The Agricultural Implications of Global Climate Change


The following material is a proposal for scientific research into the agricultural implications of global climate change (in particular global warming). Using previously compiled data from a host of various sources, we will examine some of the predicted changes in agricultural systems, those peoples most likely to be affected by change, and some of the proposed means of adapting to/alleviating negative consequences of change.



Our primary focus concerns the agricultural implications of global climate change as it affects regional systems. Our proposal concludes with recommendations for the future of agriculture based on the evident disparity between MDCs and LDCs as far as climate change vulnerabilities and response capabilities.


The last few decades of scientific research and inquiry have revealed an increase in global temperatures and a shift in global precipitation patterns. Studies indicate a rise in temperature in the range of .5-.7 degrees C in the last one hundred years. Though the definitive causal factor (or factors) is heatedly debated within scientific and political circles, much evidence of the phenomenon of climatic change is virtually uncontestable.">Click here for a Quicktime movie of temperature changes starting in the early twentieth century and finishing at the close of the twenty-first century.


A more complex debate surrounds the various implications of climate change for our planet's natural and human systems. The early Malthusian-esque forecasts of impending doom have been abandoned for a more rational approach to examining specific regional affects and experimenting with potential adaptations.
Due to the fact that climate change will affect both natural and human systems, it is important to study the effects of change at the point where these two systems intimately meet: agriculture.

We intend to explore three primary questions in the course of our research. 1.) What major changes will most drastically effect the current agricultural system? 2.) Who will be affected by negative changes in the agricultural system? 3.) What measures, if any, can be applied to adapt and/or alleviate the negative consequences of agricultural change?


Planning a golf outing or a picnic in 100 years from now? Take today's temperature(Oxford, Ohio) and add this:



1.  Major Climatic Changes directly affecting agriculture:


    a. Rising sea level decreases coastal land.  This is problematic because the majority of the world's

        population resides on our near the coast. Furthermore, the majority of the world's population is

        located in LDCs in increasingly greater proportions as total world population grows.

    b. Shifting rainfall patterns will change the growing locations of various crops. Some regions

        will be better suited for agriculture, while others will experience decreased yields.

    c. Shifting temperature ranges will affect changes in the lengths of growing seasons.  Farmers

        will need to adjust planting and harvesting dates.


2. Reactions in MDCs versus LDCs


    a. LDCs will become increasingly dependent on MDCs.

            1.  food aid

            2.  pesticides, herbicides, fertilizers

            3.  agricultural technologies, ie genetic engineering


    b. MDCs will suffer a disproportionate amount of the net negative affects on agricultural and human systems.

            1.  economic wherewithal

            2.  agricultural policies


3. Adaptations


    a.  Research into the global causes and regional affects of climate change.

    b.  International and domestic policy changes to protect small farmers' interests on the global

         market and the food security of the people of LDCs.

    c.  Initiative to build sustainable infrastructure in LDCs, and international commitment to assist

        LDCs in sustainable development (which includes refraining from practices or actions which

        compromise the long-term interests of developing nations' environments and citizens).">Click here for a short movie on the changes that the landscape in England will undergo as a result of global warming.  According to the narrator, if warming continues at the same rate we are experiencing now, England will one day become a prime location for vineyards!!!!




It is our intention to examine the key issues surrounding the human agriculture system. Of the 80,000 potentially edible plants on the Earth, humans rely on only 30 species of plants for 95% of our nutrition. A mere 8 crops supply 75% of our diet. (Biosphere 2000) Agricultural production per capita has seen an average increase of 2.25 % in the last fifty years. This increase in productivity is largely a result of the implementation of agricultural technologies heralded by the "green revolution." It is also based on the fact that, during this period, net agricultural productivity grew faster than population. Since 1990, though, per capita food production in developing countries has consistently declined. Also, virtually one half of the world's food production occurs in countries with agricultural growth rates of less than 2.25%.  (Boonekamp 2000) The U.S. Census Bureau has projected that the global population will reach 9.35 billion by the year 2050.

    In addition, this increase will occur primarily in developing nations whose populations are also expected to realize higher life expectancies over the same time period. (Foster and Leathers 1999) In light of these and other startling projections and within the context of global climate change, some scientists, for the first time in history, have begun to discuss the potential for absolute global food shortage.

