promote public awareness
regarding climate change and to formulate national strategies.
Geographic and Socioeconomic Situation
Uruguay is located entirely within the temperate zone of southern
South America. Due to the country's small area (176.215 sq. km.)
and absence of high altitudes (maximum of 500 m), its climate is
almost homogeneous. It has been ranked as mesothermic subhumid
according to Koppen's classification (Koppen, 1931). Monthly
precipitation is uniformly distributed throughout the year, with
a slight increase in the fall. Its spatial distribution shows a
decreasing gradient in a NE-SW transect, with a maximum of total
annual values of 1,400 mm near the Brazilian border in the NE,
and a minimum of 900 mm in the southeastern part of the country
The country is located on the northern margin of the RĦo de la
Plata, one of the widest estuarine bodies in the world. It is one
of the five countries which make up the RĦo de la Plata Basin, a
vast region undergoing rapid urban and industrial development.
The Basin encloses an extensive hydrological network. Its regime
has been affected by dams for hydroelectric generation and
surface drainage of lowlands. Future modifications are foreseen
as a result of the development of a navigation waterway
(Hidrovia) connecting the northern countries of the Basin to the
Rio de la Plata.
Further, a large part of Uruguay's coastline lies on the
Southwestern Atlantic Ocean, next to the confluence of the Brazil
and Malvinas Currents. This complex system is known to
significantly affect regional atmospheric circulation patterns.
Uruguay's population amounts to little more than 3 million.
About 11 percent of the Gross Domestic Product (GDP) corresponds
to agricultural production, 25 percent to industries--which are
mostly devoted to processing of agriculture and livestock
products--and 64 percent to the commercial and services sectors
and others. Tourism, which mostly seeks Uruguayan coasts,
accounts for a significant portion of the latter.
Uruguay's agricultural sector is oriented to beef and wool
production on natural grasslands (85 percent of the country's
territory), dairy production, and crop production in an area of
about 4 percent of the country's territory. The climatic
conditions in the region allow for the production of subtropical
and temperate species, mainly wheat and barley as winter crops
and maize, rice, sorghum, and sunflower as summer crops.
Dominant soils in the country are Mollisols and Vertisols. They
are characterized by a high variability in their water-holding
capacity, their ability to supply nitrogen through mineralization
and their ease for tilling. Farm management practices in the
crop-growing area include rotating grain crops with pastures for
livestock raising. Commonly, a period of about two to three years
of crops is followed by four years of pastures (typically a mixture of
white and red clover, birdsfoot trefoil and tall fescue). As a result of
this system, soil conditions may vary depending on factors such as the
time since the pasture was plowed, the length of the pasture and
cropping stages, or the soil tillage practices.
Most of the beef and sheep products, as well as the barley and
rice grain, are exported. Beef, wool, hides, and cereals account
for about one-third of total exports.
Over the century, agricultural research has been devoted to
improving the production of dry matter of pastures during the
seasons of lower yields, i.e., in the winter due to low
temperatures, and in the summer due to the lack of soil water.
The introduction of species with high production potential and
nutritional value during these seasons has increased the forage
supply, especially in the dairy production area.
Crops have been improved through better management, including
planting dates, fertilization, and high-yield varieties adapted
to Uruguay's conditions. However, the heavy dependence of above
production on climate variability, particularly rainfall and
temperature, causes a high vulnerability of production systems to
potential climatic changes.
Little research has been conducted for assessing vulnerability
and adaptation options for the Uruguayan agricultural sector,
namely some studies on winter crops (Baethgen, 1994; Baethgen and
Magrin, 1995) which are serving as a background for this study.
Although Uruguay has long been known as an agricultural country,
its countryside is underpopulated while 70 percent of the total
population lives in cities along its 670 km of coastline on the
Rio de la Plata and the Atlantic Ocean. The Uruguayan coastline
is mostly characterized by the presence of long sandy beaches
bounded by rocky headlands. The coastline supports a tourist
industry which represents one of the main sources of income for
the country. The concentration of population in coastal cities,
as well as the development of summer resort areas, has generated
a significant investment in infrastructure of various types.
Investors from neighboring countries as well as from North
America and Europe have played an important role in the
development of the coastal area.
The potential long-term physical variations in the coastal
area, namely land loss and storm surge variations associated with
sea-level rise, and the consequent socioeconomic impacts have so
far been largely neglected in the implementation of development
plans, both by the public and private sectors. A first assessment
of the impacts of sea-level rise in Uruguay, which was conducted
by Volonte and Nicholls (1994), provides a useful basis for this
Vulnerability and Adaptation Analysis for the Agricultural Sector
Data Acquisition and Compilation
Information and data bases for the study are being made available
by various national institutions. Historical daily climate data
covering a period of about 40 years from several weather stations
throughout the country, as well as current climate data, will be
provided by the Direccion Nacional de MeteorologĦa (National
Meteorology Service). Additional climate information from selected
sites will be obtained from the Instituto Nacional de Investigacion
Agropecuaria (INIA) (National Agriculture Research Institute).
Data on temperature, precipitation, and solar radiation will
be compiled, digitized (when necessary), and verified. Soil maps
such as a 1:1,000,000 map for the entire country with profile
descriptions for dominant and associated soil groups, a 1:200,000
map of main crop-growing areas, and detailed maps with productivity
indices for all soil types in the country will be used. All maps will
be processed in a Geographical Information System (GIS) format.
Information on crops and pasture characteristics (e.g.,
phenology, quality, disease resistance, productivity), on
production systems (i.e., yields, fertility requirements, and
carryover effects), as well as on livestock production are
available from INIA and the School of Agronomy of the University
of the Republic. Additional current experimental information will
be obtained, as it becomes necessary, in coordination with such
institutions. Socioeconomic information will be obtained from
Government agencies, nongovernmental research organizations and
associations of farmers, as well as from published reports.
The study area is the entire territory of Uruguay. For the
purpose of this study, key geographical zones will be selected
combining information on climate, soils, topography, and
production systems. A GIS (ARC/INFO Software) will be used for
zoning purposes. Representative stations within each study unit
defined by means of the GIS will be selected for further
Development of Scenarios
Climate scenarios will be developed to estimate potential effects
of climate change on crops and grasslands-livestock production.
The following scenarios will be run:
-- Baseline scenario, using climatological data covering a
period of 30 years (1951-80)
-- Baseline scenario, with the direct effect of CO<2> on crops
and pasture production corresponding with an increase of the
atmospheric concentration of CO<2> to 440 ppm and 555 ppm
-- Climate change scenarios derived from General Circulation
Models (GCMs) under normal and doubled CO<2> concentration
conditions. The following GCMs will be used:
-- Goddard Institute of Space Sciences (GISS, Hansen et al.
1983; Hansen et al., 1989)
-- Geophysical Fluid Dynamics Laboratory (GFDL, Manabe and
-- United Kingdom Meteorological Office (UKMO, Wilson and
-- Other National Center for Atmospheric Research (NCAR) models
(Community Climate Model "CCM2")
Temperature changes for the first three GCMs listed (4.0-5.2oC)
are at or near the upper end of the range (1.5-4.5oC) projected
for doubled CO<2> warming by the Intergovernmental Panel on Climate
Change (IPCC, 1990a, 1992a). The GISS and GFDL scenarios are near
the mean temperature change (3.8oC) of recent doubled CO<2>
experiments documented for atmospheric GCMs with a seasonal cycle
and a mixed layer ocean (IPCC, 1992a).
-- Transient climate scenarios based on GCMs for the 2010s,
2030s, and 2050s.
-- Incremental scenarios, with a combination of changing temperatures
by 0, +2, +4oC, and changing precipitation by 0, +20 percent,
and -20 percent over the current values, each with and without
doubled CO<2> concentration.
Analogue scenarios, with special attention given to the
identification of weather anomalies from historical records and
extreme events (droughts and floods), such as those associated
with the occurrence of the different phases of ENSO, will be
The GCMs present many uncertainties regarding predictions, and
their ability to simulate current climate varies from region to region
(Rosenzweig et al., 1993). On the other hand, different GCMs predict
climate changes that are in some cases contradictory. For instance,
previous studies (Baethgen, 1994) of Uruguay show similar trends in the
average mean temperature for the GISS, GFDL and UKMO models, with an
increase in the monthly average of about 5oC. However, they show
contrasting trends in precipitation, since the GISS and UKMO models
predict a general increase in total precipitation, while the GFDL model
predicts a slight decrease. In spite of such uncertainties, GCMs are so
far the most advanced tools to predict potential future climatic
consequences of increasing radiatively active trace gases in the
atmosphere. The GCMs, combined with a local baseline scenario, and
incremental and analogue scenarios, are expected to provide an overview
of the potential future climatic conditions which could serve as a basis
for the impact assessment regarding Uruguayan resources.
Comprehensive economic development scenarios for the country are
not available so far. For the purpose of this study, general trends
based on historical socioeconomic data as well as estimated patterns of
development with regard to the agricultural sector will be considered
for the impact assessment.
Calibration and Validation of Models
The IBSNAT-ICASA (IBSNAT, 1989) crop models will be calibrated
with experimental data from trials carried out by INIA and the
School of Agronomy, and validated for the study area. Large
datasets are available in Uruguay to calibrate and validate
phenological and production genetic coefficients for simulation
models. A few experiments will be established to obtain other
required information. Background experience regarding validation
and regional adaptation of CERES models for winter crops will be
considered (Baethgen, 1994; Baethgen and Magrin, 1995)
A longtime step soil nutrient dynamics simulation model, namely
CENTURY (Parton et al., 1988), will be calibrated and validated
for assessing climate change impacts on grassland ecosystems,
while a short-time step model such as SPUR2 (Hanson et al., 1992)
will be used to assess impacts on grassland-livestock production.
