Here's a totally different way to think about global warming.
If anthropocentric (human-caused) global warming is just environmentalist hysteria, then we've got another 10-50 years (100 years if you're particularly optimistic) of inexpensive oil sitting under the ground, and nothing worthwile to stop us from using it, so long as the pollution it produces is limited to just CO2, which has no health-related side effects. We'll need another energy source eventually, since no matter how optimistic you are you know fossil fuels are finite, but hey, that's a long time from now.
If global warming is a reality (which is debatable), and on the severe side of what scientists think might happen, then the outcomes described in that report aren't at all out of the realm of belief--the economic and humanitarian costs of major climate change, including food production shifts and unusually severe weather, would be disasterous. War and mass civil unrest aren't at all out of the ordinary.
And the truth is, it's impossible to say for certain which is the case.
What does that mean? Let's say there's just a 10% chance that global warming might actually be severe--I'm sure you can find at least 10% of the respected climatologists in the world who think so. Pretty small chance.
That means that there's a 10% chance, well within the lifetime of most people, of mass-scale disasters, famine, war, and the possible collapse of first world civilization as we've come to know it if we keep doing things the way we are, and a 90% chance everything's ok unless some terrorists loose a biological weapon or something.
Is it really worth that 10% risk to keep up business as usual, espeically when you consider that the supply of fossil fuels will run out eventually anyway?
I know if you told me that driving my car would give me a 10% chance of developing cancer in the next 30 years I'd find another way to get around, just in case.
And personally, based on a whole lot of real science, I'd say the chance is a lot higher than 10%. So is it really worth the risk, even if it might just be paranoia? I'd rather just be on the safe side.