Earth Interactions map
The boundary was at 100 degrees west longitude when American geologist John Wesley Powell identified it in 1878. The meridian roughly marks the eastern boundary of the sparsely populated Great Plains. Wheat grows well in the west, but east of the boundary, thirstier crops like corn thrive.
Richard Seager, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory and the study's lead author, "predicts that as the line continues to move farther east, farms will have to consolidate and become larger to remain viable," Rice reports. "And unless farmers are able to adapt, such as by using irrigation, they will need to consider growing wheat or another more suitable crop than corn."