Climate & environment - Mar 8
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Arctic arch failure leads to sea-ice exodus
Kate Ravilious, New Scientist
EVERY winter the Arctic ice cap is penned in by curved barriers of ice spanning the straits that lead out of the Arctic Ocean. Now it seems that some of these ice arches are failing to form. The resulting exodus of sea ice into the Atlantic and Pacific could affect ocean circulation and marine life.
A team led by Ronald Kwok of the Jet Propulsion Laboratory in Pasadena, California, has studied satellite images of the Nares Strait - the narrow passage between Greenland and Ellesmere Island. For each of the last 13 years they noted when ice arches formed and how much sea ice escaped down the strait.
During most years, large blocks of sea ice clump together in mid-January to build one or two arches across the strait. The arches usually persist for around six months, acting as dams to prevent the ice from floating away.
Then in 2007, the warmest year on record in the Arctic, no arches formed and vast quantities of sea ice were lost. "Around 1 per cent of Arctic ice by area went down the Nares Strait that year; more than double the usual amount," says Kwok. The next year wasn't much better - only one weak arch formed and broke down after two months (Geophysical Research Letters, DOI: 10.1029/2009GL041872). Last year provided a brief respite, but so far in 2010 there is no sign of any arches in the strait.
Kwok and his colleagues suspect that higher temperatures are thinning Arctic ice, creating smaller and weaker blocks that are less effective at building arches...
(26 February 2010)
World's temperature record to be re-analysed
Michael McCarthy, Environment Editor, The Independent
The whole of the world's instrumental temperature record – millions of observations dating back more than 150 years – is to be re-analysed in an attempt to remove doubts about the reality of global warming.
The new analysis, an enormous task which will be carried out by several groups of scientists working independently in different countries, has been proposed by the UK Met Office in the wake of recent controversies over climate science, such as the "climategate" email affair at the University of East Anglia and revelations that the last report of the Intergovernmental Panel on Climate Change (IPCC) contained inaccuracies and exaggerations.
...The plan is for the entire global record of land-based air temperatures from 5,000 weather stations, which began before 1860, to be made freely available to anyone. It will then be reanalysed by at least three and possibly five groups of experts, whose different methods will be made transparent and open to scrutiny, and whose conclusions will be peer-reviewed.
The task is expected to take three years, and it is likely that its findings will form a core part of the next IPCC report, provisionally due in 2013 or 2014.
The Met Office stresses that it does not foresee that the new analyses will reveal any "substantial changes" from the basic conclusion in the last IPCC report, published in 2007, that the recent warming of the earth's climate is "unequivocal." Rather, it explains in its proposal document: "This effort will ensure that the datasets are completely robust and that all methods are transparent."
(25 Feb 2010)
In India, a Clear Victor on The Climate Action Front
Isabel Hilton, yale environment 360
On Feb. 19, a brief public statement in Delhi broke the news that the Special Envoy of the Prime Minister on Climate Change, the austere veteran bureaucrat, Shyam Saran, was to quit. The announcement came as a surprise: Saran was Delhi’s most senior climate official. He had earlier been entrusted by the prime minister, Manmohan Singh, with shepherding the controversial nuclear deal with the U.S. to a conclusion, then put in charge of India’s climate diplomacy. Only a few days before his resignation, Saran had chaired a meeting of India’s climate negotiators and domestic ministers to map out a post-Copenhagen strategy. What had gone wrong?
Within hours, India’s press was pointing to one man as the key to Saran’s departure: the relatively junior figure of the Minister for Environment and Forests, Jairam Ramesh.
Ramesh, though a minister, does not hold cabinet rank. Nor, until last year, was he a figure of international significance. In India’s complex, status-conscious political world, he ranked below the heavyweight Saran, a veteran foreign service official with a secure base in India’s powerful bureaucracy and the solid backing of India’s climate negotiating team.
But in the course of the last 12 months, from what might be rated, at best, a medium rung on Delhi’s ladder of power and influence, Jairam Ramesh has vanquished two senior rivals to emerge as the voice of India’s transformed climate policy. India had previously hung back, adamant that its prime responsibility was to give its citizens a better life, climate impacts notwithstanding. Today Delhi accepts that it is in India’s best interests to be constructively engaged in low-carbon policies both at home and internationally. And in the public battles that have been fought over India’s future responsibilities in climate change diplomacy, it is Ramesh who has triumphed...
(1 March 2010)
Is Arctic methane on the move?
RealClimate, The Guardian
Methane is like the radical wing of the carbon cycle, in today's atmosphere a stronger greenhouse gas per molecule than CO2, and an atmospheric concentration that can change more quickly than CO2 can. There has been a lot of press coverage of a new paper in Science this week called "Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf", which comes on the heels of a handful of interrelated methane papers in the last year or so. Is now the time to get frightened?
No. CO2 is plenty to be frightened of, while methane is frosting on the cake. Imagine you are in a Toyota on the highway at 60 miles per hour approaching stopped traffic, and you find that the brake pedal is broken. This is CO2. Then you figure out that the accelerator has also jammed, so that by the time you hit the truck in front of you, you will be going 90 miles per hour instead of 60. This is methane. Is now the time to get worried? No, you should already have been worried by the broken brake pedal. Methane sells newspapers, but it's not the big story, nor does it look to be a game changer to the big story, which is CO2.
