How will climate change affect the world food system?

I wrote this article for the blog of the International Food Policy Research Institute (IFPRI), celebrating its 40th anniversary. The goal was to present a key research topic through the years from the personal perspective of the researcher. This article appeared May 4, 2015. Below, I present a few key paragraphs, and a link to the full article. — Tim Thomas

Long before I joined IFPRI, I served in the U.S. Navy. One of the first lessons I learned in my naval training was how to avoid running into − or being run into by − another ship. You would think it would be pretty simple to avoid, but the trouble is that ships don’t turn very fast nor do they stop instantly. What’s more, on the ocean there are no lane markings to keep ships separated (except for buoys in channels). It turns out that without a simple rule of thumb, keeping two large vessels on different trajectories from running into each other isn’t always straightforward. Fortunately for ships, such a rule exists: if the other ship is on a constant bearing relative to your position and the range is decreasing, you’re going to collide unless somebody changes course or speed − and generally speaking, the sooner the better. Keeping your focus in the right place helps you figure this out.

It’s similar in regard to determining how climate change will affect the world food system. Many things are moving in different directions and speeds at the same time and, if you focus on the wrong thing, you’re going to draw the wrong conclusion. For example, we use crop models together with climate models to determine how much production is going to be hindered by the changing climate, all other things being equal. We generally find that the direct climate impact is negative and sometimes quite large. For example, some of the models suggest that climate change will reduce the productivity of corn in the U.S. by up to 40 percent by 2050. Since the U.S. is the leading corn producer, and since other major producers should be similarly affected, this is a big deal. Focusing on this number, however, as some people do, would lead to a very frightening conclusion. Add on top of that an expanding global population that will be a third larger in 2050 than it is today, and you would think that global food security is in an even more dire condition.

Yet what has been overlooked in all of this is the fact that maize yields have grown globally around 2 percent per year during the past forty years, without a sign of slowing down — and this is all despite the impacts of climate change already being felt. Furthermore, maize production in the last 20 years has grown even faster − at 3 percent per year − because expanding yields also have coincided with expanded harvested area. So while climate change creates a tremendous drag on what could have been − the yields we would experience without climate change − agricultural productivity gains due to technological innovations such as high yield maize varieties and nitrogen-based fertilizers together with expanding production areas have compensated. They will most certainly continue to compensate in the future, though probably with less effectiveness as the intensity of climate change grows.

Continue reading at the IFPRI blog

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