Come a little bit closer

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Estimates of when the Arctic will be substantially ice free in summer used to be out towards the end of this century. In 2007, the IPCC’s fourth report suggested that there would still be a fair amount of summer ice in the 2080-90s, but the record minima of recent summers have been forcing a rapid review of that expectation. We’ve had “rough” estimates of perhaps the 2030s, and even a suggestion it could happen as early as 2013 (follow the sea ice tag for earlier posts). A new paper by Wang and Overland in this week’s Geophysical Research Letters takes a more quantitative approach, by using six models and priming them with the sea ice state after the dramatic melt seasons of 2007 and 2008 (NOAA press release):

The area covered by summer sea ice is expected to decline from its current 4.6 million square kilometers (about 2.8 million square miles) to about 1 million square kilometers (about 620,000 square miles) – a loss approximately four-fifths the size of the continental U.S. Much of the sea ice would remain in the area north of Canada and Greenland and decrease between Alaska and Russia in the Pacific Arctic.

You can see the ice distribution in the small image at the top of the post (click on it for the larger original). The paper’s abstract tells us when this might happen:

Using the observed 2007/2008 September sea ice extents as a starting point, we predict an expected value for a nearly sea ice free Arctic in September by the year 2037. The first quartile of the distribution for the timing of September sea ice loss will be reached by 2028.

I interpret that to mean that the central expectation is 30 years, but some models suggest it could be a decade earlier. I wonder what effect that might have on the permafrost and methane hydrates… AP coverage here. Meanwhile, the NSIDC has declared this winter’s maximum extent was reached on February 28th, at 15.14 million km2 — the fifth lowest winter maximum in the record. They note:

The six lowest maximum extents since 1979 have all occurred in the last six years (2004 to 2009).

The betting season is now open. I’m on double or quits with Stoat (aka wmconnolley when he shows up here), but as he’s offering 2-1 to newcomers, I might be back to evens. I think I’m also betting with malcolm (Vibenna) again… I won’t offer any sort of form guide until later in the season, but (as ever) I’m hoping to lose, but at least half expecting not to.

[Jay & The Americans]

Let it blow

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Couldn’t resist this on a Friday: more pictures of Katey Walter, the University of Fairbanks, Alaska ecologist who studies methane bubbling out of lakes in Alaska and Siberia. I think the clip’s from the BBC series Climate Wars, presented by Iain Stewart, but I couldn’t swear to it…

[Richard Thompson, with NZ lyric: warning, intimate kiwifruit/banana interface]

The inner mounting flame

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The rapid climate change underway in the Arctic has the potential to disrupt weather patterns around the planet, and brings with it the risk that methane bubbling out of the permafrost that rings the Arctic Ocean and from gas hydrates under the sea floor could make our attempts to restrain emissions and stabilise atmospheric greenhouse gases completely irrelevant. These concerns will not be news to Hot Topic regulars (try the methane and Arctic tags for earlier posts and background), but a thorough overview by Fred Pearce in last week’s New Scientist (Arctic meltdown is a threat to all humanity) pulls all the threads together and presents them in a compelling fashion. Pearce begins by looking at the experiences of Katey Walter:

“I am shocked, truly shocked,” says Katey Walter, an ecologist at the University of Alaska in Fairbanks. “I was in Siberia a few weeks ago, and I am now just back in from the field in Alaska. The permafrost is melting fast all over the Arctic, lakes are forming everywhere and methane is bubbling up out of them.”

Back in 2006, in a paper in Nature, Walter warned that as the permafrost in Siberia melted, growing methane emissions could accelerate climate change. But even she was not expecting such a rapid change. “Lakes in Siberia are five times bigger than when I measured them in 2006. It’s unprecedented. This is a global event now, and the inertia for more permafrost melt is increasing.”

Not good news.

Continue reading “The inner mounting flame”

Friedman continues to represent the science.

Thomas Friedman, the author of Hot, Flat and Crowded reviewed here on Hot Topic, continues in his New York Times column to accurately reflect what climate scientists are saying .  Saturday’s column is a fine example. As Gareth did in his recent article in the Press Friedman starts by pointing out that “climate change is happening faster and will bring bigger changes quicker than we anticipated just a few years ago.”  

He quotes Christopher Field, director of the Carnegie Institution’s Department of Global Ecology at Stanford University: ‘We are basically looking now at a future climate that’s beyond anything we’ve considered seriously in climate model simulations.’

Continue reading “Friedman continues to represent the science.”

We can run, but we can’t hide…

earthhour.jpg This article appeared in the Perspectives section of The Press yesterday, as part of the paper’s build up up to Earth Hour this weekend. I haven’t seen the letters page today, but I expect the usual suspects will be out in force… 😉

The news isn’t good. Since the Intergovernmental Panel on Climate Change (IPCC) advised two years ago that the evidence for global warming was unequivocal, the pace of change has speeded up. Summer sea ice in the Arctic Ocean has seen a dramatic decline, and in a worrying foretaste of what may be to come, methane — a much more powerful greenhouse gas than carbon dioxide — has been found bubbling out of the ocean floor off Siberia. Down south, analysis of a core drilled into the seabed under the Ross Ice Shelf by a team including scientists from New Zealand (using Kiwi drilling expertise), demonstrates that the West Antarctic Ice Sheet is unstable and likely to collapse if warming continues as we expect over the coming century. Experts are revising their projections of sea level rise upwards with each piece of bad news. A metre or more by the 2090s is now a real possibility.

Continue reading “We can run, but we can’t hide…”