well, if the power got into the wrong hands it would - but the deserts at tone time had vegetation and the arctic had tropical forests that would be kind of cool to happen again (except those places at sea level right now would be obliterated)
Well, doesn't technology always get into the wrong hands sooner or later? But a lot of vegetation and animals are dependent on climate and weather. I've heard that animals already die out if the average temperature over the year only changes by 2°C, so I'm pretty sure even changes in the weather can already have consequences.
Yeah that won't be easy. And then you'll have to make it safe enough so it can't be abused or taken over by bad people. Or the next terror attack will be: Snow storm (or alternatively: heat wave) all year for nations they don't like. xD;
Well, we're humans. There will always be people who try to abuse power for profit. And yeah, it would make for a good scifi. Actually, can't imagine that noone made a book or even movie about this already. xD