Once the models are adequately validated, they will be used under
the different climate scenarios for estimating potential effects
of climate change on the:
-- Expected growth of the country's major agricultural crops
(wheat, barley, rice and maize) assessed through grain yield
components, total biomass, duration of growing period, grain
-- Expected pasture yields of the natural grasslands areas
-- Consequent effects on livestock production (dairy, beef, and wool)
Adaptive measures will be evaluated with the application of
simulation models to assess the options of reducing the impacts
of climate change or taking advantage of any positive new
conditions that may arise. Cost-benefit analysis of these
measures will also be conducted. The present study will attempt
to propose a comprehensive set of adaptive measures for crops and
grassland/livestock production under the different scenarios, on
the basis of their cost-benefit implications. These options will
be provided as tools for decisionmaking at the governmental,
farmer, and consumer levels.
A series of potential adaptive responses for the agricultural
sector based on international and local experience have been analyzed
a priori for the purpose of this study. Adaptive measures for crops
production could include genetic improvement and changes in management
practices and land use.
Regarding genetic improvement, for instance, it is estimated that
an increase in global temperature could negatively affect rice blooming,
and consequently yields. The development or selection of new varieties
of rice more resistant to high temperature at the blooming stage could
be attempted to reduce such impact. Selection of genotypes with lower
requirements of vernalization could be considered as an adaptation
measure to global warming in relation to wheat and barley.
Further, genetic improvement could account for the negative
effects on crops of an increase in climate variability, namely in
precipitation. For that purpose, cultivars with higher resistance
to environmental variations could be developed. The existence of
significant experience in agricultural research in Uruguay,
mainly at INIA and the School of Agronomy, would facilitate
future research aimed at the selection of crop varieties more
resistant to climate change or the testing of cultivars from
other regions for use under local conditions.
Regarding crop management practices, previous analysis carried
out for Uruguayan winter crops (Baethgen, 1994, Baethgen and
Magrin, 1995) have proposed the reduction of the impacts of
predicted unfavorable conditions by improving fertilization in
combination with modified planting dates. Further, the use of
soils with a better water balance--associated with appropriate
texture and depth--could account for deficiencies in soil water
content due to changes in precipitation patterns or higher
evapotranspiration. Thus, the area of Tacuarembo/Rivera located
at the northeast part of the country could be more suitable for
summer crops than the ones presently used in the western and
southern regions of the country, since their sandy soils present
higher water availability.
Irrigation of crops such as maize could account for lack of water
during droughts if an increase in the variability of precipitation
patterns occurs. Planting dates could also be changed according to new
climatic conditions, in order to allow for the development of new
cultivars. Further, fertilization could be improved in accordance with
the new adapted crops cycles, although this measure by itself might not
have a significant effect.
With relation to adaptation options for Uruguay, natural
grasslands, changes in grazing cycles, delayed grazing, or rotating
grazing could be considered. Seed sodding on natural pastures could
reduce negative climate change impacts on grasslands, thus representing
an appropriate method for mitigating the effects of the lack of water
and excessive temperature on pasture dry matter yields. The development
of combined pasture and forestry production systems could be better
adjusted to conditions of climatic variability, particularly in soils
which are sensitive to rainfall deficiencies.
Vulnerability and Adaptation Analysis of Coastal Resources
Data Acquisition and Compilation
There exists in Uruguay a considerable amount of information for
the analysis of the impact on coastal resources, either available
at national institutions or collected for specific studies, which
can be used for the present assessment. However, much of the data
need to be digitized and quality controlled.
Historical daily data on coastal water temperature, salinity, and
tides along the coasts of the Rio de la Plata and the Atlantic Ocean
are available from the Servicio de Oceanografia, Hidrografia y
Meteorologia de la Armada (SOHMA) (Navy's Oceanography, Hydrography
and Meteorology Service). Further data on physical and chemical water
conditions in the Rio de la Plata was collected during a pollution study
in the area (CARP-SOHMA-SIHN, 1989). Sediment distribution data for the
same area have been compiled in a Sediment Atlas (SOHMA, 1993). However,
oceanographic and sediment information for the oceanic area is more
sparse. Long-term historical climate data is available both from the
SOHMA and the National Meteorology Service.
General physical data, including coastal topography, bathymetry,
sediment types, and wave data, have been collected during a Government
study on beaches conservation (MTOP-PNUD-UNESCO, 1979). Additional wave
information will be generated through models due to the lack of
sufficient field data with the assistance of the Instituto de Mecanica
de los Fluidos e Ingenieria Ambiental (IMFIA) of the School of
Long-term tide gauge data collected at ports is available from
the National Hydrography Office.
A series of coastline maps as well as historical and current
aerial photographic records available at the Geographic Military
Service and the National Office of Environment, videotapes
obtained for previous studies (Volonte and Nicholls, 1994) as
well as satellite imagery will also be analyzed.
Besides the existing data, a one-year coastal monitoring program
will be set up to estimate the behavior of different stretches of
coastline when subject to storms. Data such as beach profiles,
observed wave heights, and sand grain size will be collected.
In addition to biophysical data, general qualitative and
quantitative information on economic activities and other social
and economic indices will be obtained from Government agencies,
published reports and articles, as well as from experts and local
Selection of Scenarios
Among the potential impacts of climate change in coastal areas, two
main aspects will be considered for the present study: an increase in
sea-level rise and a modification of wave characteristics.
Significant effort has been devoted at the international level to
develop sea-level rise scenarios. The most likely estimate of sea-level
rise by the year 2100 according to the IPCC will be tested. The sea-
level rise scenarios will include the current rate (0.2 m by 2100)
scenario (Douglas, 1991) and the accelerated rates (0.5 and 1.0 m)
scenarios (Wigley and Raper, 1992).
With regard to potential modification of wave characteristics, no
conclusive studies are so far available. Sensitivity analyses will be
performed in order to estimate potential changes associated with
increasing and decreasing storm energy and with shifts in direction of
deep water waves.
Climate change scenarios will be combined with socioeconomic
considerations to achieve a comprehensive assessment of potential
changes. Since economic development scenarios for the country are
not available, general trends based on historic socioeconomic
data, as well as estimated patterns of development for the
coastal area, will be considered for the impact assessment.
Preliminary Coastal Assessment and Zoning
The study area includes the entire Uruguayan coastal zone on the
RĦo de la Plata and the Atlantic Ocean. For the purpose of this
study, the term coastal zone refers to the area with mutual
influence of sea and land. Specific boundaries to such area will
be defined as appropriate during the study.
The first stage of the study will consist of a screening of the
entire coastal area to assess its overall vulnerability to
climate change and identify those zones potentially more
sensitive to sea-level rise. This preliminary assessment will be
based primarily on the analysis of available information and
The predicted physical conditions--namely modification of beach
profiles--under the selected scenarios will be determined. Erosion
assessment methods, such as Bruun's Rule (Bruun, 1962, 1983) will
be applied to the Uruguayan coast. Since inundation is not an
important process in the area, assessment of inundation impacts
will not be considered in this study. The selection and
validation for the area of other simple models to further assess
the effects of storms on the new equilibrium profiles will be
carried out. A general analysis will be further conducted for the
social and economic implications of the morphological changes,
namely cost of land loss, effects on coastal structures, and
effects on coastal activities.
Zoning will be carried out by means of a GIS with the results of
the preliminary screening. Homogeneous coastal units will be defined
and classified according to their sensitivity. Sensitivity indexes will
combine both physical and socioeconomic considerations. The most
sensitive coastal units will be selected for further analysis.
Biophysical Impact Analysis in Selected Coastal Units
A second stage of biophysical impact analysis in the selected
coastal units will be carried out under the sea-level rise
scenarios, in order to further assess potential morphological
changes in the area, namely land loss. General procedures for the
indepth analysis will be similar as for the preliminary
assessment. At this second stage, a more detailed model will be
selected and validated for the study area to estimate the effects
of sea level rise on the beach profile. For the purpose of this
analysis, the wave information will be transformed from deep
water to the near-shore zone more precisely--e.g. in the bottom
topography--for each coastal unit.
During the baseline impact analysis it will be assumed that no
adaptation policy is implemented. Therefore, it can be said that
the sheer effects of sea-level rise will be determined at this
stage. Once the effects on the beach profiles are determined, a
map of the predicted shoreline will be prepared. Geological
information will be overimposed to the erosion pattern to
validate the assumption about granular material erosion. An
additional study of the general effects of sea-level rise and the
consequent shift of the shore profile on the coastal biota will
be carried out. Special attention will be paid to benthic fauna
and to the typical flora adapted to the coastal environment.
A qualitative and quantitative assessment of the social and
economic consequences of potential changes in coastal
configuration under the climate change scenarios, namely the
values of present and future economic activities and resources
that might be lost, will be carried out. On each coastal unit
likely to be affected by sea-level rise, information on land
ownership (public or private) will be sought and value of land,
coastal infrastructure (e.g., ports, seawalls and breakwaters,
roads), beachfront houses, tourists resorts, buildings, and
commercial establishments will be estimated. Impacts of climate
change on the coastal activities (e.g., tourism) and associated
social indexes such as the level of employment will be further
assessed. On the basis of the biophysical and socioeconomic
information obtained, a preliminary assessment of the overall
vulnerability to climate change of the study zones will be sought
in order to analyze the response options that would be required
for each zone under the predicted scenarios.
The three basic adaptation options identified by the IPCC (IPCC,
1990b), namely retreat, accommodate, and protect, will be analyzed.
Each category will be developed to identify specific alternatives
for Uruguay. For each coastal unit the options will be compared by
estimating their costs and benefits. In the case of options requiring
maintenance, the annual cost will be calculated. A cost-benefit analysis
will be performed using the information of the investment costs and the
yearly maintenance costs.
For each coastal unit the possible adaptation options will be
ranked according to the results of the cost-benefit analysis, taking
into account social, economic, and environmental considerations. No
adaptation option will be selected, but advantages and disadvantages
will be pointed out in order to provide a tool for decisionmakers.
Further, the study will attempt to provide its results in such a fashion
that they could be easily incorporated into the process of the
formulation of an Integrated Coastal Zone Management (ICZM) Plan for
EDUCATION AND OUTREACH
The information produced or compiled during the study will serve
as a basis for the development of a national information system on
climate change, especially regarding vulnerability and adaptation.
