Sunday, June 15, 2008

Why aren't we dead already?

There's an interesting article in the Nation magazine this week on global warming. Note I said interesting, not coherent. The author, Mark Hertsgaard, makes the following curious statement:

The concentration of carbon dioxide in the earth's atmosphere in 2007 was 385 parts per million and climbing 2 ppm a year. Alarmingly, Hansen's study concluded that 350 ppm is the maximum level compatible with a livable planet. In other words, humanity is already in the danger zone and must reverse course rapidly.
(He is referring to James Hansen, a scientist very vocal on the dangers of global warming).

Hertsgaard wants the reader to think: "We're past the breaking point- the end is near if we don't massively cut CO2." But it seems like the article avoids a key question: If we're well past 350 ppm already, and we're not in an unlivable planet, doesn't that indicate that Hansen is being an alarmist? If we are OK on 385 ppm, why is 350 ppm the breaking point? Is it remotely possible that the link between CO2 and temperature is overstated? Just asking...

In a completely unrelated note, Hertsgaard has written the best book I ever read on the Reagan presidency, On Bended Knee.

One article on global warming I highly recommend is Alexander Cockburn's Dissidents Against Dogma. He is a leftist skeptical of the anthropogenic global warming theory, which is hard to find.


Jamie Henn said...

I think your analysis of the 350 ppm target misses the point. Hansen isn't saying that anything above 350=death, he's saying that we're in the danger zone when it comes to climate.

A more appropriate metaphor than kicking the bucket, is cholesterol. Try this one from an editorial on 350 by Bill McKibben in the L.A. Times:

"So it's a tough diagnosis. It's like the doctor telling you that your cholesterol is way too high and, if you don't bring it down right away, you're going to have a stroke. So you take the pill, you swear off the cheese, and, if you're lucky, you get back into the safety zone before the coronary. It's like watching the tachometer edge into the red zone and knowing that you need to take your foot off the gas before you hear that clunk up front."

350 is a tough target, no doubt about it. But it's what we need to do - not just for ourselves (you're right, we're not going to be the ones feeling the worst impacts of climate change), but for the majority of the world's population that is more vulnerable to the effects of climate change.

Anonymous said...

One thing that you overlook is that the present average temperature are not in equilibrium with present CO2 levels: the is a lag.

See page 5 of Hansen, et al. Target Atmospheric CO: Where Should Humanity Aim?

Jack Davis said...

Thank you for your thoughtful response. I cannot, by the way, access your profile. I would like to see your blog.

My question: How do we know Hansen's number of 350 is really the danger zone? Maybe he was overly pessimistic and the real number is 425 or 450. I suspect nobody really knows where the danger zone is. Does Hansen actually know that the number 350 is significant or is it just arbitrary?

Jack D.