The advent of global warming will have major affects on future agricultural productivity. As production increases to accommodate a growing population, so do emissions of the greenhouse gases carbon dioxide, methane, and nitrous oxide, further exacerbating warming. Global warming will manifest itself in numerous ways and probably have a more dramatic affect on regional rather than global crop yields. Rising temperatures and changing rainfall patterns will affect the kinds of crops that can grow in a particular place. Some areas, such as coastal regions, will no longer be suited for agriculture due to salt-water intrusion into freshwater aquifers (preventing irrigation) or flooding of prime agricultural land. However, other regions may experience a growth in productivity due to global warming; such regions may see a longer growing season, and rising levels of carbon dioxide tend to increase the efficiency of photosynthesis, thus accelerating plant growth. Wheat, rice and soybeans are especially responsive to higher levels of CO2, characterized by C3 pathways in the course of photosynthesis.

While C3 plants will show increased productivity in correlation with initial increases in CO2 , over time, productivity will level off even as CO2 continues to increase.


 Higher average temperatures are also correlated with higher incidences of insect reproduction and disease. (Johnson 1991) These changes may result in an increased use of pesticide and herbicide use, which has serious implications for the health of natural systems, including humans of course.  Higher global temperatures could also result in a dramatic loss of biodiversity, due to pole-ward and altitudinal shifts in species' ranges.

This diagram illustrates some of the effects global warming will have on agriculture.

There is much evidence to suggest that global warming would not adversely affect agricultural productivity in the United States; our country has the financial resources to invest in research programs and technologies that could help its producers adapt to changes. Genetic engineering, for example, could be used to develop crops that would flourish in any climate. Even poorer farmers could adjust planting dates, crop varieties, and use more chemicals. However, those with the least resources are the most vulnerable to the effects of global climate change; unfortunately, they are also the most likely to be adversely affected by population growth, resource depletion and other forms of environmental degradation. Farmers of developing nations, subject to the above conditions, would never be able to compete in the global market in the face of agricultural subsidies given to their counterparts in industrialized nations.  (Johnson 1991)

The agricultural policies of industrialized nations are designed to diminish the economic gap between its farmers and the rest of its population. In general, trade policies in these nations tend to favor liberalization, but such is not the case with agricultural trade. Industrialized nation's governments provide export subsidies to farmers and place import restrictions on food products in order to increase their producers' profitability in the World Market. These nations justify their interference in the global market on the basis that agricultural trade has such a dramatic impact on a nation's domestic policies and programs. In short, MDCs are primarily concerned with protecting and feeding their own citizens, and their agricultural policies indeed grant their producers a competitive edge.  However, these policies prevent agricultural products from being produced at the lowest possible cost and demonstrate a lack of regard for the producers of other nations, namely those of developing nations. Industrialized nations encourage their farmers to overproduce and to use the international market for further profit. Developing nations, on the other hand, are often forced exploit their farmers. They levy export taxes on food products in order to alleviate foreign debts (such as to the IMF and World Bank), and they force food prices down to accommodate urban consumers and "keep up" with liberalization of the world market. (Thompson 1994)  LDCs suffer for the same "market logic" encouraged by MDCs, though industrialized nations have not themselves liberalized trade in agricultural goods.


There are numerous factors to consider in examining the effect that climate change can have on agricultural systems and world markets.




    To examine the agricultural implications of climate change, we will compile an extensive database of primary and secondary literature regarding agriculture and future change. We hope to conduct ourselves in a multidisciplinary fashion, as agriculture touches upon economic, social, ethical, and ecological issues.  The data we collect will represent a host of different implications for future agriculture given a global warming scenario.  The complexity of agricultural issues and systems does not readily lend itself to statistical analysis, and future uncertainty abounds as far as technological advancement and the inadequacies of current climate change models.  In order to consider the future implications of climate change for agricultural systems, then, it was necessary for us to simplify both the parameters of climate change and of agricultural systems.  We therefore synthesized previous research from a wide array of fields in the context of precipitation and temperature changes and their affects on regional yields currently, and in the future.





This graph illustrates percentage changes in precipitation from 1900 to 1995.


The following climate maps exhibit the change in temperature and precipitation for the next 80 years.  This data was obtained from an IPCC climate modeling program available at their website.  Using the program we inputed the variables for the amount of average millimeters per day and mean temperature in C for precipitation and temperature respectively.


Here are  the projections for future precipitation (mm/day) in comparison for data from 1961-1990.

