Arctic sea ice will be below average again this year

Bad Astronomy
The entire universe in blog form
Aug. 30 2011 6:30 AM

Arctic sea ice will be below average again this year

Geez, I hate to keep hitting this theme, but y'know what? It's important.

Using a fleet of Earth-observing satellites, the European Space Agency is reporting that the ice in the Arctic circle is already retreating considerably, and will once again be below average in extent this summer. This has been going on for a few years now, which isn't terribly surprising considering that global warming is real and that we keep seeing recent years tied or exceeding records as hottest years on record.

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Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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Here's the map they made showing sea ice extent from June 1 to August 24, 2011:

Yikes. Back in 2007, the Northwest Passage became entirely navigable by sea (without using an icebreaker ship) for the first time in recorded history. It had already been thinning for years, but an icebreaker ship was still needed to get through all of it -- that's changed now.

Moreover, it's not just that the extent -- that is, the amount of area covered by the ice -- has dropped, it's also that it's thinning, dropping in volume. The ice volume has decreased by unprecedented amounts as well recently.

What does this mean for the current Arctic summer?

"The minimum ice extent is still three to four weeks away, and a lot depends on the weather conditions over the Arctic during those weeks," says Leif Toudal Pedersen, a senior scientist at the Danish Meteorological Institute. "Whether we reach an absolute minimum or not, this year again confirms that we are in a new regime with substantially less summer ice than before. The last five summers are the five minimum ice extent summers on record."

[Emphasis mine.]

Just to be clear: it's OK to question the science of global warming. It's OK to question any scientific findings, as long as that questioning is done with good intentions and in good faith (so to speak). While poking around the web I found denier sites trying to confuse the issue of sea ice extent -- for example, some talking about the navigability of the Northwest Passage as far back as 2000, but not mentioning you needed an icebreaker to do it.

As usual, the evidence here is pretty clear: temperatures are increasing, sea ice is going away, glaciers are retreating, ocean levels are rising, and all the while we're dumping greenhouse gases into the atmosphere while the spin doctors whirl away.

It's maddening. But it will continue, as surely as the Earth itself turns.



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