Replying to both Pyg and MKIced,

The problem isn't that it's increasing, or even that it's increasing quickly necessarily.

The difference this time is that there is no other explanation for the quick increase, outside of humans. And the evidene of our hand in global warming is unanimous among all scientists not directly connected to some energy giant. The debate is over, but if you google global warming, you get site after site questioning the science, because Exxon, Mobil, big electric etc. put tons of effort into keeping this debate alive. The first three or four pages are almost exclusively pieces by "scientists" connected to these groups.

Now, whether overall tempurature and CO2 levels rise because of humans or nature doesn't really make that much of a difference as far as nature is concerned,

But with humans, there's no foreseeable end to the increase without human intervention. While natural reasons for warming and cooling correct themselves.

At the current rate, within 10 thousand years there will not be any more ice on the poles. While that seems like a long time, that is extremely fast on a planetary scale. If our own contribution to global warming were to be coupled by any natural cause of global warming, that would move up the clock significantly. link

Life can adopt to changes in tempurature (with little collateral damage if it's done slowly) but done quickly life cannot adopt, unless it has air conditioners and shelter. Which most of it does not.

Honestly I'm not overly concerned with every living creature on earth. I'm not really a tree hugger, though I do think polar bears are cool.

But at some point it affects people as well, negatively. And while for the most part nature replaces one species with another when something dies off.

Evolution cannot keep up with mass extinctions over short periods of time.

Yes, mass extinction has happened in the past, and we have the last one to thank for our own eventual rise to dominance. But now that we're here, I think it's in our best interest to ensure no more mass extinctions.

I realize this may cost companies like Exxon (who just reported record profits... again, in spite of a world depression) some money in the long run, but that's just a price we may have to pay...