Climate Change Is Already Shrinking Crop Yields

For years now, people have wondered how climate change will affect farming. How will humanity feed itself during a time of rising temperatures and recurring drought?

July 4, 2012 | Source: Mother Jones | by Tom Philpott

For related articles and more information, please visit OCA’s Genetic Engineering page, Millions Against Monsanto page, and our Organic Transitions page.

For years now, people have wondered how climate change will affect farming. How will humanity feed itself during a time of rising temperatures and recurring drought?

Here in the US, we’re starting to get a taste of things to come-and it’s bitter. Brutal heat is now roiling the main growing regions for corn, soy, and wheat, the biggest US crops. According to Bloomberg News, 71 percent of the Midwest is experiencing “drier-than-normal conditions,” and temperatures are projected to be above 90 degrees in large swaths of key corn/soy-growing states Missouri, Illinois, and Indiana through July 7 if not longer.

As a result, Goldman Sachs projects that this year’s corn yields will come in 7.5 percent below the USDA’s projection of 166 bushels an acre. (Why is a Wall Street behemoth like Goldman Sachs fussing over corn yields? That’s another story, altogether, and an interesting one). Accordingly, crop prices are rising steeply, Bloomberg reports.

Of course, we can’t tie any individual heat wave to long-term climate trends-there’s plenty of random weather variation even in times of climate stability. But we do know that hot, dry weather can stunt plant growth and reduce yields-and we also know that we can expect more hot, dry weather in key growing regions as the climate warms up.

I hope the current heat wave gets policymakers thinking about the effect of climate change on food, because for for a long time, the consensus was that global warming might be more or less neutral for agriculture. Sure, the thinking went, climate change will likely make droughts more common and make some already-hot areas too hot for farming; but it will also lengthen the growing season in cold-winter areas like the US Midwest, perhaps increasing crop yields. Also, all that carbon dioxide we’re pumping into the atmosphere by burning fossil fuels would be manna to plants, allowing them to grow faster. These factors, many thought, would largely cancel each other out, and mean that climate change would have no great effect on global food production.