Climate scientists have moved beyond whether CO2 in the atmosphere causes warming. You can read the signature of CO2 capturing radiant energy in the spectrum of the planet. I have read the IPCC AR4 Working Group I Summary for Policy Makers. What's your point? You don't like the way they're simplifying the uncertainty for non-scientists? If they can't be virtually certain about something but only consider it very likely we can ignore the risk? Science doesn't work in absolutes (except zero).
The WG1 report is all about the science and doesn't get into danger, it's Working Group II where that part comes in. That's where they examine the probable effects of global warming.
LOL!! So they're "simplifying uncertainty"? And "that's how science works"? The summary for policy makers is marketing speak, *not* science and you're either ignorant of what real science is or fooling yourself. Which is it? Which one of the values above represents "settled science"? I think the only thing that is settled is that it's going to get slightly warmer, and that prediction is seriously in doubt. When do we get to call the IPCC out on the failures of their "Climate Scenarios"? (they're not brave enough for predictions). Or is that something we'll just sweep under the rug because it doesn't empower unscrupulous scientists and crooked bureaucrats and politicians? Oh yeah Working Group II. Thanks for mentioning that. That's where they predict the Himalayan Glaciers will melt by 2030 right?
Man is the best computer we can put aboard a spacecraft ... and the only one that can be mass produced with unskilled labor. -- Wernher von Braun