Climate change and the food supply: it's not going to get any easier

Corn, wheat, rice and soy tend to suffer in extreme heat

Martin LaBar/Flickr

Kate Lunau is covering the 2012 annual meeting of the American Association for the Advancement of Science in Vancouver, a gathering of some of the world’s finest brains and celebrities of science. On Feb. 16-20, Lunau will bring you a sneak peak of the latest research and findings, posting to on anything from healthcare and climate change, to food security, and more. Follow Kate on Twitter:@Katelunau , #AAAS, #AAASmtg.

On Saturday morning at the AAAS Meeting in Vancouver, scientists were talking about the implications of a warming world. As part of one symposium called “Make it Fit,” looking at how to support a decent standard of living for our planet’s growing population, I caught a talk from economist Michael Hanemann about how water demands will shift due to climate change. Already, he said, there are 2.8 million deaths per year due to contaminated water. But scarcity isn’t the main problem; access is, and that requires plumbing to bring the water to people, which can be expensive.

Climate change is expected to cause “more intense episodes” of precipitation, Hanemann noted, which will require better ways to store the water when it falls, but that costs even more money. In California, he said, most precipitation happens in the winter, but three-quarters of water use happens in the summertime; snow is an important way to store it through winter months, saving about one-third of precipitation for use later on. But as the climate warms, and rain falls instead of snow, that will change—not just in California, but in Canada too, of course.

After that came a fascinating briefing from four experts on the emerging risks to the global food system. Wolfram Schlenkerpointed out that corn, wheat, rice and soy make up 75 per cent of our calories, but these crops tend to suffer in extreme heat above 30C. Thanks to modern farming methods, yields have increased threefold over the last fifty years, he said—but their sensitivity to heat remains about the same. As climate change continues, that will have some serious implications for our food supply, as will changing lifestyles in developing countries and the growing number of people consuming higher-calorie diets and more red meat, which will also squeeze the food supply. Any climate change, he said, “will have a really significant impact worldwide.”

Of those four foods that make up three-quarters of our diet—corn, wheat, rice and soy—a whopping 23 per cent of them are produced in the U.S., three times bigger than Saudi Arabia’s oil production, Schlenker said. The use of corn in ethanol production creates a “massive impact on demand,” he continued. “This is not necessarily a good thing considering the impact on world food prices.” A debate of sorts broke out between Schlenker and other panel participants on this point. Roger Beachy agreed there was reason for concern about using a food source for ethanol production, and said he “would like to see it otherwise,” but also pointed out that it gives farmers more choice, and contributes to economic stability. But with a few factors constricting the food supply, Schlenker said, “who’s going to suffer is the consumer.”