This graph shows the temperature changes in degrees C for the period from 1900 to 1996.

Here are the projections for future mean temperature in comparison with data from 1961-1990.

This graph illustrates the interaction between climatic factors and the agricultural system.


As part of our research, we chose to divide the world into five regions.  Each region represents an entirely different set of climatic, socio-cultural, economic, and ecological data.  Given this information, it follows that the effects of climate change will differ in each region.  Below are links to the data sets we used for classification and interpretation of regional climatic changes.


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1.  Global dietary patterns What are people eating around the world?

2.  The developing world receives the majority of food aid distributed around the globe.

3.  Developed and developing nations alike depend on agricultural imports.

4.  Many developing nations will lead the world in population growth through the year 2010.

5.  The question remains whether or not developing nations will be able to avert food shortages after climatic change affects their current food production capability.

6.  The economic role of agriculture is likely to increase from current levels as global climate change affects the planet.

7.  The El Nino weather events are also likely to be affected by global climate change.  Changes in the seasonal pattern of El Nino events can disrupt both summer and winter growing seasons.

8.  Those countries with large rural populations are likely to be affected by climatic change.





Given the data we have compiled we chose to examine five regions throughout the globe to determine the potential future changes in land use and therefore agricultural output.

Computer model calculation of the effect of carbon dioxide on plant physiology and global climate. As carbon dioxide increases, vegetation may evaporate less water which would cause the land to heat up (dotted areas). This map shows additional heating (over and above the conventional carbon dioxide greenhouse effect) over the continents due to this phenomenon, for doubled current carbon dioxide concentrations (700 ppm).


This section of the report is a short synopsis of some of the predicted changes and difficulties that each of the five regions may have to contend with.  Given the variability of future climate models and the agricultural effects they would cause, this information is in no way a complete and infallible report.  The primary source of this data comes from the IPCC and the FAO.



In Africa, the most important climatic element is precipitation, particularly seasonal drought and the length of the growing season. The distribution of rainfall within the growing season will affect yields.  High temperatures can affect yields and yield quality in semi-arid and arid regions, although water is more important as a determinant.

Sea-level rise and coastal erosion will affect groundwater, irrigated agriculture, and low-lying coastal land in some areas. The direct effects of CO2 enrichment on plants tend to increase yields and reduce water use. Increased CO2 concentrations increase the rate of photosynthesis and increase water-use efficiency (the efficiency with which plants use water to produce a unit of biomass or yield). The direct effects are strongest for plants with C3 pathways, such as wheat, compared with C4 plants like maize, sorghum, millet, and sugarcane—which are staples for much of sub-Saharan Africa.  Thus, the beneficial effects of increased concentrations of CO2 are likely to offset some of the effects of decreased precipitation.


Regional projections of precipitation change diverge quite strongly in Africa. Thus, for agriculture, there is little confidence in present scenarios for precipitation—the most important aspect of climate change for African agriculture.  The general conclusion is that climate change will affect some parts of Africa negatively, although it will enhance prospects for crop production in other areas.  Some regions could experience temperature stress at certain growing periods—necessitating shifting of planting dates to minimize this risk.  Because a large portion of African agriculture is rain-fed, however, heat-related plant stress may reduce yields in several key crops—such as wheat, rice, maize, and potatoes.  Ultimately, climate change is a global issue—even more so for traded commodities such as agricultural products. Some regions, for example, may be less competitive in national and global agricultural markets, with corresponding impacts on exports and imports. Africa, in particular, may be sensitive to changes in world prices and stocks because many countries rely on food imports.  African economies depend on natural resources, and the impact of changing natural resources affects several sectors of the economy.




Areas are most likely to be negatively affected by climate change: the area around the Great Wall lying southeast of the transition belt between crop agriculture and animal husbandry; the Huang-Hai Plains, where dryland crops like wheat, cotton, corn, and fruit trees are grown; the area north of Huaihe River—including east Shandong—that lies along the south edge of the temperate crop zone; the central and southern areas of Yunnan plateau; the middle and lower reaches of the Yangtze River; and the Loess plateau. Except for the Yunnan plateau, these areas would be at heightened risk of drought and would suffer potential increases in soil erosion. The Yunnan plateau, with generally abundant rainfall, would be subject to alternating drought and water logging, as well as to cold spells, and hence would also suffer yield losses.


