Tag: Greenland

Greenland ice melt spreads northwest

This animation shows Greenland’s ice mass loss over 2003 to 2009, estimated by combining data from NASA’s GRACE satellites with high precision GPS measurements of “rebound” in the underlying rock as the weight of ice is removed. The lightest blue shows low levels of mass loss, black the highest. From the University of Colorado press release:

“Our results show that the ice loss, which has been well documented over southern portions of Greenland, is now spreading up along the northwest coast,” said Shfaqat Abbas Khan, lead author on a paper that will appear in Geophysical Research Letters.

Khan goes on to suggest what this might imply for the future:

If this activity in northwest Greenland continues and really accelerates some of the major glaciers in the area — like the Humboldt Glacier and the Peterman Glacier — Greenland’s total ice loss could easily be increased by an additional 50 to 100 cubic kilometers (12 to 24 cubic miles) within a few years.

Another good reason to keep an eye on the Arctic this summer. Climate Progress has a very good overview of recent work on Greenland ice loss and its implications for sea level rise. Well worth a read, if not exactly comforting.

Marvellous distempered: the Copenhagen diagnosis

The Copenhagen climate conference (COP15) opens its doors in a little under two weeks. To update participants on the science of climate a new assessment report, The Copenhagen Diagnosis, was released yesterday, and it makes grim reading. Designed to inform “a target readership of policy-makers, stakeholders, the media and the broader public” about the evidence that’s emerged since the 2005 cut-off for the IPCC’s Fourth Report, it is especially strong on the accumulating signs of climate change as it happens.

Evidence of melting of the Greenland and Antarctic ice sheets supports a revision of the expected sea level rise by the end of the century: it “may well exceed” a metre. The rapid sea ice loss in the Arctic in recent years highlights the risks of methane releases from permafrost, but the most direct message is that with global carbon emissions surging up to and beyond the highest of the IPCC’s scenarios, and with pretty strict limits on the amount of carbon we can add to the atmosphere and stay under a 2ºC rise, we need to start cutting emissions soon.

Here’s what the emissions growth looks like:

CopCO2emissions.jpg

And here’s what we need to do to stay under 2ºC:

CopDiagtargets.jpg

It’s a simple enough message. The longer we leave it before starting to cut emissions, the steeper the cuts will need to be. And there’s an obvious corollary: steep cuts will be more expensive. Inaction now means more cost in the future. Where does that leave any government promising to “balance the economy and the environment”?

Below the fold: the full executive summary.

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Titanic days

Awesome (defined as extremely impressive or daunting; inspiring great admiration, apprehension, or fear) time-lapse pictures of the calving face of the great glacier at Ilulisat, Greenland pouring ice into the ocean — the single biggest ice discharge of any northern hemisphere glacier. Greenlanders reckon this is where the iceberg that sank the Titanic originated. The ice face is huge — the helicopter at the beginning of the clip gives some sense of scale — but the ice is actually 1,000 metres thick at that point. This clip is only an appetiser for the Extreme Ice Survey‘s James Balog providing more detail, and showing many more truly awe-inspiring images in a recent TED talk. Well worth 20 minutes of anyone’s time — as Balog says, it’s hard to ignore the evidence of what’s happening up North.

[Hat tip to Riatsala in a comment yesterday]

More than a metre

Sea level will rise by more than a metre by 2100 according to the authors of the third chapter in the World Wide Fund for Nature’s new Arctic report, introduced by Gareth a few days ago. Eric Rignot, one of the two authors of the chapter, is principal scientist for the Radar Science and Engineering Section at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.  The other author, Anny Cazenave, is an internationally renowned research scientist from France’s national centre for space studies.

The value of the chapter is that it draws together, authoritatively and coherently, the evidence that points to considerably more sea-level rise over this century than projected in the 2007 IPCC Fourth Report (AR4). Happily politicians are taking IPCC reports much more seriously than in the past, but they should not rest on them.  Their responsibility is to be up to date with what the science is saying now. The WWF report assesses the most recent science, and finds that the impacts of warming will be more severe than indicated by the IPCC.

What follows is a summary of the main points made by the chapter.

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(Arctic) Change is now

The World Wide Fund for Nature (WWF) has just published a new report on climate change in the Arctic — Arctic Climate Feedbacks: Global Implications [PDF], and it’s a fascinating read. Over the last two years I’ve blogged regularly on the changes being seen in the Arctic — sea ice reductions, melting of the Greenland ice sheet, the danger of increased carbon release from permafrost and sea floor methane hydrates, and the possible impacts on northern hemisphere weather patterns and climate. WWF’s report — written by some of the leading names in the field (including Serreze, Stroeve, Cazenave, Rignot, Canadell, and for the methane hydrate chapter Shakhova and Semiletov) — pulls together all those strands to paint a picture of a region undergoing rapid change. The authors provide a fully-referenced review of our current understanding of the processes at work as the pole warms, with chapters covering atmospheric circulation feedbacks, ocean circulation changes, ice sheets and sea level, marine and land carbon cycle feedbacks, and sea floor methane hydrates. It’s compelling stuff, and well worth reading in full, but for this post I want to focus on the excellent overview of methane hydrate feedbacks provided by Natalia Shakhova and Igor Semiletov.

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