The information will be made available to all potential users through
electronic media and reports.
The different target sectors that have been identified for the
preparation of an education and outreach plan are the political sector,
the Government, the business and industrial sectors, the educators, and
the general public. An overall survey of the degree of awareness and
knowledge of these sectors regarding climate change and its impacts, as
well as their interest in obtaining information on the subject and
applying it to decisionmaking processes, will be conducted at an early
stage of the education and outreach activities. Such a survey will be
performed by means of interviews and meetings.
Further, general dissemination of information is to be achieved
through workshops, seminars, and conferences; through deliverables
(publications, reports, brochures), and through the local press. The
basis for the formulation of a long-term education and outreach strategy
on climate change will be outlined jointly with Uruguayan institutions
with expertise in the educational and social communication fields.
Baethgen, W.E. 1994. Impact of climate change on barley in Uruguay:
Yield changes and analysis of Nitrogen management systems.
In Rosenzweig C. and A. Iglesias (eds.). Implications of climate
change for international agriculture: Crop modeling study.
EPA 230-B-94-003. U.S. Environmental Protection Agency.
Baethgen, W.E. and G.O. Magrin. 1995. Assessing the impacts of
climate change on winter crop production in Uruguay and Argentina
using crop simulation models. In press.
Bruun, P. 1962. Sea-level rise as a cause of shore erosion.
American Society Civil Engineers Proceedings. Journal of
Waterways & Harbors Division, 88:117-130
Bruun, P. 1983. Review of conditions for uses of the Bruun Rule
of erosion. Coastal Engineering, 7:77-89.
CARP-SOHMA-SIHN. 1989. Comision Administradora del Rio de la Plata--
Servicio de Oceanografia, Hidrografia y MeteorologĦa de la Armada,
Uruguay--Servicio de HidrografĦa Naval, Argentina. Estudio para la
evaluacion de la contaminacion en el RĦo de la Plata. Informe de avance.
Comision Nacional sobre el Cambio Global. 1995. Programa Nacional
de Investigacion en Cambio Global. Montevideo, Uruguay. (Unpublished)
Corsi, W.C. 1978. Clima. In Avances en Pasturas IV. Miscelanea
18: 255-256. Centro de Investigaciones Agricolas Roberto Berger.
La Estanzuela. Uruguay
Douglas,B.C. 1991. Global sea-level rise. Journal of Geophysical
Hansen, J., I. Fung, A. Lacis, D. Rind, S. Lebedeff, R. Ruedy and
G. Russell. 1989. Global climate changes as forecasted by the
Goddard Institute for Space Studies three-dimensional model.
Journal of Geophysical Research, 93:9341-9364.
Hansen, J., G. Russell, D. Rind, P. Stone, A. Lacis, S. Lebedeff,
R. Ruedy and L. Travis. 1983. Efficient three-dimensional global
models for climate studies: Models I and II, Monthly Weather Review,
Hanson, J.D., et al. 1992. SPUR2 Documentation and users guide.
U.S. Department of Agriculture. Great Plain Research Technical Report 1.
IBSNAT. 1989 International Benchmark Sites Network for Agrotechnology
Transfer Project. Decision Support System for Agrotechnology Transfer
Version 2.1. (DSSAT V2.1.). Department of Agronomy and Soil Science,
College of Tropical Agriculture and Human Resources, University of
IPCC. 1990a. Houghton, J.T., G.J. Jenkins and J.J. Ephraums (eds.).
Climate Change: The IPCC Scientific Assessment. Intergovernmental Panel
on Climate Change. Cambridge University Press.
IPCC. 1990b. Strategies for adaptation to Sea Level Rise. Report
of the Coastal Zone Management Subgroup, Intergovernmental Panel
on Climate Change. Rijwaterstaat, The Netherlands.
IPCC. 1992. Houghton, J.T., B.A. Callander and S.K. Varney, (eds.).
Climate Change 1992. The supplementary report of the IPCC scientific
assessment. Intergovernmental Panel on Climate Change. Cambridge
Koppen, W. 1931. Grundriss der Klimakunde. De Gruiter, Berlin.Manabe,
S. and R.T. Wetherald. 1987. Large-scale changes in soil wetness induced
by an increase in carbon dioxide. Journal of Atmospheric Science.
MTOP-PNUD-UNESCO. 1980. Ministerio de Transporte y Obras
Publicas--Programa de las Naciones Unidas para el Desarrollo--UNESCO.
Conservacion y Mejora de Playas. UNDP/URU/73/007.
Informe Tecnico. Uruguay
Parton, W.J., J.W.B. Stewart and C.V. Cole. 1988. Dynamics of
C,N,P, and S in grassland soils: A model. Biochemistry, 5:109-131.
Rosenzweig, C., M.L. Parry, G. Fischer and K. Frohberg. 1993.
Climate change and food supply. Research Report 3. Environmental
Change Unit. University of Oxford
SOHMA. 1993. Atlas Sedimentologico del RĦo de la Plata. J. Lopez
Volonte C.R. and R.J. Nicholls. 1994. The impacts of sea-level
rise on the coastline of Uruguay. Proceedings of the International
Workshop: Global Climate Change and the rising challenge of the sea.
Margarita Island, Venezuela, March 1992.
Wigley, T.M.L. and S.C.B. Raper. 1992. Implications for climate
and sea level of revised IPCC emissions scenarios. Nature, 357:293-324.
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sensitivity experiment with a global model including a simple
ocean. Journal of Geophysical Research, 92:13315-13343.
Venezuela: Preliminary National
Greenhouse Gas Inventory
Martha Perdomo, Nora Pereira, Yamil Bonduki,
Ministry of Environment and Renewable Natural Resources,
Ministry of Energy and Mines
SUMMARY: This paper presents a summary of the "Preliminary Inventory
on Sources and Sinks of Greenhouse Gases in Venezuela," whose final
version will be submitted to the United Nations Framework Convention
on Climate Change (UNFCCC), as an official document of the
Venezuelan Government. This inventory is one of the components of
the National Study to Address Climate Change. The gases included in
this inventory are carbon dioxide, methane, nitrous oxide, carbon
monoxide, and nonmethane volatile organic compounds.
Chlorofluorocarbons are excluded as they are controlled by the
Montreal Protocol. Table 1 provides a summary of greenhouse gas
emissions by source category. The energy sector is the most
important anthropogenic source in the country. Emissions mainly come
from the use of energy as fuel, land-use change, and from fugitive
emissions generated by oil and gas production. Carbon dioxide is the
most important gas, its emissions originate primarily from fuel
combustion and forest clearing. Methane has also an important
contribution to national emissions of greenhouse gases, and it
originates primarily from oil and gas production and agricultural
activities. This national inventory represents a valuable tool to
redict future greenhouse gas emissions under various economic
development scenarios and to identify the best mitigation strategies
that the country could implement to reduce its emission levels.
Atmospheric concentrations of greenhouse gases have been
increasing as a result of a wide range of human activities and
have become particularly noticeable after the 1950s. This
increase is believed to alter the redistribution of energy in the
atmosphere and, consequently, affect climate by altering some
related natural phenomenon, such as the mean global temperature,
and changes in frequency and distribution of precipitation,
circulation and weather patterns, and hydrological cycle, among
The possibility of a global climate change, as a result of
anthropogenic emissions of greenhouse gases, has become a major
concern within the international scientific community in the last
few years. Such concern was the basis for the creation of the
Intergovernmental Panel on Climate Change (IPCC) and for the
process of international negotiations that led to the approval of
the United Framework Convention on Climate Change (UNFCCC). The
Government of Venezuela also signed the Convention which was
ratified by the National Congress on December 1994.
As the Convention requires all parties to develop and publish
national inventories of anthropogenic greenhouse gas emissions as
well as national plans to reduce or control emissions, the Ministry of
Environment and Renewable Natural Resources and the Ministry of Energy
and Mines developed the Country Study to Address Climate Change. The
study was initiated in October 1993, with the financial and technical
assistance of the Government of the United States, through the U.S.
Country Study Program (USCSP), and the Global Environmental Facility
(GEF), through the United Nations Environmental Programme (UNEP).
A team of experts from several Venezuelan ministries and
institutions are in charge of conducting this study, with the
-- Develop a national inventory of anthropogenic emissions by
sources and removals by sinks of all greenhouse gases in
accordance with IPCC guidelines.
-- Predict future greenhouse gas emissions under various
economic development scenarios.
-- Identify, analyze, and rank abatement strategies through the
formulation of a national plan to mitigate greenhouse gas
emissions in the country and enhance reservoirs and sinks.
-- Assess the potential impacts generated by sea level rise on
Margarita Island and Venezuelan coastal zones and outline the
possible adaptation responses.
-- Assess the potential impacts and adaptation strategies on
Venezuelan forests due to climate change.
A study of this kind is very important for a developing country
like Venezuela, whose current national plans include programs of
industrial development, increased public services, and expansion
of petroleum industry activities. All of these national development
programs will likely increase greenhouse gas emissions, unless programs
of conservation, efficient use of energy, and methane gas control are
implemented simultaneously. These development plans have also affected
forest areas extensively as the establishment of a wide range of
economic activities have been traditionally linked to land clearing.
The final project reports are intended to be released as official
documents of the Government of Venezuela as a first step to implementing
the guidelines set forth in the United Nations Framework Convention on
The estimation of emissions from all sources was based on the
methodology provided by the IPCC Draft Guidelines for National
Greenhouse Gas Inventories (IPCC/OECD, 1994). Some default values
provided by the methodology for specific variables and emission factors
were used in the inventory as local data were not always available.
In many cases, the required data were specifically generated for the
inventory through literature search, site visits, or interviews with
experts. In a few cases, specific studies were performed in order to
produce or validate some of the data.
The results of this inventory are also presented in accordance
with the IPCC guidelines, following the reporting instruction tables.