Climatic warming would, in general, increase agricultural productivity—partly as a result of reduced periods of low temperature and partly because of the expansion of arable lands.


Adaptive measures—such as changing planting dates, using different varieties of spring wheat, or applying the ideal amount of nitrogen fertilizer at the optimum time—are potential responses that could modify these effects


In China, climate change would occur against a steadily increasing demand for food, which is expected to continue through at least 2050. The increased annual cost of government investment only (excluding farmers’ additional costs) in agriculture in response to climate change through 2050 was estimated at US$3.48 billion (17% of the cost of government investment in agriculture in 1990)




The potential impacts of climate change on agriculture will be reflected most directly through the response of crops, livestock, soils, weeds, and insects and diseases to the elements of climate to which they are most sensitive.  Soil moisture and temperature are the climate factors likely to be most sensitive to change across large agricultural areas of North America. The differential response of species to elevated CO2 concentrations is expected to show a generally positive but variable increase in productivity.

Changes in mean temperature and precipitation will likely affect agricultural crop production. Climate modifications that lead to changes in daily and annual variability in temperatures and, in particular, precipitation also will impact crop yields.

The results of a large number of experiments designed to examine the effects of elevated CO2 concentrations on crops have generally confirmed high confidence in a net beneficial effect of CO2 fertilization.  Changes in soils (e.g., loss of soil organic matter, leaching of soil nutrients, salinization, and erosion) are likely consequences of climate change for some soils in some climatic zones. Cropping practices such as crop rotation, conservation tillage, and improved nutrient management are technically effective in combating or reversing such deleterious effects

Economic welfare may improve for more northerly farm production regions—with potential benefits indicated for the lake states, the northern Plains, the mountain region, and the Pacific region.  Changes in crop production, crop water demand, and regional water resources will arise as a consequence of climate change, although the impacts of these changes on agriculture will be modified by trends in world food production and commodity exports.


Other simulation studies show that corn and soybean yields may decrease across much of the U.S. corn belt with a 2°C rise in temperature (Phillips et al., 1996) and that potato yields may decrease on average by 22% across sites from Maine to Washington as temperatures increase 1.5–5°C.

In general, net welfare will increase.  Increases in precipitation and CO2 increase welfare. Slight-to-moderate increases in temperature also could increase welfare.; increases in CO2 and precipitation could offset the potentially negative effects of large temperature increases.  Climate change appears to be a relatively small stress to agriculture in the United States.




Many countries in the region are highly dependent on agriculture. Land degradation problems and limited water supplies restrict present agricultural productivity and threaten the food security of some countries.   Crop agriculture is highly dependent on irrigation because rainfall is low and highly variable.  There are few projections of the impacts of climate change on food and fiber production for the region.  Little quantitative work has been done on the impacts of climate change on this sector.   However, many of the options available for combating existing problems will contribute to reducing the anticipated impacts of climate change. 

Many countries in the region (the countries of the FSU, Syria, Israel), are highly dependent on local agriculture for food; although some (e.g., Turkey and Kazakstan) are major food exporters, most countries are net importers of food.   Some countries (Tajikistan) rely heavily on imports of grain, both for human consumption and for livestock production.  Land degradation and the consequential need to move to even more marginal lands threaten food security and the economies of countries that are highly dependent on agriculture.

General assessments have suggested a range of positive and negative impacts of climate change on agriculture.  Positive examples include decreasing frost risks and more productive upland agriculture, provided water availability does not decline (or irrigation is available) and appropriate cultivars are used.  Increasing populations of pests and disease-causing organisms—many of which have distributions that are climatically controlled—may have a negative impact . A number of factors affect the vulnerability of agricultural systems: Agro-industry, biomass production, and renewable energy sources depend heavily on climate-sensitive resources and therefore are potentially vulnerable to climate change.


Climate change could have a severe impact on countries that are dependent on single crops.  Diversification of economic activity could be an important precautionary response.

Desertification may occur in any area where the potential evapotranspiration is greater than 70% of the total precipitation—as is the case for parts of this region. It is feasible that desertification itself can exacerbate climate change. Changes in land-use practices can affect surface temperatures through boundary changes in vegetation cover, which lead to differences in albedo and thus to temperature differences




Agriculture is still a key sector in the region’s economy, it occupies an important proportion (30–40%) of the economically active population.  Moreover, agriculture has generated the largest export income in countries having neither oil nor mineral production. In the smaller and poorer countries of the region, agriculture is the basis of subsistence lifestyles, the largest manpower user, and the main producing and exporting sector.


