Monday, January 19, 2009

More nonsense from the skeptics

I regularly receive angry e-mails from people who believe global warming is just a big hoax. These folks always have a new piece of misinformation to share.

The latest barrage of messages to fill my inbox point to an article by Michael Asher of, a publication, as one blogger put it, "more focused on iPhones than atmospheric science." Nonetheless, many have accepted Asher's latest story as a legitimate criticism of the theory of man-made climate change. I'll briefly explain why it's not.

Michael Asher is a favorite of the climate skeptic crowd. Late last year, as some may recall, he wrote a widely circulated article claiming ice extent in the Arctic had grown "twice the size of Germany" since 2007. The story received quite a bit of attention, as it appeared to debunk the commonly held belief that Arctic ice is melting away.

In reality though, Asher's article was dead wrong. Instead of using data from September, when the ice reaches its annual low, Asher foolishly used measurements from August, before the melting was complete.
The correct and relevant data would have shown Arctic sea ice continuing its downward trend, surpassed only by the previous year.

Despite Asher's poor research, his misleading argument was picked up and repeated by several popular websites.

Now he has done it again. In his latest piece, Asher says levels of global sea ice are equal to those observed in 1979, implying global warming predictions are incorrect. Of course, he has no clue what he is talking about, as most of the near-term climate predictions focus on regional ice losses, not global. Asher is trying to debunk something he clearly does not understand.

He cites data from the Arctic Climate Research Center at the University of Illinois. Check out their website. They have a ton of useful information, but none of it contradicts the scientific consensus on global warming. In fact, after being bombarded with e-mails about Michael Asher's article, they issued a statement to clarify the issue.

"In the context of climate change," they write, "GLOBAL sea ice area may not be the most relevant indicator." This is an amazingly polite way of saying Asher uses the wrong data.

Climate change models project sea ice area losses in the Northern Hemisphere, but the Southern Hemisphere is a different story. This, again, comes directly from the research center Asher cites in his article:
"Almost all global climate models project a decrease in the Northern Hemisphere sea ice area over the next several decades under increasing greenhouse gas scenarios. But, the same model responses of the Southern Hemisphere sea ice are less certain. In fact, there have been some recent studies suggesting the amount of sea ice in the Southern Hemisphere may initially increase as a response to atmospheric warming through increased evaporation and subsequent snowfall onto the sea ice. ... N. Hemisphere sea ice area is almost one million sq. km below values seen in late 1979 and S. Hemisphere sea ice area is about 0.5 million sq. km above that seen in late 1979, partly offsetting the N. Hemisphere reduction."
In other words, Asher's entire article is based on a false assumption. If he had simply paid attention to the climate models he was critiquing, he would have discovered those wacky climate scientists were spot on.

This past summer, Arctic ice extent reached is second lowest level in recorded history. Perhaps more importantly, the older, thicker perennial ice nose-dived, meaning the total volume of ice appears to have hit an all time low. Scientists now predict the Arctic will be ice-free in the summer time within a few years.

As the Arctic Climate Research Center at the University of Illinois summarized:
"Global climate model projections suggest that the most signi´Čücant response of the cryosphere to increasing atmospheric greenhouse gas concentrations will be seen in Northern Hemisphere summer sea ice extent. Recent decreases of N. Hemisphere summer sea ice extent (green line at right) are consistent with such projections."
Listen to the experts, not the idiots.

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