Besides the analysis and estimates of 1990 greenhouse gas emissions and
sinks, the document to be submitted to UNFCCC provides a global picture
of the main anthropogenic activities responsible for these emissions in
the country and a description of particular situations that could
introduce additional elements in the inventory process. It also provides
specific discussions on methodologies, data used, and information
sources for each category.
The international standards set for the inventory process, based
on a common methodology, seek to ensure that all mechanisms and
approaches adopted by the countries to evaluate their greenhouse gas
emissions are consistent and transparent and that their results can be
compared on a systematic manner.
RESULTS AND DISCUSSION
The following section summarizes the emission estimates and presents
a brief discussion on the relative importance of each source category
within the national inventory of greenhouse gas emissions.
Carbon dioxide contributes to nearly one third of the natural
greenhouse effect. A continuous increase of its concentration in the
atmosphere, produced by anthropogenic activities, has been observed from
the beginning of the industrial period. At a global level, since then,
the concentration of carbon dioxide has increased by more than
25 percent, mainly due to the use of fossil fuel. Venezuela generated
190,813 Gg of carbon dioxide in 1990. The main sources are energy
combustion and land-use change (Figure 1).
The use of fossil fuels constitutes the main anthropogenic source
of greenhouse gases. Within this, carbon dioxide is the most important
contributor; emissions of this gas occur during the combustion process,
when the carbon contained in the fuel is combined with oxygen. The
quantity of carbon in fossil fuels varies significantly by fuel type.
Coal contains the greatest amount of carbon per unit of energy, while
crude oil and natural gas contain 25 percent and 50 percent less than
In Venezuela, the energy sector emitted 107,334 Gg of carbon
dioxide in 1990, which represented 56 percent of national emissions of
this gas. Energy combustion generated 105,976 Gg (98.7 percent of the
energy sector), while gas flaring in the oil and gas systems produced
the remainder 1,358 Gg (1.3 percent of the sector).
Carbon dioxide emissions from combustion are mainly caused by the
use of oil and natural gas. The former generated 53,313 Gg, while
emissions from natural gas were estimated to be 50,742 Gg, which
represented 50 percent and 48 percent of these emissions, respectively.
Coal represented only 2 percent of these emissions since coal
consumption in the country is very low. Regarding emission estimates of
carbon dioxide by sectors, as shown in Figure 2, the emissions come
mainly from the transportation sector (36 percent) and the operations of
the energy industry (38 percent).
Stationary Sources: In 1990, stationary sources emitted 51,560 Gg
of carbon dioxide, mainly from the use of oil (31 percent) and natural
gas (67 percent). The greatest amount of emissions within the stationary
sources corresponds to the energy industry, which generated 30,516 Gg.
The sources of emissions in this industry are related primarily to
electricity generation (19,519 Gg) and oil and gas production
The second largest source is the manufacturing industry, which
generated 16,775 Gg of CO<2>. Most of these emissions come from energy
used for steam generation (41 percent) and direct heat (44 percent).
The industrial categories that produce the greatest quantities of
emissions are: basic metallic; food, beverages and tobacco; chemicals
and nonmetallic mineral industries, which all together generated
86 percent of the emissions from the manufacture sector.
The residential sector generated 3,678 Gg of CO<2> while the
commercial and service sectors emitted 572 Gg. Regarding the fuel
types used in this sectors, petroleum is the main emitter, followed
by natural gas.
Mobile Sources: The 1990 emissions of carbon dioxide from mobile
sources were estimated to be 29,205 Gg; 88 percent corresponds to
national transportation and the remainder to different types of
international transport. Gasoline vehicles are the most important
emitter, with 21,760 Gg.
Emissions from national transportation are basically generated by
road transportation (93 percent). The emissions released from private
vehicles are the most important within this sector, with 10,593 Gg of
carbon dioxide in 1990, which represented 39 percent, followed by the
emissions from heavy duty trucks, with 27 percent. Emissions from
public transportation are the least significant, as they only
contributed with 14.4 percent.
Land-Use Change and Forest Management
Human activities that alter the biosphere for food, fuel, and fiber
production have been increasingly contributing to the concentration of
greenhouse gases in the atmosphere. Carbon dioxide is considered to be
the most important gas associated with land-use changes. Three
categories are considered in the national inventory: forest clearing,
forest management, and conversion of grasslands to cultivated lands.
Land-use change is largely responsible for greenhouse gas emissions in
Venezuela. The forest conversion process that the country has witnessed
during the last decades has increased significantly as land pressure to
establish different economic activities has determined the fate of large
forest areas. Furthermore, land clearing for agricultural use is the
most important activity leading the process of land-use change.
Forest Clearing: The forest area of the country is roughly 58
million hectares, which represents more than 60 percent of the
national territory. About 70 percent of the forest land is found
in the south of the country, where the Venezuelan Amazonian Basin
The annual rate of forest clearing in Venezuela has not been
consistently documented. The country was divided into three main
geographical regions, according to specific sources of information
on forest-clearing rates: Northwest, northeast, and south, in order
to derive an average deforestation rate. The analysis estimated an
average cleared area of approximately 517.000 hectares per year
(excluding the southern region), which represents a deforestation rate
of less than 1 percent per year. This value was used to provide an
approximation of greenhouse emissions in the country due to forest
clearing until a more detailed study on deforestation rates at a
national level is performed. An initiative is already being coordinated
to achieve this goal in the near future.
The amount of carbon dioxide emitted by forest clearing has been
estimated to be 84,792 Gg in 1990, which represents about 44 percent of
national CO<2> emissions. Being one of the most important sources of
carbon dioxide and other gases as well as one of the most complex areas,
a number of issues will still need to be refined in order to improve the
estimates and update the inventory.
Managed Forests: Carbon dioxide uptake from managed forests has
been estimated to be 5,380 Gg in 1990, which represents an offset of
about 6 percent and 3 percent of CO<2> emissions from forest clearing
and all sources, respectively. Although its importance as a carbon
dioxide sink may not seem relevant within the national greenhouse gas
emission context, the potential contribution of forest management to
offsetting CO<2> emissions is quite large. The total forest area managed
by commercial forest product industries during the 1970-90 period has
reached 215,000 hectares. On the other hand, forest plantations have
reached, for the same period, about 430.000 hectares. More than 90
percent of the area corresponds to commercial plantations while the rest
has been established for protection purposes.
Conversion of Grasslands to Agricultural Lands.
Conversion of grasslands to cultivated lands is not a significant
source of carbon dioxide in the country, as agricultural activities
have been rather marginal within the national economic development
context. Most of the agricultural activities in these areas are
related to extensive cattle raising, which does not involve land
tilling. However, some important crops have been established on open
savannas, especially during the 1984-89 period, when government
subsidies resulted in a substantial increase of agricultural production.
Based on local data for soil carbon content, the estimated net converted
area, and a rate of soil loss carbon of 2 percent per year, emissions
were calculated to be 1,200 Gg of carbon dioxide. As the data used are
not very reliable, the result obtained is highly uncertain and should be
viewed as a general approximation of the magnitude of emissions
from this source.
Methane is the second most important gas responsible for global warming,
accounting for about 15 percent of the "radiative forcing" added to the
atmosphere in the 1980s, at a global level. Methane levels are
increasing substantially, as its concentration have more than doubled in
the past 300 years and continue to increase by about 1 percent per year.
Although global methane emissions are much smaller than global carbon
dioxide emissions, its overall contribution to global warming is large
since it is 22 times more effective at trapping heat in the atmosphere
over 100-year time horizon when direct and indirect effects are
Methane emissions in Venezuela were estimated to be 3,168 Gg for
1990. The major anthropogenic sources are: fugitive emissions
from production and processing of oil and natural gas and
emissions from agricultural activities (Figure 3).
The energy sector emitted 1,838 Gg of methane in 1990, which
represented 58 percent of national methane emissions. Fugitive
emissions are the most important source of this gas with 99.3
percent while fuel combustion only generated 0.7 percent.
Oil and gas systems are the main methane emitters, especially
during production activities, which generated around 83 percent
of the total fugitive emissions. Emissions corresponding to processing,
transportation, and distribution of natural gas represented 17 percent.
The contribution of coal mining is very small, due to the low level of
production of this fuel in the country.
The use of fossil fuel in transportation is the most important
source of emissions of the non-CO<2> originated by combustion,
mainly those generated by incomplete combustion, such as methane.
The mobile sector is the second largest emitter of methane with
9.8 Gg, representing 81 percent of combustion emissions; gasoline
vehicles produced the biggest amounts, especially private
vehicles, which generated 4.9 Gg.
Methane is the most important greenhouse gas produced by the
agricultural sector and is responsible for the emission of 951 Gg,
which represents 30 percent on the national methane emissions.
Management of domestic livestock and animal manure contributes 90
percent of the methane emissions from agricultural activities. Rice
cultivation and savanna burning are a less important source of methane,
releasing 7 percent and 3 percent of the emissions from agricultural
activities, respectively. Field burning of agricultural residues
are a negligible source of methane and other greenhouse gases as
this practice is not common in the country.
Enteric Fermentation: Emissions from enteric fermentation in
domestic animals are estimated to be 826 Gg of methane, which
represents about 26 percent of national methane emissions and 87
percent of methane emissions from agricultural activities. The more
detailed approach of the IPCC methodology, referred to as Tier 2, was
applied in order to derive methane emissions from cattle. Dairy and
beef cattle are the major contributors, accounting for 97 percent of
total emissions from enteric fermentation. Methane emissions from other
domestic animals include buffalo, sheep, horses, swine, goats, mules,
and asses. The approach used to calculate the emissions from these
noncattle sources was based on the Tier 1 method, and consequently a
less detailed analysis was performed. Methane emissions from these
animals have been calculated to be 23.2 Gg, about 3 percent of methane
emissions from enteric fermentation in all domestic animals.
Manure Management: Methane emissions from animal manure are
estimated to be 26.7 Gg, which represents only 3 percent of the total
amount generated by domestic livestock and less than 1 percent of
national methane emissions. Manure in the country is usually not treated
or stored in anaerobic environments. Thus, almost all livestock manure
is managed as solid on pastures and ranges. Of the different animal
categories included in this estimate, cattle and swine manure are the
most significant emitters, accounting for approximately 55 percent and
34 percent of total methane emissions from animal manure, respectively.
