Quote:
Originally Posted by guihong
I am a geologist by major. My thoughts:
"Global warming" can either mean the natural warming of the planet or the hypothesis that man is destroying the atmosphere and warming the planet by our own actions.
Earth has always had climate change, either cooler or warmer, most obviously in the Ice Ages. The Mesozoic era, when the dinosaurs dominated, was actually warmer than we are now.
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The only problem I have with this is that yes, the Mesozoic was warmer but the species that were alive then but are no longer alive now were adapted to *that* climate. When the climate changed drastically and rapidly, most likely due to an asteroid strike, whole phyla were wiped out because they didn't have time to adapt. As you are aware, a change in climate happening over, say, 200K, 300K, 500K, years is one thing (that's a lot of generations for some animals) is one thing. That same change happening over a period of 100 or 200 or 300 years is not a lot of time at all. Sure, that's a lot of *mouse* generations but it's only 15 generations--at most--for, say, elephants or whales or, for that matter, us.
My concern isn't with the rise in temperature in absolute terms--provided we don't see serious spikes outside of the normal range that shouldn't be a problem. Rather, my concern is with the combination of the rapidity of change and the degree of change. Six or seven degrees C within a century is a big shift and one that I'm not sure how many species that live in temperate or arctic climes could handle that sort of shift long term.
I know that species extinction happens. I know that *mass* species extinction happens. But once we become aware that *we* are causing mass extinctions, I think both prudence and ethics dictate that we at least consider doing something to ameliorate the situation. We can't stop big rocks from hitting the planet (well, maybe we could) but we can stop ourselves from heating the planet so much that we get into a really bad feedback loop and then, a few thousand years from now, some intelligent species, following a faint radio broadcast that could *only* have come from an intelligent species, parks its ship in low-earth orbit and finds that Sol has two very hot, rocky planets with runaway greenhouse effects instead of the one it currently has.
Cheers
Aj