Category: Climate science

Pump up the volume (before the ice is gone)

Early results from the European Space Agency’s Cryosat-2 satellite, launched in 2010, suggest that the Arctic sea ice volume in summer is currently being lost at the rate of 900 cubic kilometres per year, Robin McKie reports in The Guardian. By combining Cryosat data with other sources they have concluded that there has been a dramatic reduction in sea ice volume over the last eight years:

In winter 2004, the volume of sea ice in the central Arctic was approximately 17,000 cubic kilometres. This winter it was 14,000, according to CryoSat.

However, the summer figures provide the real shock. In 2004 there was about 13,000 cubic kilometres of sea ice in the Arctic. In 2012, there is 7,000 cubic kilometres, almost half the figure eight years ago. If the current annual loss of around 900 cubic kilometres continues, summer ice coverage could disappear in about a decade in the Arctic.

Ten years (or less) ’til its gone in summer. I hate to say I told you so, but…

Continue reading “Pump up the volume (before the ice is gone)”

Arctic sea ice forecast: it’s going to be tough to stay cool

Bad news from the Arctic is piling up as we head into the last few weeks of the melting season. The various measures of sea ice area, volume and extent are plummeting towards a new record minimum. I have therefore reviewed the history of Arctic sea ice melting seasons since 2007, and compiled my own forecast of how the rest of the year is going to pan out. Remember, you read it here first…

When Arctic sea ice area sets a new record low in the next couple of weeks, the usual suspects ((Being Watts, Goddard, Bastardi, Jo Nova, Delingpole, the GWPF, Morano and their NZ poodle, Richard Treadgold.)) will say: “You can’t trust area, sea ice extent is the only valid metric“.

When Arctic sea ice extent sets a new record low in September, the following arguments will be run in parallel:

  • There will be a frantic search for a definition of extent in which a new record was not set
  • There will be a complaint that the satellite record has been blighted by the failure of a sensor and the calibrations needed to get a new sensor in operation have corrupted the record ((With added bonus insinuations of fixing and fraud by “warmist” scientists.))
  • It will be claimed that it was all caused by the major Arctic storm that hit in August, and thus can’t be attributed to global warming ((In 2007, the record low was all down to winds, remember?))
  • It’s cyclical — it’s all happened before, in the 1930s ((Or pick a date (any date), based on an old press clipping reporting anecdotal evidence of ice loss.)), and is therefore nothing unusual
  • That it’s irrelevant, because it’s not global and not happening where anyone lives so can’t possibly matter.

When the sea ice extent and area anomalies blow out to record levels in early October because of the delayed freeze-up, there will be silence.

When the re-freeze starts, and the Arctic basin is covered in ice once more (early December), Anthony Watts will report on the record rate of ice formation, calling it a “stunning recovery“.

When a cold spell hits the Eastern US and/or Western Europe in December/January, caused by a major Arctic Oscillation excursion and the resulting big slow-moving loops in the polar jetstream ((A result of massive heat loss from the Arctic Ocean during the refreeze, see the work of Jennifer Francis, reported earlier.)), the usual suspects will cackle loudly that global warming has suffered another mortal blow from which it will never recover.

Long range forecast for the next five years, until the Arctic Ocean is ice free in summer? Rinse and repeat.

Greenland’s extraordinary summer #2: still melting

Petermann20120806

Greenland’s extraordinary summer is far from over. The ice island that broke off the Petermann glacier tongue last month — now dubbed PII-2012 — is edging its way out into the Nares Strait between Greenland and Ellesmere Island, as this satellite image, snipped from NASA’s fabulous daily Arctic Mosaic shows. For updates on events in Nares Strait, check out Dr Andreas Muenchow’s Icy Seas blog — he’s up there at the moment. Elsewhere on the great ice sheet, melting continues apace. Jason Box reports that ice sheet albedo has dipped again into record levels for the time of year, and there are reports of further extensive surface melting at the end of July. Box also reports that a recent update of the Greenland temperature record shows that current temperatures are unprecedented in at least the last 172 years. There’s also excellent coverage of the summer at Greenland melting.

Meanwhile, and rather unsurprisingly, New Zealand’s little band of climate deniers are insisting that there’s nothing special going on up North. And, equally unsurprisingly, they’re totally wrong.

Continue reading “Greenland’s extraordinary summer #2: still melting”

Favourite worst nightmare

The summer melt season in the Arctic is approaching its annual climax — the sea ice minimum, due in September — and the picture is beginning to look grim. Sea ice extent and area are tracking 2007’s record-setting melt, ice volume is at record lows for the time of year, and the ice is looking very fragmented, making it vulnerable to rapid melting events. To make matters worse, a large storm is brewing over the Arctic ocean, and is likely to create a surge of ice loss. 2012 could be heading towards breaking 2007’s record minimum, and that’s bad news for the entire northern hemisphere.

Continue reading “Favourite worst nightmare”

Greenland’s extraordinary summer: melting records and ice island setting sail

Petermann2012203

July has been an amazing month in Greenland. The Petermann Glacier has given birth to another huge ice island — taking its terminus further back up its fjord than at any time in the last 100 years (at least), record high temperatures have been recorded at the summit of the ice sheet at 3,200 meters, initiating surface melt over the whole vast sheet, ice sheet albedo has plummeted, and the Jakobshavn Isbrae’s calving front has retreated into the ice sheet.

The best coverage of the Petermann event, as on most matters to do with the Arctic summer and sea ice melting season is to be found at Neven’s Arctic Sea Ice blog. It’s well worth reading the comments under the Petermann post there, to get a really informative picture of what’s being going on. Here’s a description by Dr Andreas Muenchow ((Andreas provides great coverage of the Petermann glacier at his blog — perhaps unsurprisingly, as he’s on his way up there to recover instrumentation soon.)) of what the calving would have been like:

I described the Petermann calving to some media folks as a gentle and very quiet affair similar to a rubber duckie pushed out to sea from the deck of a flat pool.

Some duckie, some pool…

Illulisatanimated2012203Further south, the the “root” of the Jakobshavn Isbrae has enlarged significantly, with the calving front of Greenland’s most productive glacier retreating further into the ice sheet. The “blink” image I’ve cobbled together (left) shows day 203 of this year compared with day 202 of last year ((Source: 2012, 2011.)). The difference is large and very obvious. Greenland specialist Dr Jason Box was flying out of Ilulisat shortly after the retreat earlier this month, and snapped the photo below out of the window of his plane. As he commented on Facebook, it looks like the glacier has divided into two streams.

BoxGreenlandIllulisat

Up at the summit of the Greenland ice sheet at 3,200 metres, a new high temperature record of 3.6ºC was set on July 16, hard on the heels of four days in row of temperatures above freezing, from July 11 to 14. Considering that temperatures above zero had only been recorded four times in the preceding 12 years, this amounted a remarkable heatwave, and triggered an astonishing melt record.

Greenlandmelt2012

This NASA graphic shows how the melting surface, shown in shades of red, spread over the whole surface of the ice sheet from July 8 to July 12. This amounts to “the largest extent of surface melting observed in three decades of satellite observations”, according to NASA. The last such melting event occurred in 1889, and ice cores show that they occur every 150 to 250 years. However, given the steady increase in melt area over the last decade, and the precipitous drop in ice sheet albedo (see below), especially at high altitudes, it may not be 150 years before such a melt happens again.

GISalbedo201207

The last time I looked at this extraordinary summer in Greenland, it was to report Jason Box‘s view that “it is reasonable to expect 100% melt area over the ice sheet within another similar decade of warming”. It took two weeks to come true. Forgive me if I find that alarming.