Rice Production: Rice fields generate about 67 Gg of methane per
year and represent 2 percent of national methane emissions. Rice is one
of the country's major crops and most of its production is concentrated
in two regions with similar climate patterns and cultivation practice
Rice fields are commonly irrigated or rainfed with a depth of less than
one meter of floodwater, which is a basic condition to generate methane
through the anaerobic decomposition of organic matter in the fields.
Although some variations were found in the number of days flooded per
year, this period has an average of nearly 90 days, corresponding to a
continuously flooded regime. Rice is not cultivated under intermittently
flooded or dry regimes in the country.
Savanna Burning: More than one-fourth of the country (approximately
22 million hectares) is covered by savannas, found in most geographical
regions, but mainly in the Llanos of the central part of the country.
Extensive cattle raising has been traditionally established on savanna
areas, which involves burning during the dry season, as a common
agricultural practice to eliminate weeds and pests and encourage growth
of new grass. This periodical burning of a great portion of savanna
areas releases important non-CO<2> trace gases. Carbon dioxide, which is
also emitted in large quantities, is not taken into account in the
greenhouse gas inventory for this sector because it is reabsorbed by the
vegetation regrowth between the burning cycles. Methane emissions from
this source were estimated to be 31 Gg, which represents only 1 percent
of methane national emissions.
The proportion of the savanna areas burned in Venezuela is highly
uncertain as there are not reliable national statistics that compile, on
a regular basis, the frequency and extent of savanna burning.
Consequently, a satellite imagery study (Landsat TM, 1:250.000 scale)
was performed on about half of the savanna area of the country in order
to determine this figure. An extrapolation of the study's results
indicates that approximately 3.1 million hectares of savanna are
annually burned, which represents only 13 percent of the country's
savanna area. These results are very controversial as the proportion of
savanna burned appears to be very low, especially when compared to the
regional data provided by the IPCC methodology. From this source,
savannas are burned worldwide every 1 to 4 years on average
Burning of Agricultural Residues in the Fields: The contribution
of this source to greenhouse gas emissions in the country is rather
negligible as only 0.2 Gg of methane were generated by agricultural
waste burning. Most of the agricultural residues are not burned since
they are commonly used to feed cattle and other animals or plowed back
into the field during land tilling. The only two crops whose residues
are indeed burned for different reasons are sugar cane and cotton. Sugar
cane fields are traditionally burned before the harvest for both
practical and safety reasons. Cotton residues are also burned but mainly
for sanitary reasons in order to eliminate any possible pest or weed
that may affect the health and yield of the following crop.
Landfills do not constitute a significant source of methane in the
country since a great fraction of solid wastes is still disposed of in
open dumping. Sanitary landfilling generates 221 Gg of methane, which
represents about 7 percent of national emissions. Twenty landfills were
identified, with a wide size range. The smallest of these receives an
average of less than 3,000 Ton of solid wastes per year while more than
1 million Ton per year are placed in the biggest landfill. The latter
alone, which serves the capital's metropolitan area, accounts for more
than 40 percent of the total landfilled waste in the country.
Other activities that generate methane in the country are related
to land-use change and wastewater management. Biomass burning that
occurs in conjunction with forest clearing has been included in the
national inventory. Emissions from this practice were estimated to be
158 Gg, which represents nearly 5 percent of national methane emissions.
This estimate will be updated once the deforestation rate data are
validated. Wastewater treatment is a negligible emitter of greenhouse
gases as only 0.2 Gg of methane were generated by this source.
Nitrous oxide is another important infrared absorbing trace gas
that contributes to the greenhouse effect. According to the World
Meteorological Organization (WMO) its current atmospheric
concentration is about 8 percent greater than during the
preindustrial era. Nitrous oxide is approximately 270 times more
powerful than CO<2> at trapping heat in the atmosphere over a
100-year time horizon. The current rate of accumulation of N<2>O in
the atmosphere is about 0.2 percent to 0.3 percent per year.
Although the estimates are relatively uncertain, nitrous oxide
emissions in Venezuela were calculated to be 4.54 Gg for 1990.
The most important contributor is the agricultural sector, especially
the use of fertilizer (agricultural soil management). Nitrous oxide is
also produced directly from biomass burning in the nonenergy sector and
combustion of fossil fuels (Figure 4). Nevertheless, the mechanisms that
cause its formation from these sources are not well understood. N<2>O
production is highly temperature-dependent.
The Venezuelan energy sector is the least important contributor to
nitrous oxide emissions with 0.64 Gg, representing 14 percent of the
national emissions in 1990. Within this sector, 66 percent comes from
mobile sources, especially road vehicles (93 percent); the highest
proportion corresponds to heavy-duty trucks. Contrary to the
industrialized countries estimates, where fuel consumption, mainly from
aged 3-way catalytic converters, is an important emitter, in Venezuela
this source is the least relevant since the vehicle fleet has not yet
incorporated catalytic converter control.
Stationary sources emitted 0.22 Gg of nitrous oxides (34 percent
of the combustion emissions) where 46 percent comes from energy
and transformation industries, 38 percent from manufacture
industry, and 18 percent from residential and commercial sectors.
Agricultural Soil Management
In 1990, nitrous oxide emission from the use of chemical fertilizers
were estimated to be 2.3 Gg. This is the main source of nitrous oxide
in Venezuela, and represents 50 percent of total N<2>O emissions in the
country and approximately 85 percent of the agricultural sector's
emissions. Organic fertilizers are not included in this estimate due
to the lack of the required data. Although some crop residues and animal
manure are used in certain agricultural fields, this type of fertilizer
does not usually enter the commercial market, and consequently, no
reliable source of information is available to estimate the total amount
of organic fertilizer and the equivalent nitrogen content.
Other sources of nitrous oxides in the country are related to biomass
burning as a result of land use change and agricultural practices. Both
forest burning that occurs in conjunction with land clearing and savanna
burning account for 1.2 Gg of nitrous oxide, which represents about
27 percent of this gas national emissions. Agricultural waste burning is
a negligible source of nitrous oxide.
Carbon Monoxide and Nonmethane Volatile Organic Compounds
Carbon monoxide and nonmethane volatile organic compounds (NMVOCs)
are unburned gaseous fuels that are emitted in small quantities due
to incomplete combustion. They contribute to the formation of urban
smog and hence they have been the target of emission control policies
in some ccountries. The impact of thes gases on global climate is
indirect. The most important of these effects is their role as
precursors of tropospheric ozone. In this role, they contribute to
ozone formation and alter the atmospheric lifetimes of other greenhouse
gases. However, many uncertainties are associated with quantifying the
Carbon monoxide emissions in Venezuela were estimated to be
4,101 Gg for 1990, where agriculture acclivities and land use change
contributed with 55 percent while energy combustion represented
45 percent of national emissions (Figure 5). All nonmethane volatile
organic compounds are emitted by the transport sector, which generated
250 Gg in 1990.
In energy combustion, emissions of these gases are directly influenced
by usage patterns, technology type and size, vintage, maintenance and
operation of the technology, and usage patterns. Emissions can vary by
several orders of magnitude for facilities that are improperly
maintained and poorly operated such as the case of many older units.
Carbon monoxide emissions from the Venezuelan energy sector were
basically generated by the transport sector, which produced 98 percent;
the remainder 2 percent corresponded to stationary sources, especially
from the manufacture industry. It is important to mention that almost
all emissions of carbon monoxide (98 percent) and NMVOCs (96 percent)
are generated by gasoline vehicles.
The need to manage a wide range of variables and the numerous
conditions that could affect the yield of each mobile sources category,
especially those related to road transport, make very difficult any
attempt to generalize the emission characteristics in this area. A
similar situation is observed for stationary sources since the emission
factors provided by the IPCC methodology are not sufficiently
disaggregated. Some adjustments were made in order to perform the
Savanna burning represents an important source of carbon monoxide in
the country. This agricultural practice generates 820 Gg or 20 percent
of national carbon monoxide emissions. However, since the proportion
of savanna burned calculated for the country is believed to be
underestimated, the emissions from this source could increase
significantly once more reliable data is incorporated in the national
inventory. If the default value of 50 percent burned on average per year
is used to perform the estimate, as provided by the IPCC methodology for
the Latin American region, carbon monoxide emissions from this source
would be four times higher than the result obtained in this preliminary
inventory. This issue will need further discussions in order to provide
a more reliable estimate of greenhouse gases from savanna burning.
Forest burning that occurs in conjunction with land clearing is
responsible for more than a third of the national carbon monoxide
emissions, as 1,380 Gg of the gas were emitted from this source
in 1990. Contrary to savanna burning, emissions from this source may
be overestimated as a result of the rather high value obtained for
deforestation rate in the country. Although the average cleared
area used for the inventory still does not cover the entire country,
discussions with several experts have pointed out the fact that some
methodological limitation of the deforestation rate study may be
responsible for inconsistencies in the results. An initiative is
already underway to clarify this issue in the near future.
Nitrogen oxides have been the target of environmental policies for
their role in forming ozone, as well as for their direct acidification
effects. NO are also produced by incomplete combustion. In Venezuela,
NO emissions in 1990 were estimated to be 360 Gg, generated mainly by
combustion of fossil fuels, with 90 percent of national emissions of
this gas. The remainder 8 percent corresponded to biomass burning in the
nonenergy sector (Figure 6).
Similarly to carbon monoxide and NMVOCs, nitrogen oxides are a
technology-dependent gas. Their emissions depend in part on the
nitrogen contained in the fuel. Electricity generation and
industrial fuel combustion activities also provide combustion
conditions conducive to NO formation. Excess air and high
temperatures contributes to high NO emissions. They are also
produced from incomplete combustion.
As mentioned above, the most important NO source is the
combustion of fossil fuels, with 126 Gg from stationary sources
and 199 Gg from mobiles. Electricity generation contributed with
55 percent of the emissions from the stationaries. In mobile sources,
98 percent was produced by road transportation where the principal
source is gasoline heavy-duty vehicles.
