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Of all the uncertainties climate change presents, its impact on the production and distribution of food is one of the greatest. We are already feeling the effects: 2012 was a bad year for farmers, with droughts and erratic weather decimating crops and pushing up global food prices. Food prices are at historic highs and there have been two global food crises in the last five years leading to riots in Haiti in 2008 and contributing to the Arab Spring in 2011.
Molly D. Anderson and John Reilly examine the complex challenges and trade-offs humanity faces in a world where climate change is upending traditional assumptions about where and how we can produce enough food for the world's rapidly growing population.
Molly D. Anderson is a professor at College of the Atlantic and holds the Patrtridge Chair in Food and Sustainable Agriculture Systems.
Until just a few years ago, there were some blithe assumptions about how climate change would affect food security: Like migrating birds, agriculture will simply move north to escape extreme heat, and only food production will be affected by climate change.
Today we recognize that it's not just temperature, but a whole set of complex interrelated factors — temperature, rainfall, timing, soils, practices throughout the food system and more — that are affected by climate change.
Each crop has its own ideal set of circumstances. Having too many warm nights can be deadly for some crops. Not having enough hours of nighttime freeze can hurt others. Human societies have evolved with agriculture over the last 10,000 years to use particular crops in particular places. Now we're experimenting with drastic changes in a matter of decades.
Human societies have evolved with agriculture over the last 10,000 years to use particular crops in particular places. Now we're experimenting with drastic changes in a matter of decades.
It's not going to be easy, for a number of reasons, for agriculture to just move north. Farming is one of the most place-based occupations in the world. Farmers won't easily pick up and move north. If they do, the soil they'll find will be completely different.
Climate change isn't just affecting the production of food; it's also affecting consumption of and access to food. Ocean acidification will lower fish catches, which in turn will increase demands on land-based foods. Climate refugees will need new access to food, yet will be unable to produce their own. Food safety will become more challenging.
Food security, as defined by the Food and Agriculture Organization of the UN (FAO), is "when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life."
Even without climate change, with the growing world population, food security will present a challenge. We need to look for win/win solutions — ones that improve food security and sustainability of food systems on the one hand and that mitigate and adapt to climate change on the other.
On the farm level, this means promoting the use of renewable energy in food production, restoring degraded soils and diversifying crops.
On a state and regional level, it means first recognizing food as a basic human right and then making policy decisions that flow from that recognition. For example, using land to produce food would take priority over using land to produce biofuels or animal feed; and states and regions would establish adequate food reserves and be able to set their own food and trade policies. States and regions must promote energy and water efficiency throughout the food system as well.
Globally, we need to slow population growth. One of the most effective ways to do that is to educate girls and women and provide access to contraceptives. We also need to reduce food waste and over-consumption, particularly by wealthy people and nations of the world.
When it comes to food security, the developed world is answering the wrong questions. We’ve focused on increasing availability of food and “feeding the world” (to the benefit of our own corporations). We need to focus on improving food access, reducing our own over-consumption, and addressing why poor people can’t feed themselves in a world with more than enough food for all its inhabitants.
John Reilly is senior lecturer and co-director of the Joint Program on the Science and Policy of Global Change and a senior lecturer at the MIT Sloan School of Management.
Since 1980, the world's breadbaskets — areas where major crops like maize, wheat, rice, and soy beans are grown — have warmed significantly. Interestingly, the U.S. is the major exception to this global trend. Our agricultural regions have actually experienced somewhat cooler temperatures overall — with a few exceptions.
The effects of climate change on agriculture are likely to be mixed, benefiting crops in some areas and harming crops in others. In colder regions, like New England and much of Canada, growing seasons are becoming longer. We can expect lower crop yields in regions where heat exceeds critical thresholds.
Just as agriculture is a major cause of greenhouse gas emissions, it could also play a major role in mitigating climate change.
Scientists estimate that doubling CO2 concentrations from pre-industrial levels would increase crop yields by as much as 20 to 30 percent, but would also increase the growth of weeds. Furthermore, the increase in crop yields from the effects of more carbon dioxide in the air would largely be offset by the effects of increased temperatures and decreased soil moisture.
Agriculture and climate are both highly complex pieces of the Earth's ecosystem. Constructing reasonably accurate, useful models of how the two interact is an enormous scientific challenge.
My colleagues at MIT and I have begun developing a model for predicting crop yield changes in the world's breadbasket regions. We've found wide variations in how yields are likely to be affected by climate change. Generally speaking, whether we looked at maize (corn) in North America and West Africa, wheat in Europe and Asia, or soybeans in South America, the results were the same: Areas closer to the equator saw declining yields, some up to 50 percent, while areas closer to the North and South Poles showed increased yields. They balance out at some level, but this kind of change would cause lots of dislocation.
With global population projected to peak at 10 billion sometime after 2050, and with rising incomes allowing more people to eat a resource-intensive diet (i.e. eating more meat), we face great agricultural challenges even without the dislocation and disruption climate change will cause.
Just as agriculture is a major cause of greenhouse gas emissions, it could also play a major role in mitigating climate change. Our studies show that an aggressive global reforestation policy could result in a half-degree Celsius of avoided warming by 2100. The key would be putting a price on carbon for removing carbon dioxide from the atmosphere. This price would create an incentive for landholders to reforest their land, because forests are great absorbers of carbon.
Reforestation comes at a cost. More land for forests means less land for agriculture. That means we could expect to see higher food prices, especially for livestock.
This is part of the trilemma of what to do with land in the 21st century. Do we use it to produce biofuels as a substitute for fossil fuels? Do we use it to produce food? Do we use it to preserve biodiversity and store carbon?
There are unavoidable trade-offs no matter what we decide. There are no easy solutions when it comes to climate change and food security. What is clear is that the worst "solution" would be continued inaction in the face of the overwhelming evidence that climate change has real and growing effects.
This program aired on April 15, 2013. The audio for this program is not available.
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