Tag: sea ice

The Climate Show: Beta 1

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Introducing The Climate Show, the first (beta 1) stab at a web-based “radio with pictures” programme about climate news science, policy, politics and solutions. It’s the brainchild of KIWI FM’s Radio Wammo breakfast host Glenn Williams, one of the most innovative young broadcasters in New Zealand, and he’s roped me in to add, er, something or other… 😉

The show was recorded last week via Skype video conference, and we discussed new temperature records, the state of the Arctic, chatted with Kevin Cudby about his new book From Smoke To Mirrors, recommended the Skeptical Science web site and iPhone app, and then discussed some recent developments in solar photovoltaic technologies. It’s available at Youtube, as a podcast via iTunes, and will soon have its own site at theclimateshow.co.nz . You can follow the show on Twitter at @TheClimateShow. We’re aiming to record a programme every couple of weeks to begin with. All feedback welcome — what do you think of the show and what would you like us to cover? Any guests you’d particularly like us to feature (NZ and worldwide)? And if you like the show, tell your friends… Links to the stuff we talk about below the fold.

The Climate Show (audio)

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Arctic report card 2010: a one-way trip to warming

Last week NOAA released the 2010 update of its Arctic Report Card, covering the 2009/10 winter season and 2010 summer sea ice minimum. It makes for sobering reading. Greenland experienced record high temperatures, ice melt and glacier area loss, sea ice extent was the third lowest in the satellite record, and Arctic snow cover duration was at a record minimum. It’s worth digging through the whole report — it’s concise, well illustrated and referenced back to the underlying research — but a couple of things struck me as really important.

 

The first is the dramatic melting seen in Greenland this summer. From the Greenland report card:

Summer seasonal average (June-August) air temperatures around Greenland were 0.6 to 2.4°C above the 1971-2000 baseline and were highest in the west. A combination of a warm and dry 2009-2010 winter and the very warm summer resulted in the highest melt rate since at least 1958 and an area and duration of ice sheet melting that was above any previous year on record since at least 1978.

And


Abnormal melt duration was concentrated along the western ice sheet (Figure GL3), consistent with anomalous warm air inflow during the summer (Figure GL1) and abnormally high winter air temperatures which led to warm pre-melt conditions. The melt duration was as much as 50 days greater than average in areas of west Greenland that had an elevation between 1200 and 2400 meters above sea level. In May, areas at low elevation along the west coast of the ice sheet melted up to about 15 days longer than the average. NCEP/NCAR Reanalysis data suggest that May surface temperatures were up to 5°C above the 1971–2000 baseline average. June and August also exhibited large positive melting day anomalies (up to 20 days) along the western and southern ice sheet. During August temperatures were 3°C above the average over most of the ice sheet, with the exception of the northeastern ice sheet. Along the southwestern ice sheet, the number of melting days in August has increased by 24 days over the past 30 years.

Not good news for the ice sheet. The atmosphere report card draws attention to the impact Arctic warming is having further south, dubbing it the warm arctic/cold continents pattern (WACC).

While 2009 showed a slowdown in the rate of annual air temperature increases in the Arctic, the first half of 2010 shows a near record pace with monthly anomalies of over 4°C in northern Canada. There continues to be significant excess heat storage in the Arctic Ocean at the end of summer due to continued near-record sea ice loss. There is evidence that the effect of higher air temperatures in the lower Arctic atmosphere in fall is contributing to changes in the atmospheric circulation in both the Arctic and northern mid-latitudes. Winter 2009-2010 showed a new connectivity between mid-latitude extreme cold and snowy weather events and changes in the wind patterns of the Arctic; the so-called Warm Arctic-Cold Continents pattern.

So now you know where the WACCy winter weather’s coming from


Gone for good: Arctic Ocean ice free all year by the 2040s?