For some background on methane hydrates we can refer you here. This weeks' Science paper is by Shakhova et al, a follow on to a 2005 GRL paper. The observation in 2005 was elevated concentrations of methane in ocean waters on the Siberian shelf, presumably driven by outgassing from the sediments and driving excess methane to the atmosphere. The new paper adds observations of methane spikes in the air over the water, confirming the methane's escape from the water column, instead of it being oxidized to CO2 in the water, for example. The new data enable the methane flux from this region to the atmosphere to be quantified, and they find that this region rivals the methane flux from the whole rest of the ocean.
What's missing from these studies themselves is evidence that the Siberian shelf degassing is new, a climate feedback, rather than simply nature-as-usual, driven by the retreat of submerged permafrost left over from the last ice age. However, other recent papers speak to this question.
Westbrook et al 2009, published stunning sonar images of bubble plumes rising from sediments off Spitzbergen, Norway. The bubbles are rising from a line on the sea floor that corresponds to the boundary of methane hydrate stability, a boundary that would retreat in a warming water column. A modeling study by Reagan and Moridis 2009 supports the idea that the observed bubbles could be in response to observed warming of the water column driven by anthropogenic warming...
(8 Mar 2010)
Methane Releases from Arctic Shelf May Be Much Larger and Faster Than Anticipated
University of Alaska, Fairbanks, ScienceDaily
A section of the Arctic Ocean seafloor that holds vast stores of frozen methane is showing signs of instability and widespread venting of the powerful greenhouse gas, according to the findings of an international research team led by University of Alaska Fairbanks scientists Natalia Shakhova and Igor Semiletov.
The research results, published in the March 5 edition of the journal Science, show that the permafrost under the East Siberian Arctic Shelf, long thought to be an impermeable barrier sealing in methane, is perforated and is leaking large amounts of methane into the atmosphere. Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.
"The amount of methane currently coming out of the East Siberian Arctic Shelf is comparable to the amount coming out of the entire world's oceans," said Shakhova, a researcher at UAF's International Arctic Research Center. "Subsea permafrost is losing its ability to be an impermeable cap."
Methane is a greenhouse gas more than 30 times more potent than carbon dioxide. It is released from previously frozen soils in two ways. When the organic material -- which contains carbon -- stored in permafrost thaws, it begins to decompose and, under oxygen-free conditions, gradually release methane. Methane can also be stored in the seabed as methane gas or methane hydrates and then released as subsea permafrost thaws. These releases can be larger and more abrupt than those that result from decomposition.
...The East Siberian Arctic Shelf is a methane-rich area that encompasses more than 2 million square kilometers of seafloor in the Arctic Ocean. It is more than three times as large as the nearby Siberian wetlands, which have been considered the primary Northern Hemisphere source of atmospheric methane. Shakhova's research results show that the East Siberian Arctic Shelf is already a significant methane source: 7 teragrams yearly, which is equal to the amount of methane emitted from the rest of the ocean. A teragram is equal to about 1.1 million tons.
Earlier studies in Siberia focused on methane escaping from thawing terrestrial permafrost. Semiletov's work during the 1990s showed, among other things, that the amount of methane being emitted from terrestrial sources decreased at higher latitudes. But those studies stopped at the coast. Starting in the fall of 2003, Shakhova, Semiletov and the rest of their team took the studies offshore. From 2003 through 2008, they took annual research cruises throughout the shelf and sampled seawater at various depths and the air 10 meters above the ocean. In September 2006, they flew a helicopter over the same area, taking air samples at up to 2,000 meters in the atmosphere. In April 2007, they conducted a winter expedition on the sea ice.
They found that more than 80 percent of the deep water and greater than half of surface water had methane levels more than eight times that of normal seawater. In some areas, the saturation levels reached at least 250 times that of background levels in the summer and 1,400 times higher in the winter.
(5 Mar 2010)
Climate scientists must be ruthlessly honest about data
David Colquhoun, The Guardian
I'm not a climate scientist, but I am concerned about the reputation of science and scientists. One motive for going into science for me was that it is one of the few jobs where you get rewarded for telling the truth.
So it was painful to watch the trust of the public in science, already dented, taking another crushing blow when the emails stolen from the University of East Anglia were revealed. We'll probably never know exactly what the emails meant, but we can say that the matter was handled very badly indeed. Phil Jones, head of the Climatic Research Unit, should have been immediately on every TV station, explaining what he meant. By going to ground, and by denying Freedom of Information Act requests, the university gave the impression of guilt, quite regardless of whether there is really anything to hide. That brings the university into disrepute: it is a matter for resignations.
I have never come across anything in my own field that would qualify as fraud, or even dishonesty (well just once it was close), and I have never been asked by an editor to come to a particular decision when reviewing a paper. Our analysis programs are free, on the web.
That is why I was deeply shocked when Jones told the Commons science and technology committee that practices like keeping original data, and analysis programs, secret were "standard practice" among climate scientists. "Maybe it [openness] should be, but it's not." The Institute of Physics submission to the parliamentary inquiry which spoke of "worrying implications ... for the integrity of scientific research in this field" was damning but spot on, and a credit to science.
A recent analysis of verified cases of misconduct in the US suggested that one in 100,000 scientists per year are guilty, but other ways of counting give larger numbers. For example, if asked, around two in 100 scientists claim to be aware of misconduct by someone else. The numbers aren't huge but they are much bigger than they should be...
(4 Mar 2010)