Just One Degree Of Warming Could Cut One-Fifth Of Kansas’ Wheat Production

CREDIT: Brian McGuirk / Flickr


CREDIT: Brian McGuirk / Flickr

It looks as though an increase in temperatures for the Great Plains region of just one degree Celsius could cut down wheat production in Kansas by over 20 percent. Even under optimistic scenarios, the region is probably headed for three times that amount of warming by the end of the century, making Kansas a microcosm for the damage carbon emissions will do to human society.

The researchers from Kansas State University actually carried out a three-pronged inquiry: to determine the effect of not just climate change, but also of disease and genetic improvements on the state’s wheat production. They looked at Kansas performance tests of wheat yields, as well as location-specific data for disease, weather, temperature, solar radiation, and even vapor pressure from 1985 to 2011. They then built computer models based off that data to tease out the effects.

On climate change specifically, the researchers found that a one degree Celsius increase in temperatures for the area would cut wheat yields by 10.64 bushels per acre. Since the mean yield for 1985 to 2011 was 50.59 bushels per acre, that comes out to a 21 percent decrease. And three degrees of warming would cut yields by 32.36 bushels per acre, or a whopping 64 percent.

To put that in context, take a look at this video of temperature projections for the United States, which NASA based off the latest National Climate Assessment. It shows that hitting atmospheric carbon dioxide levels of 550 parts per million (ppm) by 2011 warms the Great Plains region by 2 degrees Fahrenheit in 2040 and 6 degrees in 2080. In Celsius, that translates to 1.1 degrees in 2040 and 3.3 degrees in 2080.

Now, the two projections don’t match up perfectly. The video shows warming starting from the average annual temperature from 1970 to 1999, while the Kansas State University study started its projections at the mean temperature for 1985 to 2011. But you get the gist: by 2080, global warming could reduce Kansas’ wheat yield by as much as two thirds.

And that’s the optimistic scenario. Unless the world gets serious about reducing carbon emissions now, we’re going to blow past the 550 ppm mark. And as the video shows, 800 ppm by 2100 delivers 3.3 degrees Celsius of warming by just 2050 and around 5 degrees by 2080.

On top of all that, another Kansas State University team recently determined that the combination of farming and beef production has already sucked up 30 percent of the High Plains Aquifer, which supplies the water for Kansas and the rest of the Great Plains region. At the present pace, another 39 percent will be depleted in 50 years. That means pumping gets more expensive, while farming becomes ever less profitable.

Now, the new study also found that breeding programs increased Kansas’ wheat yields by nearly 21 percent over the 26 years the research covered. But it would have to maintain that pace of improvement for the next three decades just to keep up with the yield cuts from one degree of warming. So genetic advancements can help, but they’ll be far from adequate under the most likely scenarios of climate change of water depletion.