Global warming is rapidly kicking in, changing the entire face of the Earth. Global warming has occurred in the past, for example at the end of the most recent ice age--and the ice ages before that. But this time is different. Previous global warmings have occurred slowly enough that plants and animals could migrate to new locations with the climate conditions to which they were adapted. And, to a certain extent, evolution by natural selection could allow them to adjust. However, today, global warming is occurring too fast for either of these processes to make much difference. In addition, today, farms and roads and cities block potential migratory routes.
The processes by which organisms adapted to global warming thousands or millions of years ago will not work today. This is one reason why it is so important to bring carbon emissions under control. Investment in solar and wind energy is part of the economic stimulus package that the Obama administration is pushing. This will create jobs, as well as reducing carbon emissions (and reducing our dependence on Middle East politics). Even if there were not an economic crisis right now, it would be an urgent thing to do.
Investing in renewable energy certainly makes more sense than what we did last year, when we gave billions of dollars to banks to use as they pleased, and they used some of it to pay millions of dollars to their executives who got us in the economic crisis in the first place. Investing in bank executives is like putting money down various kinds of holes; but investing in "green energy" will pay big returns--some of them now, and even more over the long run.