Thursday, July 16, 2009

Our Best Guess Is Is Likely Wrong (AGW Could Be WORSE Than Expected)

Marc Morano jumps all over the press release for this paper (Carbon dioxide forcing alone insufficient to explain Palaeocene–Eocene Thermal Maximum warming), and is flogging it as yet another blow to the theory of AGW. But he's got nothin'. From the release:

Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today's climate models include accepted values for the climate's sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.

Which is to say that something else must have caused the other half of the PETM warming. Co-author Richard Zeeb explains:

But Zeebe said this [the release of CO2] could only explain a 1 to 3.5 degree Celsius rise in temperatures, adding that a commonly accepted scientific range for a doubling of CO2 is between 1.5 and 4.5 degrees Celsius.

This meant other factors must have been at work to drive up temperatures between 5 and 9 degrees Celsius.

And if there are unknown factors that contributed to the PETM warming being greater than current models predict, then it is quite possible that future warming will be greater than what current models predict, as these unknown factors add their weight to the equation:

"If this additional warming which we do not really understand, was caused as a response to the CO2 warming, then there is a chance that also a future warming could be more intense than people anticipate right now," Zeebe said.

In addition, and contra Singer, who argues on CCNET that

Their discussion simply *assumes* that CO2 should be the cause of the sudden warming 55 my ago.

...the paper, more specifically Zeebe's later discussion with Reuters, makes no such assumption, at least if "cause" = "PETM trigger event".

"There may have been an initial trigger," he told Reuters on Wednesday from Hawaii. This could be a deep ocean warming that caused a catastrophic release of methane from hydrate deposits under the seabed.

...which is one of the standard theories in the relevant PETM literature.


Ti-Guy said...

Nuh's cooling.

Beating Fred/Paul S./Hentai addict #38983 to the punch. to finish reading your post.

Ti-Guy said...

Done. Always good to remind your readers who Marc Morano is:

Morano is a former journalist with Cybercast News Service (CNS), which is owned by the conservative Media Research Center. CNS and Morano were the first source in May 2004 of the Swift Boat Veterans for Truth claims against John Kerry in the 2004 presidential election and in January 2006 of similar smears against Vietnam war veteran John Murtha.

Gerrard787 said...

With all these dire predictions I think we're now about 14 days ways from a no-turning-back 'tipping point' unless we reduce our CO2 emissions 90% by next Monday. Time for action!

Unless even worse news comes out before then.

Ti-Guy said...

Unless even worse news comes out before then.

For Paul S., that could be one things...LARP'ing has been outlawed.

word verification: "dingbuff."

Are you going to let Blogger speak to you like that, Paul?