Climate Science Library

The Climate of Food

Caroline Ailanthus, USA

Food depends on climate. Intellectually, most of us know this, but the link between planet and table can be hidden by the convenience of the grocery store. It’s easy to forget that when the climate we are used to change, the food availability we are used to change as well. Predicting food security is not simple. To some extent, changes in growing conditions can be predicted, but how much food is available also depends on land use patterns, agricultural practices, distribution patterns, and the size of the human population. For any given scenario of warming, how many people will go hungry, and which people go hungry, depends on the decisions we make, both individually and collectively, now.

Generally, the prediction is for temperate areas to see yields rise initially. Many plants (though not corn) grow faster when given more carbon dioxide, and temperate growing seasons are lengthening. Tropical areas will see yields shrink, due to more frequent droughts. Overall, there will likely be a net yield decrease proportionate to the warming we experience. At the same time, the human population will likely continue to grow for several more decades at least, meaning we will need more food than we do now. To what extent new farming practices and other issues will influence the food supply is impossible to say.

Human food security is not simply a product of yield and area cultivated. However to be eaten, food must not only be produced, it must also be delivered to the eater. Distribution is governed by national and international policy, and by market prices. A tightening of supply manifests first as rising food prices, progressively pricing food out of the reach of poorer people at a fairly predictable rate. What is not predictable is whether riots, or even wars, over food distribution will cause further shortages or other problems.

Discussing climate change predictions can make it seem as though we face some impending, sudden apocalypse, as though we are going to wake up one day and find global warming, at last, upon us. Actually, we have been causing climate change for decades already. We have warm days and cool days, and wet days and dry days, as we always have, except that we gradually trend towards warmer more extreme weather patterns. This variability both hides the change we are experiencing and makes it more dangerous. A slight increase in bad weather can be decisive, since even one day in a season that a crop cannot survive destroys the whole season.

When we talk about the impacts of global climate change, what that means in practice is an increasing likelihood of local, apparently separate disasters, none of which can be predicted specifically. So what does this look like for the United States? Our crops will likely do fairly well, at least initially, because our climate is temperate. Our corn yield may fall somewhat over the next few decades, but much of our corn is either exported or fed to animals. Adjusting our production to new conditions should not be difficult.

The more serious problem is that America now imports much of our food. We are dependent on a global distribution network, and instability anywhere in the system influences American food prices. Beyond issues of food production, however, are both transportation and politics, and neither is easy to predict. Distribution depends on transportation infrastructure. We saw this past summer that infrastructure is vulnerable to weather; floods take out roads. The Northeast could get up to 20% wetter over the next eighty years, meaning that the flooding we saw in Vermont and New York will likely become more common. Without certain key bridges, food does not move in or out of New England.

Distribution also depends on energy. Without fossil fuel, very little food moves in and out of the United States as a whole, and fossil fuel will likely get more expensive in coming decades as we move through peak oil. Food will get more expensive correspondingly. Distribution also depends on social order, which may break down as people in tropical regions grow desperate for food and water. Although yield losses in the tropics could be balanced to some extent by yield gains in temperate zones, remember that changes in growing regions will not manifest as a gradual shift, but as increasingly common and severe crop failures, which will then strain political relations. A regional resource war could, for example, increase the price of oil dramatically, spiking U.S. food prices, even if no one in the U.S. expected to eat any of the crops that failed.

If our vulnerability comes as a surprise it is not because the information is not available; major newspapers, magazines, and websites report on the direct and indirect implications of climate change, including food vulnerability fairly often. If the seriousness of the problem is not at the center of the national agenda, where it should be, it is not because information is missing but because habits of thinking are. As a nation, we have lost the habit of thinking about the links between ourselves and the planet. It is a truism that we no longer live on the land as our ancestors did, that we are somehow far away from nature, but the truism is false. The truth is we will never live anywhere but on the land, and we can’t get far away from nature; the laws of ecology have world-wide jurisdiction just like the laws of physics do.

We drink nature, we breathe nature, and we eat nature. If something goes seriously wrong with nature, we will no longer be able to eat. But how can we think clearly about the connections between planet and plate when supply chains stretch across the globe, and sometimes back again? The prices we see in the grocery store are vulnerable to crop failures and labor disputes in countries, most of us know very little about. Simplifying the food system by buying locally would again make it easier to think responsibly about what we buy. Local eating would get some of the petroleum out of our food, although transportation only accounts for about 15% of food-related greenhouse gas emissions (according to a recent study, even a small reduction in the use of red meat would reduce emissions more than locavorism can). Local food distribution systems would not prevent areas with a surplus from selling, or even donating, to areas without enough food. Food export may become very important to temperate zone countries in the coming decades. Certainly, regions within the United States, or even the United States as a whole, may be very glad to get food from elsewhere in some years. But if each area takes responsibility for feeding its own people, then our economic system will be able to distribute food security as needed, instead of distributing food insecurely.

Local eating begins with consumer demand, but it should not end there. Current trade law favors global supply and distribution chains to the point that local producers often cannot compete with food grown on the other side of the planet. Public policy could favor local food production, but largely does not. Public schools could lead the way by using locally grown food into school lunches; some schools have done this, even incorporating food issues into science curricula. Unfortunately, such programs still have very little policy support. It is possible we will not run into catastrophe in this country; plausible scenarios are not prophesy. But it is also possible that we will be in real trouble. Our country can adapt to global climate change, and as a major industrial power, we can do a great deal to make sure that the climate does not change much more to begin with. We can do neither on a dime. If we do nothing until the food supply starts to break down, then Americans will get hungrier. And hungry Americans will have a reason to be very angry.