Tutorial: Global Warming And The Future Of Agriculture

October 19th, 2011 | No Comments
Climate Change, Okeanos Tutorials, The View From Lazy Point

Adapted from: 2011. The View From Lazy Point. Henry Holt Co.  New York.

Out of about 300,000 named plant species, we get 90 percent of our food from just 103 species, and we get 70 percent from just three: wheat, corn, rice. But—between 200,000 and 400,000 varieties of rice exist in the world. Some grow on land, some under fifteen feet of water. Sixty thousand kinds of beans include some that resist heat, others that resist bugs.

Dug into a mountain in the high Arctic, at a place called Svalbard, is the “Doomsday Vault,” the world’s safety deposit box for seeds, humanity’s cold-storage for agriculture. More formally it’s the Global Seed Vault, established in 2008 by the Global Crop Diversity Trust. The location was chosen because it is likely to remain insulated and isolated.

Warming is why it’s in so cold a place.

Curly-haired Cary Fowler has come to this land where there is no farming, to save the future of agriculture. His job is to collect, preserve, and store samples of as many crop varieties as possible, so that agriculture might be able to adapt to the warming world.

“Twenty years from now,” Fowler says, “the climate in some countries won’t be anything like it is now.” He shows me a graph that plots growing-season temperatures in India for the past century, and temperatures projected by the end of this century. During the growing season, the past and projected temperatures do not overlap. There’ll be an entirely new range of temperatures. Concludes Fowler: “Agriculture has never seen the kind of climate that is coming.”

That throws food forecasts into question.

Corn needs rain. Forecasts for coming years predict worsening African droughts. And if a corn stalk’s silk dries out, you get no corn.

“If you look ahead, and factor in climate,” Fowler says, “you’d predict a 30 percent decline in corn in South Africa. That’s total yield, not per-person.” You’d have to take the thirty-percent-less total yield, and divide that by the number of people expected due to population growth, to really see how much less food per person is likely.

Corn’s not the only concern. About half the world’s population eats a bowl of rice every day. Rice pollination success is nearly 100 percent at roughly 95º Fahrenheit (34º C). Rather stunningly, for every added one-degree-Celsius rise in nighttime temperature, rice yields drop ten percent. At about 105 Fahrenheit (40º C) it fails almost entirely. Similarly, for each one-degree-Celsius rise in temperature, corn and wheat yields decline about five percent. The National Academy of Sciences says, “Temperature increases due to global warming will make it increasingly difficult to feed Earth’s growing population”

“Is agriculture ready?” Fowler poses. His answer: “No.”

References and Further Reading:

Yield declines in grain: Peng, S., et al., 2004, “Rice Yields Decline With Higher Night Temperature From Global Warming,” Proceedings of the National Academy of Sciences 27: 9971-9975.

Difficult to feed Earth’s growing population: National Academy of Sciences, 2004, “Warmer Evening Temperatures Lower Rice Yields,” Proceedings of the National  Academy of Sciences News Archive, June 28 – July 2.

Reduced corn and soybean yields with increasing temp: Lobell, D. B., and Asner, G. P., 2003, “Climate And Management Contributions To Recent Trends In U.S. Agricultural Yields,” Science 299: 1032.

Sorghum seeds viable up to 20,000 years: Anonymous, 2008, “Arctic ‘doomsday’ seed vault opens doors for 100 million seeds,” ScienceDaily, available online.

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