There is a report of a study on the effect of wind turbines on climate. The article on April 15 2010 by “skyler hype” is
Excerpts from the text read
“Ron Prinn, TEPCO Professor of Atmospheric Science, and principal research scientist Chien Wang of the Department of Earth, Atmospheric and Planetary Sciences [of the Massachusetts Institute of Technology], used a climate model to analyze the effects of millions of wind turbines that would need to be installed across vast stretches of land and ocean to generate wind power on a global scale….In a paper published online Feb. 22 in Atmospheric Chemistry and Physics, Wang and Prinn suggest that using wind turbines to meet 10 percent of global energy demand in 2100 could cause temperatures to rise by one degree Celsius in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions. Their analysis indicates the opposite result for wind turbines installed in water: a drop in temperatures by one degree Celsius over those regions.”
“Using a climate model developed by the U.S. National Center for Atmospheric Research, the researchers simulated the aerodynamic effects of large-scale wind farms — located both on land and on the ocean — to analyze how the atmosphere, ocean and land would respond over a 60-year span. For the land analysis, they simulated the effects of wind farms by using data about how objects similar to turbines, such as undulating hills and clumps of trees, affect surface “roughness,” or friction that can disturb wind flow.”
There is, however, a fundamental flaw in their study. Turbines do not influence the atmospheric boundary layer in the same manner as forests and hills, as these impediments cover a much larger fraction of the surface area. Indeed, wind turbines are more like individual trees that are separated by a distance. In this case, wind that is impeded by the tree just flows around it without much of an area average reduction in speed. There would be little effect on the climate from the wind turbines except in their immediate vicinity, where they would affect the vertical mixing near the surface (similar to what wind machines do for frost/freeze protection in citrus and other crops) but would not significantly alter the fluxes of heat, moisture and winds higher in the atmosphere on larger spatial scales.
Indeed the authors seem to recognize the limitation of their study (at least for the oceans) where the reporter writes
They said that these results are unreliable, however, because in their analysis, they modeled the effects of wind turbines by introducing surface friction in the form of large artificial waves. But they acknowledge that this is not an accurate comparison, meaning that a better way of simulating marine-based wind turbines must be developed before reliable conclusions can be made.
While there are environmental issues with turbines, such as the risk to birds, but large-scale climate change is not one of them.