The thermal pollution works actually 2 ways, there is a good side. In Fort Myers (Fla) the manatees swim upriver, and hang out all winter next to the powerplant, as the water the power plant dumps back into the river is termically polluted (means warmer). They are very sensible to the temperarures, specially cold temperatures, and die if the temps get lower than a certain degree. Of course the wost enemy they have are props (from the boats)... So, thanks to the pollution, they survive a lot better the mid winters of south Florida. Washington DC, on the other hand is a exceptional place. One would guess that with all that hot air they would have their own microcimate, but no, it gets cold 'n winter anyway, it even snows...