05 Aug 2011:
Rising CO2 Levels Could Offset
Drying Effects of Higher Temperatures
As the world warms, rising temperatures are expected to dry out the planet’s semi-arid rangelands. But a new study by U.S. scientists suggests that the effects of that drying are likely to be offset
by the way in which plants react to elevated concentrations of CO2 in the atmosphere. Higher temperatures increase water loss to the atmosphere, but scientists from the U.S. Department of Agriculture (USDA) found that higher CO2 levels also cause leaf pores, or stomata, to partially close, which actually slows the evaporation process. The scientists are conducting an 8-year study on dry grasslands in Wyoming, and are simulating future climate conditions — when temperatures could rise by 5 degrees F and atmospheric CO2 concentrations could soar from today’s 390 parts per million to 600 ppm — by using infrared heaters and CO2 piped into experimental plots. The preliminary results of their studies, published in the journal Nature
, show that dry grasslands are likely to experience no change in soil water and that warm season grasses may actually grow more quickly under future climate conditions. Dry rangelands make up roughly one third of the Earth’s surface and USDA scientists say their research may help ranchers and farmers plant grasses and crops that are likely to fare better as temperature and CO2 levels increase.
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Tribal people and ranchers join together to stop a project that would haul coal across their Montana land. Watch the video.
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An aerial view of why Europe’s per capita carbon emissions are less than 50 percent of those in the U.S. View the photos.
The 2015 Yale e360 Video Contest winner documents a Northeastern town's bitter battle over a wind farm. Watch the video.
video series looks at the staggering amount of food wasted in the U.S. – a problem with major human and environmental costs. Watch the video.
video goes onto the front lines with Colorado firefighters confronting deadly blazes fueled by a hotter, drier climate. Watch the video.
A three-part series Tainted Harvest
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