What people tend to overlook in this debate is that we can actually look back to a time when all this
CO2 was floating about in the atmosphere. Yes, in the distant past, around the time that
dinosaurs were roaming the
continents, most of that
CO2 had not been deposited underground yet and was still found in the atmosphere. And, although changes in
solar radiation and earth
orbit also affect climate, we can presume that if all the
carbon dioxide reenters the atmosphere, the climate will become more like it was then.
Well, what was it like back then? Was it a 'good' climate? It depends on your viewpoint. The climate was much warmer, and wetter. Vast swamps, rainforests, and shallow seas covered the land. Grasslands were unknown, because grass hadn't evolved yet, but even if it had, there would not be appropriate conditions for it to thrive. If you were a dinosaur, a fish, or a mosquito, you would be quite content with this climate. Indeed, for animals as a whole, and plants as a whole, this type of climate would be very rich and productive.
But what about us? Humans evolved during consecutive ice ages, to survive blistering cold, and hunt animals on the savannahs and grasslands. Later, we also took up agriculture in these areas. Ever try to farm a swamp? To some extent, rice and other crops can be grown in swamps. But it certainly wouldnt be a fun existance. And what of the shallow seas which would cover our most productive land?
Over hundreds of years, humans have been destroying swamps, rainforests, and coastal marshes. Although humans are likely to want to preserve vast tracts of mountain, desert, and rangeland, until recently no one lamented the loss of wet areas. Why is this? Well, its because we don't do well in these areas. Humans just arent meant to live there. And wouldnt it be amazingly ironic if we were destroyed by the very rainforests, swamps, and marshes that we once almost eliminated?
Do we need more research on this? Hell yes... do we need to make sure our actions are based on scientific research? Again, yes. But as this strikes deep at the roots of the values of Western society, it is virtually impossible to be impartial when we look at this; holding an impartial attitude will be our biggest challenge.