there's a study recently that associates local surface warming with windmills. that's an interesting result. and i can't wait for further research to come along and explain it. until then we can't realistically draw any conclusions. yes, science is boring. hype is exciting. and newsworthy. which is why you've probably already seen headlines like, windmills cause global warming. the leap from local surface warming to global warming is quite large. and while, it may be true, at this point is seriously unjustified. i can think of a few scenarios where it's just flat out wrong. first, sometimes a layer of warm air gets trapped between layers of cold air. windmills tend to mix the air downwind from them. this mixing might free the previously trapped warm air to move both up and down. the net result would be warmer surface temperatures and global cooling. second, wind speed is reduced downwind from a windmill. which may result in less evaporation of surface water. water vapor is a green house gas many times more potent than carbon dioxide. less greenhouse gas means less warming. that's just off the top of my head. i could be completely wrong. we are in the guessing stage. that's what makes it so interesting. to me if not the media consuming crowd. further study required.