Who said the butterfly effect couldn't apply to renewable energy? Though wind farms are considered pretty green on the energy-generating spectrum, it looks like they, too, have an impact on the planet. According to a study published today in the journal Nature Climate Change, turbines can raise the local temperature -- albeit slightly. From 2003 to 2011, researchers monitored satellite data for west-central Texas, which is home to 2,350-plus turbines and four of the world's largest wind farms. In that decade, scientists observed a temperature increase of 0.72 degrees in wind farm regions compared to areas without turbines. That warming trend was especially marked at night, when the temperature difference between the ground and the air is highest. The temperature increase was also higher in winter; researchers say that these cooler, windier conditions cause turbines to generate more electricity and therefore create more heat. Since the study didn't find any change in daytime temperatures, it looks like we don't have to ring the global warming alarm just yet.