As in the case of nitrous oxide, biomass burning associated to
land-use change and agricultural practices constitutes another
source of nitrogen oxides emissions. Forest burning that occurs
in conjunction with land clearing, savanna burning, and
agricultural waste burning account for 25 Gg of nitrogen oxides,
which represents about 8 percent of this gas national emissions.
This preliminary national inventory provides a comprehensive picture
of Venezuelan greenhouse gas emissions and constitutes a powerful tool
to evaluate and plan the best mitigation strategies that the country
could develop to reduce and control its emission levels. Nevertheless,
some weaknesses and limitations still represent an important problem to
be addressed in order to improve the reliability of the information used
as well as the methodologies applied in some cases.
Most source categories are likely to present qualitative and
quantitative limitations reflected in the calculation of greenhouse gas
emissions. However, the uncertainties associated with the emission
estimates were not quantified due to the limited available information
and the difficulty of identifying the level of reliability for most of
the data used in the inventory. Besides limitations associated with the
methodology, the poor quality of some of the data is probably highly
responsible for the uncertainties of the results. Special efforts should
be made in the near future to solve this crucial issue and produce more
accurate national estimates.
In the case of the energy sector, indepth studies have already
been initiated for the main carbon dioxide emission sources, with the
objective of validating the data and generating more appropriate
emission factors. Similarly, as land-use change represents a significant
source of carbon dioxide, an effort to determine more reliable data on
deforestation rates is being coordinated by the Ministry of Environment
and Renewable Natural Resources. Methane emission estimates could also
be improved through the implementation of specific projects to generate
additional and more reliable data for the oil and gas industry--the main
source of methane. A project will be formulated shortly to address this
issue in conjunction with the Venezuelan Oil Industry.
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Zimbabwe: Climate Change Impacts on Maize
Production and Adaptive Measures
for the Agricultural Sector
C. H. Matarira,/1/ J. M. Makadho,/2/ F. C. Mwamuka/3/
/1/Scientific and Industrial Research and Development Centre (SIRDC)
SUMMARY: This paper reports the results of the crop vulnerability
and adaptation element of Zimbabwe's country study. Global Climate
Models (GCMs) and dynamic crop growth models were used to assess the
potential effects of climate change on agriculture in Zimbabwe.
These effects were estimated for maize, since maize is the most
widely grown crop in Zimbabwe. Its growth increasingly coming under
stress due to high temperature and low rainfall conditions.
Projected climate change causes simulated maize yields to decrease
dramatically under dryland conditions in some regions (in some cases
up to 30 percent), even under full irrigation conditions. The
reduction in modeled maize yields are primarily attributed to
temperature increases that shorten the crop growth period,
particularly the grain-filling period. Broadly speaking, the
duration of crop growth becomes shorter, thereby causing dramatic
negative effects on yields. The simulated yield decreases in some
regions are partially offset by the effect of increased CO<2> on
plant physiology. There are several potential adaptation strategies
that may be used to offset the negative impacts of climate change on
maize yields. These include switching to drought-tolerant small
grains and maize varieties, and appropriate management practices.
Some farmers might suffer because of relatively severe local
climatic changes, while farmers in other areas might benefit through
improved yields and/or higher prices as a result of favorable
local climatic conditions. Rapid geographical shifts in the
agricultural land base could disrupt rural communities and their
associated infrastructure. More research is called for to
generate technologies that equip farmers to adapt to the effects
of climate change.
Despite the uncertainties of potential climate change, a scientific
consensus is emerging that increasing concentrations of atmospheric
CO<2> could alter global temperatures and precipitation patterns. Most
agricultural impacts studies (Rosenzweig et al., 1993; Muchena, 1991;
Magadza, 1992) are based on the results of Global Circulation Models
(GCMs). These climate models indicate that levels of greenhouse gases
are likely, among other things, to increase global average surface
temperatures by 1.5 to 4.5oC over the next 100 years. Downing (1992)
used a simple index of the atmospheric water balance to assess how
agricultural land use may be affected due to changes in water resources.
He found out the following:
-- With temperature increase of 2oC the wet zones of Zimbabwe
(with a water surplus) decrease by a third from 9 percent to
about 2.5 percent.
-- The drier zones will double in area.
-- A further increase in temperature to +4oC reduces the summer
water-surplus zones to less than 2 percent of Zimbabwe,
approximately corresponding to the 1991-92 drought.
-- In addition to a shrinkage of the agricultural area, crop
yields in marginal zones would become more variable.
Simulations done by Muchena (1991) indicate that with +2oC of warming,
yields currently expected 70 percent of the time would be exceeded only
in 40 percent of the years. Such studies indicate that smallholder
farmers in the marginal semiarid regions of Zimbabwe are the most
vulnerable to climate change.
Objectives of the Study
The major objective of the study is to assess, using crop simulation
models, the effect of climate change on agriculture and adaptation
strategies with special reference to maize production in Zimbabwe.
The following specific objectives have been derived:
-- To provide results of crop simulation models using observed
baseline data, climate change scenarios with or without simulations
of direct effects of CO<2> on crop growth, irrigated production,
and adaptation responses, such as planting dates and appropriate
-- To show the effects of climate change by quantifying crop yield,
season length, growing season precipitation, and evapotranspiration.
-- To identify and evaluate possible measures in agricultural practices
that would lessen any adverse effects of climate change.
-- To project the economic consequences and implications of
Selection of Study Areas
Four stations, each representing a natural region, were chosen. These
were Karoi, Gweru, Masvingo, and Beitbridge, representing Natural
Regions II, III, IV, and V respectively.
Baseline Climate data
Daily observed climate data (precipitation, solar radiation, maximum
and minimum air temperature) on each of the stations were collated by
the Department of Meteorology for the period 1951 to 1991. The data were
manipulated accordingly and formatted for entry into the crop simulation
Climate Change Scenarios
Using the GCMs, the observed climate data were modified to create
climate change scenarios for each site. The GCMs used were developed
by the Geophysical Fluid Dynamics Laboratory (GFDL) and the Canadian
Climate Centre Model (CCCM). The GCMs compute climate variables for
different longitude and latitude gridboxes and according to the
literature reviewed by the authors, they do not seem to give a
comprehensive account for the variations within the gridbox. Daily
changes in climate variables from doubled CO<2> simulations of the two
GCMs were applied to the observed daily climate records to create
climate change scenarios for each site. Climate change scenarios
were created from GCMs because they produce climate variables that
are internally consistent and because they allow for comparisons
between or among regions. Because the water supply in Zimbabwe depends
entirely upon climate conditions, any decrease in precipitation could
be most significant for the irrigation water available to the crops.
Considering the large temperature increases anticipated due to climate
change and their potential effect on evapotranspiration, the GCM
scenarios would imply water shortages, particularly in the sites that
are currently in low rainfall areas.
Crop Model Inputs and Simulations
The maize simulation model used was the CERES-Maize model. The model
simulates crop responses to changes in climate, management variables,
soils, and different levels of CO<2> in the atmosphere. The software
used to run the programs was developed by the Decision Support System
for Agro-technology Transfer (DSSAT) and includes database management,
crop models, and application programs (Tsuji et al. 1990). Potential
changes in maize physiological responses (yields, season length,
evapotranspiration, irrigation demand in a daily time step) were
estimated using the CERES-Maize model under different climate scenarios.
The model simulates physiological crop responses (water balance,
phenology, and growth throughout the season) on a daily basis to the
major factors of climate (daily solar radiation, maximum and minimum
temperature, and precipitation), soils and management (cultivar,
planting date, plant population, row spacing, and sowing depth).
Some assumptions were made in applying the crop model and they
tended to overestimate the simulated yields. These are as follows:
-- Nutrients are nonlimiting
-- Pests are controlled
-- There are no problematic soil conditions
-- There are no catastrophic weather events
-- Technology and the climate tolerance of cultivars do not
change under conditions of climate change
Cultivar and Management Variables
A short season maize variety, R201, commonly grown under dryland
conditions, was selected for the study in the four sites. R201 is
a variety that would perform in both high and low rainfall areas.
The "genetic coefficients" of R201 were obtained from the
Agricultural Research Trust in Harare.
Maize in Zimbabwe is grown under supplementary irrigation,
particularly in large-scale commercial areas. This management activity
cannot be simulated with the CERES-Maize model. Maize in this study was
simulated under dryland and irrigated conditions to provide a range of
possible scenarios and analyze the production changes. Since it is not
possible to determine the amounts of irrigation water for each region,
irrigation was simulated under the automatic option in order to provide
the crop with a hypothetical nonlimiting situation. The amount of
irrigation water used is obviously overestimated and consequently,
so will be the yields obtained. Nevertheless, this approach allows
comparison between relative changes in each site. If arbitrary
irrigation amounts were applied, the uncertainty of the results would
be larger and there would be inherent errors when comparing results from
For the irrigation simulation, the water demand was calculated
assuming the following:
-- 100 percent efficiency of the automatic irrigation system
-- 30cm irrigation management depth
-- Automatic irrigation when the available soil moisture is
50 percent or less of capacity
-- Soil moisture for each layer is reinitialized to 100 percent
capacity at the start of each growing season
-- The plant population was kept the same in both dryland and
irrigated conditions at 4.4 plants m to the (-2) power
Soils in Zimbabwe are predominantly derived from granite and are
often sandy and light-textured, with low agricultural potential
due to low nutrient content, particularly nitrogen and phosphorus.
Nevertheless, there is a significant portion of soils in all regions
with a heavier clay content that is more suitable for crop growth.
The representative soils are medium sandy loams in Karoi and Gweru,
and sandy clay loams in Masvingo and Beitbridge (as described in
Effects of CO<2> on Plant Physiology
The climate change scenarios have higher levels of CO<2> than the
current climate. The CERES-Maize model includes an option to simulate
the physiological effects of CO<2> on photosynthesis and water-use
efficiency that gives higher crop yields (Acock and Allen 1985). For all
climate scenarios included in this study, maize was simulated under the
normal climate conditions and then under conditions of climate change.
