The National Snow & Ice Data Centre in the USA has declared that this year’s minimum Arctic sea ice extent has been reached – 4.52 million square kilometres on September 12th, only 390,000 km2 more than the record 2007 minimum (and 2.24 m km2 below the 1979-2000 average minimum). It looks as though their line may bump along the bottom of the graph for a while, so there may be some potential for that number to reduce a little. Their figure for Sept 12 is 9.4 percent above the 2007 minimum, so unless there’s some unprecedented melt over the next couple of weeks, I am prepared to accept that I have lost my bet with Malcolm (see comments here and at Poneke! here), which was based on NSIDC numbers. My cheque book is at the ready.
Tag: glaciers
Beat the retreat
New Zealand’s glaciers lost 2.5 km3 (2.2 billion tonnes) of permanent ice from April 2007 to March 2008, leaving 44.9 km3 of ice in the Southern Alps – the lowest amount since NIWA began regular surveys 32 years ago. The picture (credit: “Mr Ice” Trevor Chinn, click for larger image) shows the Marion Glacier in the Arawata Valley in South Westland which has recently retreated above its proglacial lake. The annual survey uses a fixed wing aircraft to record the height of the snowline at the end of summer (and Trevor gets to take the pix). Jim Salinger, NIWA’s principal scientist, says that the survey shows that the glaciers had lost a lot more ice than they had gained over the preceding winter [press release]:
“As a result of La Niña conditions over New Zealand, more easterlies, and warmer than normal temperatures, there was less snowfall in the Southern Alps and more snowmelt. The higher the snow line, the more snow is lost to feed the glacier. On average, the snow line this year was about 130 metres above where it would need to be to keep the ice mass constant.â€
More below the fold…
Like takin’ candy from a baby
Another day, another bet on sea ice. A few days ago, a regular reader of HT emailed to ask me if I could provide some support in a long series of comments to a post at Poneke! about the showing of Swindle. So I did (my contributions start here). And now I have another bet on this northern hemisphere summer’s sea ice minimum, with a commenter calling himself “malcolm” taking the Stoat position (cold side = more ice than last year, not something out of the Kama Sutra). So here’s an update on events up North. Consider it a form guide, if you will.
“The Arctic ice is back to normal.” Yeah, right.
This New Scientist video includes some rather spectacular images of a rapidly draining meltwater lake on the surface of the Greenland ice sheet. The three kilometre wide lake drained down through 1 km of ice in an hour and a half, at a rate similar to that of the water flowing over the Niagara Falls. Full story here, and more detail from NASA here. Meanwhile, RealClimate covers the factors driving the acceleration of Greenland’s outlet glaciers, the principle mechanism for getting large volumes of ice into the ocean. There’s some interesting stuff in the comments, too, particularly from a scientist (Tad Pfeiffer) working on establishing an upper limit to the contribution to global sea level rise likely from Greenland’s glaciers. Nature also has a very nice overview article on the state of research on the GIS, but unfortunately it’s hidden away behind a paywall.
Offshore in the high Canadian Arctic, Canadian Rangers have discovered large cracks are appearing in the Ward Hunt ice shelf, a large chunk of very old and thick ice on the northern coast of Ellesmere Island. The Arctic sea ice has now begun its spring melt back, and the National Snow & Ice Data Centre has posted a page to monitor this summer’s events. The time series graph of ice extent (here) compares current ice to last year’s record and the 79-2000 average. You can monitor ice area (a slightly different metric) at Cryosphere Today (here).
Down South, more results from the Andrill Project were presented at last week’s European Geophysical Union conference. Researchers now have a climate history for the continent stretching back 17 million years, and there are plans to drill a new core (starting in 2012) to take that back to 40 million years, when the continent started iceing up. Grab the Nature article before it disappears behind a paywall.
This is the Tasman Glacier, near Mt Cook, from the lookout on the lateral moraine a couple of months ago (click for a larger version: pic ©GR). New fieldwork shows that the lake is now 7 km long, 2 km wide and – amazingly – 245 m deep. The results confirm that the presence of the lake effectively dooms the glacier to disappear – within 20 years, according to the research team from Massey University. Herald story here.
Being economical with the truth, or lying through her teeth?
Politicians are skilled at manipulating facts to convey any impression they desire. It’s called spin, and in its worst cases truthiness – nicely defined by the man who invented the term, Stephen Colbert of The Colbert Report: “We’re not talking about truth, we’re talking about something that seems like truth—the truth we want to exist.” Out in wingnut land, they want to believe that global warming is not real. So Muriel Newman at her NZ Centre for Political Research web site starts spinning the facts and, in the middle of a rambling attempt to justify a recent climate crank call for a joint Australia-NZ Royal Commission on climate change manages to come out with the following:
Anyone who claims that the science on global warming is settled is wrong. There is now growing evidence that that the earth is not warming but cooling: since the 1970s the glaciers of the Arctic, Greenland, and the Antarctic have been growing, and since 1998 average world temperatures have been falling with 2006 cooler than 2005 and 2007 cooler still.
This may be what Muriel fervently believes, but it is also completely untrue. So untrue, in fact, that saying it in an attempt to influence public policy amounts to lying. Sadly, in the echo chamber of truthiness around her web site, she gets taken at face value. Out in the wider world, it simply leaves her credibility in tatters.
Continue reading “Being economical with the truth, or lying through her teeth?”