[Wowbagger]

Originally Posted by Richard

But many human societies have been built around a certain type of ecosystem and are heavily dependent on that not changing too much from year to year. Food production will especially fall into this category. If the ecology of a whole region changes then the human systems that depended upon that ecology could be put under extreme stress.

Most our current environmental problems are specifically caused by the difficulty of changing strongly implemented methods of functioning. The relations and interactions between us and their our environment, is dependent not only the other living organisms, but also on our own technologies. So, variables in our environment both us and our technologies are affected, and a rearrangement need to occurs in order to maintain or conserve the same efficiency in our methods.

Between, the time the environmental change and rearrangement occurs, this is when we're put under extreme stress, as you says. This stress is relative on many factors of course, so its degree of intensity can be low as much as it can be high. Nonetheless, after the rearrangement occurs, the life can either be better, worse or the same. In the case of a global warming, where more kinetic energy is available, and where biomass increase, the chances are that life will be better. The phenomena of gigantism that happened from the late Triassic period (about 230 million years ago) to the end of the Cretaceous period (65 million years ago) was made possible by a far more tolerable climate. The co2 level was between 1750 ppm and 1700 ppm, which is 6 times more than it is now and the temperature was a few degrees higher.

In the case of a few degrees global warming, a whole desert like the Sahara could very well become a tropical rain forest. This doesn't take much to see such a change. A forest doesn't simply absorb water, it also recycle it back in the atmosphere through transpiration, instead of being lost in the earth's crust, which then fall farther inland to feed more vegetation. This chain of effect can be started by just a small temperature increase.
In a blog I read... No I'm kidding lol... In the journal Science this month there'll be an article about just what I'm talking about: Sahara dried out slowly, not abruptly: study | Environment | Reuters . "

OSLO (Reuters) - The once-green Sahara turned to desert over thousands of years rather than in an abrupt shift as previously believed, according to a study on Thursday that may help understanding of future climate changes.

And there are now signs of a tiny shift back towards greener conditions in parts of the Sahara, apparently because of global warming, said the lead author of the report about the desert's history published in the journal Science.
[...]
The Sahara got greener when temperatures rose around the end of the Ice Age about 12,000 years ago. Warmer air can absorb more moisture from the oceans and it fell as rain far inland.

"Today I think we have the same thing going on, a global warming," he said. And he said there were already greener signs in a huge area with almost no reliable weather records.

"I see a clear trend to a new greening of the Sahara, a very slow one," he said, based on visits to some of the remotest and uninhabited parts of the desert over the past two decades.