Global warming is bullshit man, but yes, the amount of electricity used by bitcoin mining is pretty atrocious. GPU's use more electricity than even ASICS, but they have less hashing power. The problem isn't as bad if everyone migrates to Komodo platform, where all block chains are hashed by bitcoin or whatever the chain with highest hash rate is. This is the future. The other way to look at this is, if bitcoin becomes a real accepted global currency, lots of money will pour into ways of generating the power to run the hashing equipment much cheaper or free. Lot of miners are already building farms that run off geothermal etc.