Climate change is visible and occurring throughout the U.S., but the choices we make now will determine the severity of its impacts in the future, according to a Texas Tech University climate scientist who served as a lead author on a report released by the White House.
Katharine Hayhoe, a research associate professor in the Department of Geosciences, was one of 31 scientists from 13 U.S. government science agencies, major universities and research institutes that produced the study. In 2007, she was invited to serve as the lead author for the Great Plains chapter of the report, which includes Texas.
“During the next decade or two, we are likely to see an increase of 2 to 3 degrees Fahrenheit across the United States,” Hayhoe said. “How much temperatures rise after that depends primarily on our emissions of heat-trapping gases during the next few decades. Under lower emissions, temperatures could increase 4 to 7.5 degrees. With higher emissions, we can expect 7 to 11 degrees, with the greatest increases in summer.”
Using projections such as these, authors crafted what they call the most comprehensive, plain-language report to date on national climate change. Global Climate Change Impacts in the United States provides the most current information on how climate change is likely to impact key economic sectors and regions of the country. The report spans both the Bush and Obama Administrations.
The study found that Americans already are being affected by climate change through extreme weather, drought and wildfire and details how the nation’s transportation, agriculture, health, water and energy sectors will be affected in the future. The study also found that the current trend in the emission of greenhouse gas pollution is significantly above the worst-case scenario examined in this report.
Hayhoe said heat waves, drought and heavy rainfall events are all expected to become more frequent for much of the nation, including in the Great Plains. Warmer temperatures increase evaporation. Combined with increased risk of drought, this raises concerns about the region’s water supply, already overtaxed in many parts of the Great Plains.
“Water is gold – here in Texas and across the Great Plains,” she said. “Much of it comes from the Ogallala Aquifer, which extends from Nebraska all the way down to West Texas. But on the South Plains, we’re already taking the water out faster than it can replenish, and aquifer levels across the region have dropped by more than 150 feet since irrigation began in the 1950s. Farming and ranching are already under pressure from expanding human development and limited water supply. Climate change will exacerbate these and other existing stresses on our natural environment and our society.”
Rising temperatures likely will further stress farms and ranches, shifting the areas where certain crops are grown, and allowing pests currently confined to the southern parts of the region to expand northward. Rising temperatures also will add to the pressure on the regions grasslands and playa lakes – unique habitats the Great Plains region offers to migrating and local birds as well as other wildlife.
The report emphasizes that the choices we make now will determine the severity of climate change impacts in the future. Earlier reductions in emissions will have a greater effect in reducing climate change than comparable reductions made later.
Main findings for the United States include:
• Heat waves will become more frequent and intense, increasing threats to human health and quality of life. Extreme heat also will affect transportation and energy systems, and crop and livestock production.
• Increased heavy downpours will lead to more flooding, waterborne diseases, negative effects on agriculture, and disruptions to energy, water and transportation systems.
• Reduced summer runoff and increasing water demands will create greater competition for water supplies in some regions, especially in the West.
• Rising water temperatures and ocean acidification threaten coral reefs and the rich ecosystems they support.
• Insect infestations and wildfires already are increasing and are projected to increase further in a warming climate.
• Local sea-level rise of more than three feet on top of storm surges will increasingly threaten homes and other coastal infrastructure. Coastal flooding will become more frequent and severe, and coastal land will be lost to the rising seas.
Hayhoe has led climate impact assessments for California, the Northeast, Chicago, and also contributed to the United Nations Intergovernmental Panel on Climate Change.
A product of the interagency U.S. Global Change Research Program and led by National Oceanic and Atmospheric Administration, the definitive 190-page report is intended to better inform members of the public and policymakers. It is available at www.globalchange.gov/usimpacts.