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WASHINGTON (AP) – Ramping up wind power in America would be a new study out of Harvard found.
While wind energy is widely accepted, the researchers concluded that a dramatic, all-out expansions in the number of turbines could warm the earth even more than climate change from burning coal and other fossil fuels, because of the way the spinning blades disturb the layers of warm and cold air in the atmosphere.
Some parts of the central United States are already in the process of being warmed up, said study lead author Lee Miller, an environmental scientist at Harvard.
"Any big energy system has an environmental impact," said Harvard engineering and physics professor David Keith, a study co-author. "There is no free lunch." You'll wind on a big big scale … it'll change things. "
The researchers and other scientists are more likely to be involved in climate change than in the past.
Despite the potential drawbacks, Keith said.
It's just that the advocates of wind power have been ignoring growing evidence of a downside, he said.
Overall, the Harvard study, published Thursday in the Joule newspaper, found that in the US, it was likely that it would be switched over to almost all of its electricity sources. 0.4 degrees (0.2 Celsius). Some local areas would have been localized warming around 2.5 degrees (1.4 Celsius), though there would also be some cooling in places, such as the East Coast.
Right now, wind provides 6.3 percent of the nation's electricity, according to the American Wind Energy Association.
The study, which looked at just the United States, said the turbines would be more warming in the world than the carbon dioxide.
The reason for this effect: Normally the air is more still at night, with cold air staying near the surface and warmer air resting a little higher. But turbines bring the warm air down and cool air up, making the ground a toasttier bit. The effect is seen less during the day but is still there.
Still, the effect of turbines is different from human-caused climate change. It consists of warming, it's local, and it's temporary. When the turbines are still there, there's no warming.
Climate change, in contrast, is a global effect that involves many more elements than temperature, such as sea level rise, extreme weather, melting glaciers and jet stream shifts. Even if a country stopped emitting greenhouse gases, it would still be possible to change the world.
Past studies have had a temporary nighttime warming of 2 degrees (1.1 Celsius) in places with wind turbines, such as North Texas. The Harvard study took observations and used computer simulation to project what a dramatic increase in turbines would look like for temperatures.
Other technologies considered environmentally friendly with their downsides, too. Nuclear energy has no carbon dioxide emissions, but there are concerns about waste, safety and cost. The ethanol boom has wiped out habitats, led farmers to plow over meadows, caused water pollution and raised food prices.
Wind advocates emphasized that the Harvard study does not show turbines causing global warming, just local heating.
"Michael Goggin, vice president of Grid Strategies and a researcher for a wind energy group, said:" If the paper is looking at the global and long-lasting timescales , said in a statement.
Ken Caldeira, a climate scientist at the Carnegie Institution for Science who was not part of the research, said the study is sound.
"The climate effect of burning fossil fuels is cumulative," Caldeira said in an email. "In the wind, the climate effect of wind turbines is what you are." In the long run, wind turbines are obviously better than fossil fuels. "
Follow Seth Borenstein on Twitter: @borenbears . His work can be found here.
The Associated Press Health & Science Department receives support from the Howard Hughes Medical Institute's Department of Science Education. The AP is solely responsible for all content.
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