Adapted from: Global Climate Impacts in the United States. T.R. Karl, J.M. Mellilo, and T.C. Peterson (eds.). Cambridge University Press, 2009. Available online at USGCRP
Over the last few decades, average temperatures have risen throughout the Great Plains, with the largest increases occurring in the winter months and over the northern states. Relatively cold days are becoming less frequent and relatively hot days more frequent.
In the future, temperatures are projected to continue to increase with larger changes under scenarios of higher emissions of heat-trapping greenhouse gases. Summer temperature increases are projected to be larger than those in winter in the southern and central Great Plains. Precipitation patterns are also expected to change, particularly in winter and spring. Conditions are expected to become wetter in the north and drier in the south. Projected changes include more frequent extreme events such as heat waves, droughts, and heavy rainfall.
Key issues for the Great Plains include:
Projected increases in temperature, evaporation, and drought frequency could stress water resources. Most of the region’s water comes from the High Plains aquifer, also known as the Ogallala aquifer. Rates of water withdrawals already exceed recharge rates in the Ogallala. Rising temperatures, faster evaporation rates, and more severe drought brought on by climate change will add more stress to overtaxed water resources.
Agriculture, ranching, and ecosystems will face stress from increasingly limited water resources and rising temperatures. Agriculture covers 70 percent of the Great Plains. As temperatures continue to rise, the optimal zones for growing certain crops will shift. Pests will spread northward, and milder winters and earlier springs will encourage greater numbers and earlier emergence of insects. Although the climate is expected to become wetter in northern areas, projected increases in precipitation are unlikely to offset decreasing water availability due to rising temperatures and groundwater depletion from ongoing well withdrawals.
Changes in key wetland habitats could create challenges for native plant and animal species. Climate change is likely to combine with other human-induced stresses to make prairie potholes and other wetland ecosystems more vulnerable to pests, invasive species, and loss of native species. Breeding patterns, water and food supply, and habitat availability will all be affected by climate change. Grassland and plains birds, already stressed by habitat fragmentation, could experience significant shifts and reductions in their ranges.
Shifts in the region’s population from rural areas to urban centers will interact with a changing climate. As young adults move out of rural communities, small towns are increasingly populated by a vulnerable demographic of the very old and the very young, placing them more at risk for health issues that are projected to increase with climate change. The Great Plains region is home to 65 Native American tribes; the people on tribal lands face additional challenges, in part because the fixed borders of reservations limit their ability to respond to climate change. Many reservations already face severe problems with water quality and quantity, and these problems are likely to be exacerbated by climate change.
Adapted by Melanie Lenart, University of Arizona
Other Regional Climate Change Impacts from USGCRP: