This is a no-brainer to me.
Why isn't it to others?
Why has it beocme a politcal issue?
It's a scientific issue!
The question is not "if" the quesiton is "when"
We cannot continue to increasingly blow shit into our atmoshpere as our population increases and not have anything happen.
There are many reasons to cut emissions the reduction of CO2 is just one of them. I think health effects from smog and respiratory illness from smelting and coal burning are real issues that are far more serious in the near term and are very much a local problem.
As for CO2, it is a global problem and it needs to be addressed as such. Reduction of greenhouse gases in Europe or America would be easy if we shipped of our complete economy to Asia, where global warming isn't a concern. This is what Kyoto encourages.
The earth is in a natural warming cycle, this was professed by none other than National Geographic. Their concern was that human impact would make the problem worse. This is the part that is up for debate. As for global cataclysmic events happening, don't hold your breath. The science of exact how much impact people are having is in its infancy and will need quite a bit more study before any definitive answer is known. It is true that CO2 levels are there highest in over 100,000 years, but our oceans are not very much higher then they were 10 or even 100 years ago.