Agricultural production in lower-latitude and lower-income countries is more likely to be negatively affected by climate change.  Climatic variations that result in shorter rainy seasons and/or increased frequency of rainless years would have extremely negative consequences for these regions. However, yield impacts also depend on other factors, such as cultivars and specific environmental conditions.


In Mexico, any shift toward warmer, drier conditions could bring nutritional and economic disaster because agriculture already is stressed by low and variable rainfall. More than one-third of the Mexican population works in agriculture—a sector whose prosperity is critical to the nation’s debt-burdened economy.  Although only one-fifth of Mexico’s cropland is irrigated, this area accounts for half of the value of the country’s agricultural production, including many export crops (Liverman and O’Brien, 1991).


One area that is highly vulnerable to climate change is the Brazilian northeast, which is strongly influenced by the ENSO phenomenon. Years with no rain are frequent; these periods are characterized by the occurrence of famine and large-scale migrations to metropolitan areas



One attempt to reduce the disparity between industrial and developing nations as far as agriculture has been the implementation of food aid programs. Grain Insurance, for example, was designed to minimize yearly variations in food production in developing nations. It aimed to establish a consistent supply of grain to the poorest of the poor, or a sense of food security. (Boonekamp 2000) However, this program and others centered around aid in no way presents  long-term solutions to a nation's agricultural, economic or developmental problems. 


Government protection of farmers is another possible answer; it has proven to raise a nation's per capita income, which is linked with better health care, education, and a decrease in population. (Johnson 1991)  What works in the United States and the European Union, however, may not be an appropriate model of other nations, especially LDCs.  Industrialized nation's agricultural policies attempt to reduce the income disparity between its producers and the rest of its citizens. Agricultural subsidy policies aim to increase demand for farm products and thus increase input into the agricultural sector as a whole, for example, investment in genetic engineering. These policies, though, do not increase the amount of land devoted to agriculture or the sector's total labor force and are responsible for the enormous agricultural surpluses of MDCs.  (Johnson 1991)  Agricultural subsidies become a crutch for the producers of MDCs, and they also create problems for the farmers of LDCs.   In order to compete with the subsidized production and subsidized exports of other nations, while simultaneously attempting to increase productivity and cope with the negative effects of climate change, farmers in LDCs may turn to negative environmental practices.  In the light of economic globalization and the emergence of the world market, MDCs should develop and agree on agricultural policies that consider the disparity between the world's producers and the world's citizens and the income disparity between agricultural labor forces of MDCs and LDCs.


Attempts have been made at several GATT and Uruguay Rounds to negotiate freer trade in agricultural products.  (Foster and Leathers 1999)  However, few nations are willing to reduce protection by removing subsidies on both production and exports, and so the attempts have been more or less futile.  Some nations have conceded to reduce or remove import taxes and restrictions, but these are mainly LDCs.  If progress is to be made in agricultural policy, it is crucial that both the United States and the European Union agree to some reduction in subsidized production or to world market commodity prices.  Aid to LDCs should also be gradually reduced, and directed primarily at improving public rights and infrastructure. Aid could also be directed at subsidized consumption (both domestically and) in LDCs.


Developing nations ultimately need what the EPA's Office of Research and Development (ORD) has classified as Enabling Tools for Sustainability: Analytical Tools for problem identification, analysis and decision-making, Process Tools for problem-solving and technological advancement, and Economic Tools to build a supportive infrastructure for financial analysis and investment decisions.  (  They need their own capital for research into climate change, resource protection, and agricultural productivity, not merely conditional aid from hegemonic institutions.  The producers of the world should be empowered by political and economic systems, not "rescued" and forced into unrelenting debt and poverty.  





Intergovernmental Panel on Climate Change

    The U.N. Food and Agriculture Organization


The U.S. Global Change Research Center


Environmental Protection Agency">Global Change Data and Information Center

Click here to create your own climate scenario as we did earlier in the presentation.




To access a complete list of our works consulted and cited click here.  It includes the citations, a brief abstract of the materials, and the reason we chose to include it.


For access to a folder with our articles in PDF format click here.


The future of our agricultural system and human life as we know it may very well depend on the choices we make today.

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