These simulations also included the simulated physiological effects of
CO<2> on crop growth and yield.
Validation of the Crop Model
The CERES-Maize model was validated using local experimental crop data.
The experimental data included aspects like cultivar, planting date,
growth analysis, fertilizer application, harvesting date, and final
yield components. Experimental crop data and climate were used for the
1988-89 season at Harare Research Station, and for the 1986-87 season at
Gweru. At Harare Research Station, the observed yield was 9.5 percent
lower than the simulated yield, and the observed season length was 2.3
percent shorter than the simulated season length. In Gweru, the mean
observed yield was 3 percent lower than the simulated yield and the
observed season length was 1.6 percent longer than the simulated season
length. These results do indicate that CERES-Maize model is an adequate
tool to simulate maize growth, particularly to evaluate relative changes
in crop yield in relation to planting date.
Under the GFDL Model the effect of climate change gives an average
increase of 8 percent in precipitation at Beitbridge for all planting
dates. There is reduction by 10 percent, 11 percent and 17 percent in
available precipitation at Masvingo, Gweru and Karoi respectively.
It should be further noted that at all sites, the reduction in
precipitation is highest for maize planted early (15 November) and
gets progressively lower towards late planting date (15 December).
This implies that early planted maize may not get adequate precipitation
under climate change conditions.
The simulation results are presented in Tables 1 and 2 and reveal
a number of insights as follows:
-- Maize production at all stations is more consistent under
normal climate than under climate change conditions. Climate
change introduces greater variability in maize yields, thus
making maize production a more risky agricultural activity.
-- At Masvingo, which represents Natural Region IV, there is a
strong likelihood that climate change will make the Region a
nonmaize-producing area. If this becomes real, the whole of
Natural Region IV, which represents 42 percent of communal
areas, will not adequately supply its population with the staple
-- Late planted maize at all sites will not give yields that make maize
production a viable activity under climate change conditions.
-- Climate change will give rise to significant yield increases
in Natural Regions II and III, but this will depend on proper
timing of planting dates to get the maximum benefit.
-- Even though irrigation will boost maize production in all areas,
the yields are lower under climate change conditions than under
-- The length of the crop growing season will be shortened under
climate change conditions. This will limit maize production
to short-season varieties.
-- Precipitation available per growing season will be reduced
by more than 20 percent due to climate change at all sites. The
greatest reduction in available precipitation is encountered when
maize is planted early rather than late.
-- The reduction in mean seasonal precipitation under climate
change conditions implies that the water available for irrigation
purposes would also be affected accordingly. This will reduce the
effectiveness of irrigation as a strategy to combat the effects
of climate change.
-- The semiextensive farming zone (Natural Region IV) is the
most sensitive and most severely affected by climate change.
This has been revealed in the simulated maize yields obtained under
climate change scenarios. The farmers in this zone constitute the
majority of farmers in communal areas and they will be further
marginalized due to climate change.
-- Increased variations in rainfall, temperature, season length
and yield would alter the mix of appropriate response strategies.
Even Natural Regions II and III, which do not seem to be severely
affected by climate change, have to take advantage of the good
seasons by making full use of weather information and adopting
appropriate management practices.
-- More importantly, broad-scale shifts in agricultural capability
due to climate change would affect rural livelihood and the national
economy. This implies that all vulnerable groups are threatened by
climate change through the ripple effects that diminish the resource
base and increase the possibility of resource conflicts and tensions
between the agricultural and industrial sectors.
On the whole, the simulated changes in crop yields are driven by two
factors, i.e., changes in climate and CO<2> enrichment. The interactions
of these factors on the baseline crop growth are often complex. However,
yield decreases are caused primarily by the increase in temperature,
which shortens the duration of the crop growth stages particularly the
grain fill period. The season length is greatly reduced under these
The simulated evapotranspiration decreases in most areas despite
the large increases in temperature and potential evaporation. This is
due to the shorter growing season, which reduces the total amount of
evapotranspiration, and the decreased demand of moisture by the crop,
since it is not growing at capacity. The amount of irrigation water used
will generally decrease for the same reasons. Another problem is that
the initial soil water conditions are reset each year to "full," which
is not always very realistic.
Zimbabwe's agricultural sector currently represents the largest
force driving the country's economy. Agricultural production
processes, particularly plant growth, are dependent on climatic
conditions. This makes agricultural activities extremely
vulnerable to climatic changes. Thus, it is essential to study
the potential effects of climate change on the agricultural
sector and to examine ways in which the sector can adapt in order
to minimize the negative socioeconomic impacts of these changes.
There is still considerable uncertainty in our understanding of
climate change and its effects (Smit 1993). At finer spatial scales,
such as at the state/national level, uncertainty about climate change
increases (Smith and Mueller-Vollmer 1993). Given such uncertainties,
it would seem sensible to take a reactive approach to adaptation, that
is, the adaptive measures are taken after or as a response to climate.
The reactive approach may not, however, produce satisfactory results
and may prove to be too costly. Thus, there is a need to examine
anticipatory approaches to adaptation. The goal of anticipatory measures
is to minimize the impact of climate change by reducing vulnerability
(e.g., sensitivity) to its effects or by enabling reactive adaptation to
happen more efficiently, that is, faster and at lower cost (Smith and
For the agricultural sector, adaptations to climate change can
occur at two levels:
1. The farm level
2. The national level as reflected in government policy
Although agriculture is very sensitive to climate, it may be among the
most flexible of the societal systems sensitive to climate change. As a
unit exposed to impact, agriculture is thus a moving target, continually
adjusting itself both to perceived climatic and nonclimatic conditions
(Parry and Duinker 1990). This paper, thus, looks at the measures that
may be undertaken both at the farm and national levels in order to adapt
the Zimbabwean agricultural sector to climate change.
Farm Level Adaptations
At the farm level, the potential for agricultural adaptation is very
high. Farm level adaptations arise from the farmers' perception of
changed or changing conditions. Already the farmers are operating in
an environment where climatic conditions vary from place to place and
from season to season. In the past fifteen years Zimbabwe has
experienced three droughts (1982-83, 1987-88, and 1991-92 seasons) of
varying severity. This has alerted the farmers to the need to reexamine
land use and management practices and farm infrastructure.
Changes in Land Use
Parry and Duinker (1990) have identified the Southern African
region as one of the regions that appear most vulnerable to
climate change. In Zimbabwe, climate change is therefore likely
to increase the climatic constraints on agricultural production.
Marginally productive areas are likely to be lost to non-agricultural
use, thus reducing the area under agricultural production. For areas
where croppingg becomes nonviable, livestoc and dairy production can
take over as the major agricultural activity. Farmers may also switch
to different crop types or change to more drought-and disease-tolerant
crops. Farmers may introduce irrigation systems in areas where high
temperatures and rates of evapotranspiration lead to reduced levels of
available moisture. Switching from monocultures to more diversified
agricultural production systems will help farmers to cope with changing
climatic conditions. Monocultures are more vulnerable to climate change,
pests, and diseases. The use of livestock breeds adaptable to drought
and the use of supplementary feeds (including tree crop fodder) will
give farmers greater flexibility in adapting to climate change.
Changes in Management and Infrastructure
Changes in management practices can offset many of the potentially
negative impacts of climate change (Smith and Mueller-Vollmer 1993).
The timing of various farming operations (e.g., planting dates,
application of fertilizers, pesticides, and weedicides) will become
more critical if farmers are to reduce their vulnerability to the
impacts of climate change. Besides the timing of the various operations,
planting densities and application rates of agro-chemicals and
fertilizers will also be of major importance. The use of conservation
tillage, intercropping and crop rotation practices will enhance the
long-term sustainability of soils and improve the resilience of crops
to changes due to climate change (EPA 1992). Farmers may also consider
the use of greenhouses for the production of some of their products.
There will be an increasing need to use irrigation in areas where
there are increases in evapotranspiration. Because of the need for
tighter water management practices in order to counter increased demand,
the use of more efficient irrigation systems can be expected. For
orchards and vines, drip-irrigation systems can be used to conserve
water. Water losses through seepage and evaporation in canal- and flood-
irrigation systems can be minimized by lining the canals with cement or
switching to pipe-irrigation systems. The significantly higher costs of
production related to irrigation systems will most likely result in
shifts to less water-demanding uses in areas where there are higher
rates of moisture loss. Livestock and dairy farmers can make use of
supplementary feeds and fodder trees as low-cost grazing systems become
less sustainable in areas that become marginal. Farmers can also explore
the use of improved pastures using municipal waste water.
Changes in the types of agricultural production and irrigation
systems will require significant changes in farm layout and the types of
capital equipment employed. In areas where there is a need to use
irrigation systems, there may be need for additional water reservoirs or
boreholes. Parry and Duinker (1990) have noted that because of the large
costs involved in infrastructural changes, only small incremental
adjustments may occur without changes in government policy.
National Level Adaptations
Agriculture is affected in many ways by a wide range of government
policies that influence input costs, product pricing and marketing
arrangements. Parry and Duinker (1990) have noted that relatively minor
alterations to these policies can have a marked and quite rapid effect
on agriculture. Thus, changes in government policy as a result of
climate change or anticipated change would have a very significant
influence on how agriculture ultimately responds. Government policies
pertaining to land and water resources, which represent the basic
foundation for agricultural production, should be more explicit in
having the implementing agencies give due consideration to the possible
impacts of climate change. Given the uncertainties about the magnitude
and rate of change (especially at finer scales), the prospects of
government acting directly to promote adaptation to anticipated change
are rather limited. It is, thus, imperative that any anticipatory
measures considered allow the greatest flexibility in order to allow
these measures to be revised as new information about the magnitude and
direction of climate change becomes available. Through its policies on
infrastructural developments, research and development, education and
water resources management, and product pricing, government can put both
reactive and anticipatory adaptive measures into place. Ideally, a
policy-relevant research program could help identify appropriate actions
as the current state of knowledge evolves (OTA 1993).
