Check it out: The arid west is expanding

By Sonia A. Hall

One image of cows grazing and one image of row crops
Landscapes west and east of the 100th meridian. Left: Rangeland country in Idaho. Photo: Sonia A. Hall. Right: Soybean crops in Iowa. Photo: Parshotam Lal Tandon, under CC BY-NC-SA 2.0.

The contrast between the arid west—rangelands, wheat, conifer forests, irrigated agriculture—and the Midwest’s Great Plains—corn, soybean, prairies—is well known. There is a somewhat abrupt line separating arid from humid, close to the 100th meridian. That line is now shifting, as climate change affects temperatures, precipitation, and wind patterns that control that arid-to-humid line. Take a look at a recent study from Columbia University on how the line is shifting eastward from the 100th meridian. And you might want to start with the blog article “The 100th Meridian, Where the Great Plains Begin, May Be Shifting.

References:

Seager, R., N. Lis, J. Feldman, M. Ting, A.P. Williams, J. Nakamura, H. Liu, and N. Henderson, 2018: Whither the 100th Meridian? The Once and Future Physical and Human Geography of America’s Arid–Humid Divide. Part I: The Story So Far. Earth Interact., 22, 1–22, Online Access 

Seager, R., J. Feldman, N. Lis, M. Ting, A.P. Williams, J. Nakamura, H. Liu, and N. Henderson, 2018: Whither the 100th Meridian? The Once and Future Physical and Human Geography of America’s Arid–Humid Divide. Part II: The Meridian Moves East. Earth Interact., 22, 1–24, Online Access