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Texas wind farms' impact on climate causes stir

By Wendy Koch, USA TODAY

A small scientific study linking Texas wind farms to higher surface temperatures has led to dramatic media headlines about wind farms causing climate change. Yet its lead author doesn't say that nor does earlier research.

The study, published online this week in the journal Nature Climate Change, used satellite data to analyze land surface temperatures near a few large wind farms in Texas from 2003 through 2011. It found a nighttime warming effect over the farms of up to 0.72 degrees Celsius per decade. It says the turbines act like fans to pull down warmer air from the atmosphere closer to the ground.

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"The warming effect reported in this study is local and is small compared to the strong background year-to-year land surface temperature changes," Liming Zhou, an atmospheric scientist at the State University of New York- Albany who led the research, wrote in an accompanying Q&A about his paper. He added:


Anjuli Bamzai of theNational Science Foundation, which funded the research, noted that the findings are "for a relatively short period" but said they raise "important issues that deserve attention as we move toward an era of rapid growth in wind farms in our quest for alternate energy sources."

Indeed, they do raise relevant questions. This study and earlier research, however, do not find a causation between today's wind farms and climate change.

"We find that very large amounts of wind power can produce non-negligible climatic change at continental scales. Although large-scale effects are observed, wind power has a negligible effect on global-mean surface temperature, and it would deliver enormous global benefits by reducing emissions of CO2 and air pollutants," reports a 2004 study led by David Keith of the University of Calgary.

That study's finding, published in the Proceedings of the National Academiesof Science, was based on wind generating two terawatts of electricity worldwide -- about 10 times what was generated last year.

"Wind-induced turbulence does produce vertical mixing in the atmospheric boundary layer that increases nighttime surface temperatures," writes Samir Succar of the Natural Resources Defense Council, an environmental group. He says:

This is a small, local impact that should not be confused with what is typically thought of as "climate change." One possible outcome of this local effect is that you would be able to extend growing seasons for crops grown near wind turbines. There might be additional impacts that haven't yet been anticipated, but it is clear that these impacts bear no resemblance in scope, magnitude or severity to global climate disruption.

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