The government is currently constructing a number of medium- to large
sized dams throughout the country. Even though this may be a reaction to
droughts of the recent past, this can still be considered to be
anticipatory. Increasing the capacity and number of such dams at this
stage would be less costly than at a later stage. With the construction
of these dams, irrigation schemes can also be established. Some
irrigation schemes are already operational in some areas. Rukuni (1993),
cited in Rukuni (1994), notes that there is growing evidence of high
rates of return to investments in smallholder irrigation schemes, and
that large areas of shallow ground water could be put to intensive
cultivation if research focused on some aspects of environmental
protection as well as on developing low volume water pumps. There is
a need for government to undertake a major review of land-use
planning with due consideration given to an integrated resources
management approach. Thus, the current exercise to assess Land
Tenure Systems suitable for Zimbabwe should seriously consider
the conferring of ownership to land owners together with the
formal obligations on the part of the owner to use the land in a
sustainable and productive way. Government agencies in charge of
executing the resettlement program can also take into consideration
the anticipated impacts of climate change. Though the resettlement
programs have been primarily targeted at relieving population pressure
from the communal areas, it is important to note that most of these
areas are marginal and will become more vulnerable with climate change.
Thus, if the resettlement programs are executed with due regard to
climate change, they can be made more efficient and enhance the
sustainability of agricultural production in these marginal areas. As
more areas become marginal, there will be a shift to more intensive
agricultural production in the more favorable areas. Hence, if such
areas can be identified, supporting infrastructure (e.g., transportation
and communication networks, and markets) can be improved in these areas.
The setup of such infrastructure may not be critical at this stage;
however, it can still be fully utilized and significantly improve
agricultural production efficiency in these areas. Its most critical
significance, however, will become more apparent as adaptive measures
become more efficiently implemented and the impacts of climate change
Research and Development
Government support for research and development can have significant
impacts on the agricultural sector. Its policy and support for research
and development in the private sector will also be of major
significance. The availability of facilities, level of funding and
outlook on private sector initiative will greatly influence the rate
at which crop varieties, livestock breeds, agricultural technologies,
and management systems adaptable to climate change can be implemented.
There is a need for research on crops and livestock that are more
tolerant to disease and drought conditions. Research on short-season
high-yielding crop varieties and livestock breeds will be of paramount
importance to adaptation. Government expectations to increase wheat
production from 300,000 tons in 1990 to about 487,000 tons in 1995, and
to a level of national self-sufficiency thereafter (GOZ 1991) are very
noble. These expectations should, however, be considered in the context
of future climate changes. Thus, in order to realize and sustain these
expectations in an environment of changed climate, the government needs
to commit itself to supporting an intensified program of research into
higher-yielding, drought-hardy, and disease- and pest-tolerant wheat
Government's aim of promoting increased goat production in
Natural Regions III, IV and V (GOZ 1991) should seriously take into
consideration the marginality of these regions. Goats, by nature, are
very destructive to the environment if not managed properly. With
climate change, the vulnerability of these marginal regions will be
increased. Thus, government should support research efforts aimed at
ascertaining how to effectively increase and sustain goat production in
these regions without detrimental effects on the environment.
Other research areas requiring increased government support
are agro-chemicals and fertilizer development, improved pastures and
tree fodder crops, irrigation systems, low-input agriculture, and
agroforestry systems. The government will also need to support research
on diseases and pests, both those currently afflicting the agricultural
sector and those that may come about due to climate change.
There will also be need for research in effective storage systems
for agricultural products. The government recognizes the utility of
improvements to storage, processing, and preservation techniques in
overcoming production shortages (GOZ 1991). It, however, has not made a
firm commitment to undertaking such improvements. The government has
made a commitment for 500,000 to 600,000 tons of grain to be kept by the
GMB as a strategic reserve for use by the urban population and in times
of drought or similar disasters (GOZ 1991). From events of the recent
past, however, it has been evident that the rural majority are hardest
hit in the event of a drought. Thus, the government should seriously
consider supporting research in a more decentralized manner and
maintaining these strategic reserves with increased local participation.
An enabling environment and government support would encourage the
private sector to invest more resources into these areas of research.
Private sector participation will most certainly result in more rapid
application of research output within the agricultural sector. The
government should also establish seed banks for crop varieties adaptable
to different climatic conditions.
There is a need to bridge the institutional separation of
research and extension services, as this has tended to minimize
the responsibility for developing technology that is farmer-based
and problem-oriented. It is also important that government fully
utilize information from research and development bodies in its
formulation and/or reformulation of policies impacting on the
agricultural sector. The government should carefully examine the
inadvertent damage to the capacities of research and development
institutions as a result of budgetary and staff cuts under the
Economic and Structural Adjustment Programme. There is also a
need for improved incentives to attract and retain outstanding
scientists in these research and development institutions.
Education and Water Resources Management
In Zimbabwe, a fairly significant amount of agricultural produce
comes from the small scale and subsistence farmers. The greatest
challenge to government lies in the sensitization of subsistence
farmers to the impacts of climate change. These farmers already
operate in the most marginal areas and are certainly the most
vulnerable group. There is need for a more intensified approach
to making these farmers conscientious with regard to the need for
crop diversification, crop switching, conservation tillage, and
water conservation. In most areas, livestock owned by subsistence
farmers already far exceeds the carrying capacities of the marginal
land they occupy. This is another area that will require a more
intensive government awareness program. Government can also actively
encourage crop switching and diversification, and the use of appropriate
fertilizers whenever they assist small-scale and subsistence farmers
through the drought recovery program. Government should also consider
the possibility of setting up a high-level interagency task force to
develop a coherent national drought policy. Such a task force would
examine the viability of establishing a national drought insurance
scheme and would spearhead an awareness campaign on matters related to
drought and other impacts of climate change.
Eicher (1993) singles out political leadership as one of the
most underrated ingredients of agricultural development (cited in
Rukuni 1994). There is, thus, a need to empower adequately the small
scale and subsistence farmers so that they have their own political
voice and clout. This would enable them to organize themselves into
unions, commodity groups, and cooperatives in order for government to
get a balanced view of the rural majority. Hence, with an enhanced
awareness of their rights and an enabling environment, consistent with
human rights and democratic governance, it would be legally and
institutionally easier for the farmers to form such groupings. Such
groupings would enhance the flow of information to the farmers, thereby
making it easier to communicate research results with respect to
adaptations to climate change.
There will be a need for government to review current policy
on water rights. The new policy should reflect the need to conserve
and utilize water resources more efficiently. It should reflect the
increasing need to share equitably a diminishing resource. The
government can support and offer incentives to farmers undertaking
infrastructural developments that will lead to the conservation or
increased availability of water resources. There will also be a need
for government to explore the possibilities of interbasin water
transfers in order to enhance the sustainability of areas that become
intensively used for agricultural production or become marginal as a
result of climate change.
Input Costs and Product Pricing
The implementation of the Economic Structural Adjustment Programme
has resulted in major reform and commercialization, particularly with
respect to market and trade liberalization. Market liberalization,
however, should not result in the marginalization of the small-scale
and subsistence farmers. There is, therefore, a need for government to
establish and strengthen existing institutions that are geared toward
extending credit to small-scale and subsistence farmers, and facilitate
cost-effective marketing of their produce. There are many cases of
successful national public agricultural research stories that show that
smallholder farmers can seize market opportunities in a favorable
macroeconomic environment (Rukuni 1994). However, input costs and
product pricing can function as incentives or disincentives in
determining which agricultural products to produce. Thus, pricing policy
can be used to steer the agricultural sector in a direction more
adaptable to climate change. Through pricing policy, government can
actively influence crop switching, water conservation measures, and a
host of other management activities, making the agricultural sector
adaptable to climate change.
The estimated effects of climate change as evidenced in the
simulated maize yields is indicative of the potential problems
ahead of us. New and fluctuating weather patterns could have
severe negative impacts on economic activities, particularly in
the natural resources sector. Zimbabwe, which is highly dependent
on the agricultural production sector, could see a rapid deterioration
in the livelihood of her citizens as a result of climate change.
Without the appropriate policies or adaptive strategies in place,
the smallholder farmers will find it extremely difficult to operate
sustainable agricultural production systems in an environment with
changed climatic conditions. The potential solutions to agricultural
sector problems resulting from climate change will require increased
financial resources, a greater commitment to research efforts to
develop and acquire new technologies, and the development and
application of fairly high managerial skills.
If Zimbabwe is to remain the breadbasket of the SADC Region
and meet the growing demands for food locally and regionally, the
sustainable growth of the agricultural production sector should
be given the highest priority in all national development programs.
Climate change compounds the need to increase the efforts to improve
the knowledge and skills of farmers, remove constraints to farmer
adaptability and innovation, and expand the options available to
farmers. An expansion of the diversity of crops and farm technologies
available will improve the chances of adapting successfully to a future
in which existing farming systems are threatened by climate change.
Thus, anticipatory measures will enhance the adaptability of farmers by
speeding up the rate at which farming systems can be adapted to climate
change, and will significantly lower the potentially high costs
associated with adjustment.
Constraints to adjusting to climate change are numerous. The
considerable uncertainties about the magnitude and extent of the
impacts of climate change make it relatively difficult to come up
with appropriate responses (policy formulation and strategy
development). Because of these uncertainties, any anticipatory
measures undertaken should be of maximum flexibility in order for
them to be beneficial to the agricultural sector even without
climate change, and they should allow for readjustment as more
knowledge about climate change is gained. The decline in the
provision of resources to support agricultural research and
extension is also another problem. More research and extension
programs will enhance our capacities to adapt to climate change.
Climate change is slowly taking place. This change will result
in impacts whose direction, magnitude, timing, and path are neither
fully understood nor accurately predictable. There is, thus, a need
for sustained scientific research to enable the prediction of the
impacts of climate change with more confidence, especially at the
regional and national levels. Hence, we can begin to develop and
implement the most appropriate resource management strategies and
technologies to combat the impacts of climate change on the agricultural
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[END OF SECTION 4]
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