Zimbabwe: Climate Change Impacts on Maize Production and Adaptive Measures for the Agricultural Sector

C. H. Matarira

Scientific and Industrial Research and Development Centre

J. M. Makadho

Agritex

F. C. Mwamuka

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 is 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 CO₂ 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.

INTRODUCTION

Despite the uncertainties of potential climate change, a scientific consensus is emerging that increasing concentrations of atmospheric CO₂ 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 4.5°C 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 2°C 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 +4°C 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 +2°C 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.

To provide results of crop simulation models using observed baseline data, climate change scenarios with or without simulations of direct effects of CO₂ on crop growth, irrigated production, and adaptation responses, such as planting dates and appropriate maize varieties.
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 climate change.

METHODOLOGY

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 model.

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 CO₂ 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 CO₂ 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
here 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 different sites.

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^-2

Soils
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 Nyamapfene 1991).

Effects of CO₂ on Plant Physiology
The climate change scenarios have higher levels of CO₂ than the current climate. The CERES-Maize model includes an option to simulate the physiological effects of CO₂ 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 CO₂ 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.

RESULTS

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 food crop.
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 normal climate.
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 CO₂ 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 scenarios.

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.

Results shown in tables {1 , 2} reveal some significant variations in maize yields and length of growing season at different sites due to Climate change.

ADAPTATION

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 easures 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 Mueller-Vollmer 1993).

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 cropping becomes nonviable, livestock 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.

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).

Infrastructural Developments

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 are minimized.

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 varieties.

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.

CONCLUSIONS

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 sector.

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INTERIM REPORT ON CLIMATE CHANGE COUNTRY STUDIES
March 1995

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