A few days ago I used a combination of Arctic sea ice volume data from the University of Washington’s PIOMAS model and NSIDC sea ice extent numbers to project that the Arctic Ocean would be effectively ice-free in late summer within ten years. The key to that exercise was the rate at which the volume of sea ice has been declining — 350 km3 per year over the last 30 years for the full dataset, 410 km3 per year over the last 20, and 740 km3 over the last decade at summer minimum. The rate of volume decline has obviously been increasing. Using those numbers to project ice extent in the future is one thing, but they also tell us something interesting about the overall Arctic heat budget — and we can use that to make a rough guess about when the Arctic will become ice-free year round. The answer is surprising…

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Five years (threnody for Arctic sea ice)

Earlier this month the US National Snow & Ice Data Center issued its analysis of this year’s Arctic sea ice minimum — at 4.60 million km2 on September 19, the third lowest extent in the satellite record. However extent (defined here) doesn’t tell you everything about the state of the ice — according to the University of Washington’s PIOMAS ice model 2010 managed to set a new record low for sea ice volume.

In terms of the future of the Arctic sea ice, the volume of ice remaining at minimum is a crucial metric because it represents the size of the heat budget buffer between an ocean with a perennial floating ice cap and one that’s seasonally ice-free. For the Arctic to be ice free in summer, that buffer has to disappear, or become a lot smaller. I’ve been writing about sea ice volume for some time, and considered the overall Arctic heat budget in this post a couple of years ago, so news of the new low volume prompted me to think about what it might mean for the extent metric over the next few years. To do that, I downloaded the NSIDC’s September monthly average extent for the last 21 years, and plotted that against the PIOMAS model’s September average monthly volume (kindly supplied by Jinlun Zhang). Here’s what the data looks like when you plot it on the same chart.

SeaIceData.png

The red line at the bottom, labelled “thickness”, is what you get when you divide volume by extent, and that too has been in decline, reflecting the fact that the loss of volume has been happening faster than the reductions in extent.

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All around the world

The Arctic Ocean has been circumnavigated by sailing vessels in a single season for the first time. The Norwegian trimaran Northern Passage reports that it has passed 74ÂșN, traditionally regarded as the eastern end of the NW Passage, and is now sailing into Baffin Bay heading for Pond Inlet. The Russian boat Peter 1is reported to be about one hour’s sailing ahead of them. In their blog post marking the milestone, Thorleif Thorleifsson and BĂžrge Ousland provide this telling comment:

It is, unfortunately, the dramatic changes in Arctic sea ice conditions in recent years that have made this trip possible. On the time of Roald Amundsen it took five to six years to complete the same distance, due to the extremely difficult and demanding ice conditions. Now we have proven that it is possible to make the voyage in a 31-foot fibreglass sailing boat, equipped with a 10 horsepower outboard motor for emergencies. This shows how dramatic and how fast these changes are happening. The changes that we are witnessing will influence climate on a global scale, in addition to the whole range of animal life in the Arctic – especially seals and polar bears, whose lives are dependent on the sea ice.

It is our hope that our voyage will be seen as a strong, visible symbol of the scale and the speed of these changes.

Congratulations to both teams for their remarkable achievement. Given that the first circumnavigation by a sailing vessel was made by the French yacht Vagabond over two seasons as recently as 2002-2003, it’s clear that the pace of change in the Arctic is not slackening. Reflecting that, the Arctic Forum — a meeting of countries with claims to Arctic territory — is currently underway in Moscow. The Independent reports that the mood of the meeting is “conciliatory”, but the pressure to establish territory is growing as the rush to exploit oil, gas and mineral resources intensifies (see BBC for more).

[Updated] And to remind us that what’s at stake in the Arctic is a great deal more than a few billion barrels of oil, Yahoo News carries an IPS story on Arctic warming and the methane problem. If the average global warming is held to 2ÂșC (which doesn’t seem likely under present policy settings), the Arctic will warm much faster. NSIDC director Mark Serreze is characteristically blunt:

“I hate to say it but I think we are committed to a four- to six-degree warmer Arctic,” Serreze said.

If the Arctic becomes six degrees warmer, then half of the world’s permafrost will likely thaw, probably to a depth of a few metres, releasing most of the carbon and methane accumulated there over thousands of years, said Vladimir Romanovsky of the University of Alaska in Fairbanks and a world expert on permafrost. [
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That would be catastrophic for human civilisation, experts agree.

In other words, we have very good reasons to believe that settling for a 2ÂșC target would be to acquiesce in a global disaster. We can only hope for two things: that the climate commitment (the inevitable warming “in the pipeline”) does not push the Arctic into a huge release of methane, and that the world’s leaders wake up to the real scale and urgency of the problem. For all our sakes

[Oasis]