Friday, July 17, 2009

Ace o’Science

by Tintin
"Now which way is north?"

Watching some of the high-traffic wingnuts "do" science is a guilty pleasure, particularly when "done" by folks like Ace o'Play-doh and Don Bob Surber, both of whose scientific backgrounds appear to have been mostly garnered from careful study of NCIS reruns. Usually, their pseudo-scientific expertise on climate change is applied to a news report that it snowed in Las Vegas, or a rare southern sighting of the abominable snowman in a shopping mall in Mobile, or melting polar icecaps on Mars where there are no SUVs. ("Explain that, libs!")

The latest bauble to catch the eye of Ace and Don Bob has the tantalizing title "Global Warming: Scientists' Best Predictions May Be Wrong." With undisguised glee, Ace quotes the opening paragraph of the Science Daily article he links:

No one knows exactly how much Earth's climate will warm due to carbon emissions, but a new study suggests scientists' best predictions about global warming might be incorrect.

This is, of course, an occassion for Ye Olde Ace to stop playing World of Warcraft long enough to watusi around his garden-level efficiency and decide to order in a Papa John's "The Meats" Pie for a celebratory mid-day snack. Hell, this would be reason for Ace o'Play-Doh to go buy a big honking H3 and live in it with the engine running 24/7, right?

Sadly, no!™

Here's an abstract of the study in question, and it pretty much confirms what the Science Daily article and this article said it said. The Palaeocene-Eocene Thermal Maximum was a period around 55 million years ago when global temperatures increased 5–9 °C within a few thousand years. What the scientists did was study sediment cores in seabeds around the world to estimate the amount of carbon released prior to the PETM, and they found that carbon dioxide levels increased 70% prior to the PETM.

Now, here's the money quote from the abstract:

At accepted values for the climate sensitivity to a doubling of the atmospheric CO2 concentration, this rise in CO2 can explain only between 1 and 3.5 °C of the warming inferred from proxy records. We conclude that in addition to direct CO2 forcing, other processes and/or feedbacks that are hitherto unknown must have caused a substantial portion of the warming during the Palaeocene–Eocene Thermal Maximum.

Translated into simple English (in the event that Ace or Don Bob Surber are moving their lips and scratching their foreheads while reading this post), the study doesn't say that carbon dioxide doesn't cause global warming. In fact, the study relied on "accepted" values for the correlation between atmospheric carbon dioxide levels and global warming. The entire point of the study was that smaller increases might result in more global warming than predicted, particularly if there is a "feedback" process involved. In other words, it's not a question of whether the planet is fucked, it's a question of whether it may be fucked worse than we thought.

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