AGCI Session II: Characterizing and Communicating Scientific Uncertainty
Session Chairs: Dr. Richard H. Moss and Dr. Stephen H. Schneider
July 31 to August 8, 1996
Climate Effects on Food Security
Robert S. Chen
Consortium for International Earth Science Information Network (CIESIN)
University Center, Michigan
Our understanding and ability to project future climate effects on food security are still very primitive, Chen says. There have been few international assessments, and very few coherent efforts to pull all the available information together. Only two trade models have been used to address integration of various possible impacts in an international trade framework. There is very limited research to draw upon in trying to link climate factors to impacts on the larger food system and overall food security.
Food security issues are of interest to a wide range of decision and policymakers. Climate change is but one contributing factor. What is the decision framework? What else must be considered besides climate? How do climate uncertainties compare with other uncertainties? There is a great need to better understand the context and the decision framework.
Chen disagrees
with the assumption that the developed world is not vulnerable to
climate change impacts on food security.
Dimensions of Food Security
Chen disagrees with the assumption that the developed world is not vulnerable to climate change impacts on food security. There is much legitimate concern about water and land resources, such as limitations on agriculture and competition for land. There are also a whole set of food access issues, such as the sociopolitical nature of many famines. Chronic undernutrition affects on the order of 1-2 billion people, and nutrient deficiencies plague many more.
Conventional projections of world hunger (not including possible climate impacts) expect some improvement in the hunger situation over the next few decades. However, in Africa, for example, even if percentages decline, absolute numbers of people in hunger may still increase. Links between hunger/food access and poverty and efforts to break these links are issues of concern, as is the basic human right to food. Even in the developed world, this right is not firmly established programs such as food stamps are always under attack. In other instances, food is used as a weapon of war.
Food utilization is an understudied area. Beyond basic questions of population and yield, there are issues of dietary preferences (such as the increasing use of animal products), cultural issues, caloric needs of people in various occupations, and rural versus urban diets. Health and disease issues also enter into the equation. For example, parasites affecting about a billion people cause losses of 10-20 percent of the calories they eat. There are also potential links to climate change of cholera and other diseases that affect nutritional status. A more general issue is the diversion of food to non-nutritional uses including pet foods, tobacco, biomass energy, and the creation of diet foods that can't be digested. Food storage and waste comprise another area of concern.
Figure 2.6 illustrates possible links between future food security and the occurrence or prevention of possible global environmental changes. Chen believes that food security is an important normative issue; the world can decide that food is a basic human right and take steps to implement that view. He also mentions the fact that there may be cultural biases in research agendas, for example, the relatively late attention given to rice which feeds a third of the world's population in terms of possible climate impacts.
Regarding uncertainties in the decision making framework, Chen asks, "what does this all mean for agriculture now?" While there may be legitimate concerns about the potential effects of future climate change on the food system, many people are hungry now. What are the near-term food security impacts of proposed climate change mitigation strategies? For example, if a fossil fuel tax is implemented, it could change the current vulnerability of the food system and present -day access to food. This implies significant change in the system we're now trying to assess.
With regard to the decision making framework, Chen recalls the 1991-92 drought in southern Africa and the fact that it was predicted by using an El Niño/Southern Oscillation index. While information about this prediction was just beginning to surface and the drought was developing, in November of 1991 the World Bank urged Zimbabwe to make a large grain sale in exchange for a loan from the World Bank. Zimbabwe acquiesced to the Bank's request and, ironically, then used the loan to import needed food at higher prices due to the drought. The predictive information was not put into a form that was useful in a timely manner to the people who needed it.
Human population is a key issue to consider when looking at possible climate effects on the food system. It is important to remember that the United Nations' median projection is the middle of a very broad range of possible future human population sizes. Demographers make little attempt to analyze the probability distribution of the low, medium and high scenarios. Chen once tracked the history of past UN population projections for Africa and found that the current population estimate for Africa is now somewhat above the range of past projections. It is important not to take UN population projections for granted, but to study demographic models more critically. For example, one of the limitations of the UN's methodology is that the projections for future African fertility do not follow the "S" curve evident in the historic demographic transitions of other world regions.
While there may
be legitimate concerns about the potential effects of future climate
change on the food system, many people are hungry now. What are the
near-term food security impacts of proposed climate change mitigation
strategies?
Chen believes that if we limit ourselves to a simple "linear" perspective on food supply, we will end up having to choose the least of a number of evils. Food security is a broad issue for which there exists a wider array of options than is commonly perceived. Options include addressing food distribution, nutrient deficiencies, and eliminating war's effect on access to food. The IPCC process could begin to address this larger set of options.
In conclusion, Chen points to the continuum of decisions that are made in the food system, from local to national to global and from short to long term. There is a need to look beyond current decisions to future ones. We should also look at the robustness of decisions relative to uncertainty, and take actions that will be appropriate regardless of the outcome. Further, we must not forget about the possibility of surprises. For example, the current news about an unexpected die-off of honey bees is a reminder that we do not control everything and often cannot predict all outcomes.
Food security is
a broad issue for which there exists a wider array of options than is
commonly perceived. Options include addressing food distribution,
nutrient deficiencies, and eliminating war's effect on access to
food.