We can tangle on details of the science, but it's more important to step back and consider the risks.
See this excerpt from Elisabeth Kolbert's interview with Bill McKibben. Is it worth an extra 2 or 3% of income, to make a high-risk gamble with the only home we've got, when it's irreplaceable?
Keep in mind that uncertainty actually makes the risk picture worse.
McKibben will speak here in Nevada City next Tuesday eve (tickets at Briarpatch), and a climate speaker from the Carnegie Institution at Stanford will speak at the May 18 Sierra Club meeting.
p.s. for newbies: SkepticalScience.com is the best resource I know of for checking out the science bearing on contrarian climate claims.