Based on a study produced at the State University of NY (SUNY) at Albany, the ground around the turbines can warm up at night. This is due to the mixing, by the turbines, of the cool night air at ground level with the warmer air above. While the effect is real, the concern is not, since this phenomenon does not introduce new heat into the planet’s atmosphere, as the carbon dioxide layer does by trapping heat that would otherwise escape into space. Rather, this small, localized effect is simply mixing heat that is already there, with cooler air below it. If you think of it as a pot of soup on a stove, the sun provides the heat, the greenhouse gases form the lid, and the action of the windmills would be like you stirring the soup, albeit with a very small spoon. Life on Earth, as we know it today, evolved at temperatures that were present before the lid was on.