A cool October broke a 16-month streak of above average temperatures across the Lower 48, but temperatures are projected to remain above normal across most of the western half of the country in the coming months. In addition, the latest climate change projections put future temperature gains on the high side of various models.
As of November 6, 59.5 percent of the contiguous U.S. was experiencing persistent drought conditions that are most severe in the Great Plains—North and South Dakota, Nebraska, Kansas, Oklahoma, Texas, Montana, Wyoming and Colorado—where drought is expected to persist or intensify in the foreseeable future. On October 17–18 those drought conditions combined with high winds to create a large dust storm across Colorado, Nebraska, Kansas, Oklahoma and Wyoming, closing major highways.
To Katharine Hayhoe, professor and director of the Climate Science Center at Texas Tech University in Lubbock, this heralds big changes for agriculture on the Great Plains. "In a nutshell," Hayhoe says, "we're seeing major shifts in places and times we can plant, the types of crops we can grow and the pests and diseases we're dealing with. If you talk to seed companies, the U.S. Department of Agriculture (USDA) and even farmers, they tell you we can modify our way out of this, that we can overcome all these problems with technology. There's no question we can adapt to some of the change, but whether we can adapt to all of it is a very open question."
In the 1930s Dust Bowl a land speculator– and government-encouraged plowing frenzy removed windbreaks and grasslands that stabilized soil. The dry, windy weather that followed created one of the worst man-made ecological disasters ever. Powerful winds scoured bare soil from the ground and carried it long distances. Farms failed across Colorado, Kansas, Oklahoma and Texas.
This October's dust storm, which followed preparation of fields for fall planting, could be the first act of an encore performance. "If the drought holds on for two or three more years, as droughts have in the past, we will have Dust Bowl conditions in the farming belt," says Craig Cox, an agriculture and natural resources expert with the Environmental Working Group, a nonprofit using public information to protect public health and the environment. "It could be in a sense an invisible Dust Bowl—not like the big storms before, but withered crops, dry streams and other disasters that accompanied the Dust Bowl. Wind erosion is tremendously damaging and hard to control. A lot of practices that control wind erosion require growing things, and if those weren't in place when the drought hit, it's almost impossible to put them in place now."
Since the 1940s agriculture on the semiarid southern Great Plains—Colorado, Kansas, Oklahoma and Texas—has relied on irrigation. On the high plains of Texas, tens of thousands of wells pumping from the 10-million-year-old Ogallala Aquifer have depleted it by 50 percent. Given variation in its depth and the difficulty of pumping at low water levels, most of the remaining reservoir will likely be useless for irrigation within about 30 years. At the same time, climate change has brought less rain as well as hotter temperatures that increase evaporation—forcing farmers to use even more water for irrigation. "We have agriculture systems in semiarid areas," Hayhoe says. "We built these vulnerabilities into the system and climate change is the final straw that may break the camel's back."