Relevant and even prescient commentary on news, politics and the economy.

Ice melting takes some thought…

From reader rjs comes this list of links in paragraph form on records being passed over time on Arctic sea ice and Greenland glaciers melting.  New radar allows for a variety of measurements, one being a way to measure ice thickness in the Arctic.  Edited lightly for readability:

It has been an exciting week for those among us who have dedicated their lives to watching ice melt, since every day this past week has set a new record low for the amount of arctic ice remaining…arguably, the old 2007 record may have fallen on August 24th, when the japanese aerospace agency’s arctic sea ice monitor recorded their new low sea-ice extent of 4,189,375 square kilometers, but August 26th marks the date the record was broken according to our National Snow and Ice Data Center, when the arctic sea ice extent fell to 1.58 million square miles, or 4.10 million square kilometers, which was 70,000 square kilometers below the previous record low daily sea ice extent set on September 18 of 2007..

To put those numbers in perspective, that is about a million more square miles of the arctic now open than was during the 1979-2000 average, or about an area as large as texas and alaska combined…this is remarkable in that the record was broken so early in the arctic ice melt season, and that ice will continue to melt and set new low extents every day at least till mid september, also remarkable in that the melting is accelerating this late in the season, ie, more ice has been melting each day than the day before, rather than slowing down as it usually would in late august, with a daily rate of loss 50% higher than it was in 2007.

The year the old record was set; normally, at this time of year, we’re losing about 15,000 sq miles of ice a day; this year the rate of ice loss continues at 29,000 a day, nearly twice the average…of course, these newly opened areas in the arctic sea will absorb even more heat than iced over areas that would reflect the sun’s rays back into the atmosphere… the adjacent illustration from the NSIDC graphs the ice extent during the melt seasons since 1979, the beginning of the satellite record, on the date the new record was set; this year to that date is in dark blue, the previous record year 2007 is a green dash, 1980 is orange, the average of all data is in light blue, with the 1979-2000 average as a solid black line, and the gray area indicating the two standard deviation range of the data.

 NSIDC also data shows that all 6 lowest ice extents in the satellite record have occurred over the past 6 years. Physicist Stuart Staniford, observing that the annual   change in arctic sea ice was not linear, fitted a quadratic equation to the rate of loss, which shows the arctic would hit zero ice in 2017 and  his further extrapolations show the Arctic ice free for six months out of the year by 2025

Peter Wadhams, professor of ocean physics at Cambridge, believes arctic ice is on the brink of collapse and that it will be gone in 3 years….you may recall that we discussed one of the effects of a warmer arctic sea on methane release this past winter; that the arctic contains copious amounts of methane-hydrates frozen at high pressure on the seabed, and that as the ocean warmed, russian scientists observed massive plumes of methane bubbling to the surface of the arctic ocean, some as large as 1000 meters in diameter…methane is known to be a potent greenhouse gas, considered 25 times as potent a heat-trapping gas as CO2 over a 100 year time horizon, but 72 times as potent over 20 years, so the release of methane enhances the warming feedback, accelerating the process….to see this visually, we have 3 arctic projections showing methane releases from 2002, 2010 and 2011 at the end of our January 8th blog post; the change over just a few years is really quite stunning…

It’s not just the ice in the arctic ocean that’s been melting…last week, analysis of satellite photographs confirmed that greenland had already also exceeded it’s one season melt record on August 8th, almost a full month before the normal end of the melt season on that large island…the record ice loss had been anticipated after an unprecedented 4 day thaw over 97% of the ice sheet in mid-july; also, a nearly obscure last item in the NSIDC’s first July Arctic Sea Ice News & Analysis bulletin noted that the snow cover in the northern hemisphere in June had melted to such an extent that it beat the 45 year record low a month early, breaking the 2010 record by 1 million square kilometers…much of this snowpack loss is from higher elevations, where downstream cities depend on a continuous release of ice-melt for their water supply

Arguably, the loss of seasonal of snow & ice on land masses is a more serious problem than over the arctic sea, because it adds to sea level rise, and most of the world’s major port cities are built at sea level; you might recall the illustration we used when discussing greenland’s ice-loss in 2010: if all the snow pack loss from greenland that year were to be dumped at once on low lying new jersey, it would cover new jersey with 257 feet of snow … James Hansen, the head of NASA’s goddard institute, believes that a 5 meter sea level rise is possible this century as the Greenland antarctic ice sheets rapidly melt…

Sea ice in the Arctic and new data from Cryo-Sat-2

Hi folks…coming back on line from experiences in hospital services (not mine) and found this Guardian article on something we haven’t followed closely in posts.  
From the Guardian comes this note on the preliminary data of the new Cryo-Sat-2 probe on Arctic ice volumes:

Sea ice in the Arctic is disappearing at a far greater rate than previously expected, according to data from the first purpose-built satellite launched to study the thickness of the Earth’s polar caps.
Preliminary results from the European Space Agency‘s CryoSat-2 probe indicate that 900 cubic kilometres of summer sea ice has disappeared from the Arctic ocean over the past year.

CryoSat-2 is the world’s first satellite to be built specifically to study sea-ice thickness and was launched on a Dniepr rocket from Baikonur cosmodrome, Kazakhstan, on 8 April, 2010. Previous Earth monitoring satellites had mapped the extent of sea-ice coverage in the Arctic. However, the thickness of that ice proved more difficult to measure.
The US probe ICESat made some important measurements of ice thickness but operated intermittently in only a few regions before it stopped working completely in 2009. CryoSat was designed specifically to tackle the issue of ice thickness, both in the Arctic and the Antarctic. It was fitted with radar that can see through clouds. (ICESat’s lasers could not penetrate clouds.) CryoSat’s orbit was also designed to give better coverage of the Arctic sea.

“Before CryoSat, we could see summer ice coverage was dropping markedly in the Arctic,” said Rapley. “But we only had glimpses of what was happening to ice thickness. Obviously if it was dropping as well, the loss of summer ice was even more significant. We needed to know what was happening – and now CryoSat has given us the answer. It has shown that the Arctic sea cap is not only shrinking in area but is also thinning dramatically.”
Graphic: shrinking ice caps

Arctic sea ice melt futures

Arctic Sea Ice measurements are still being reported by the National Snow and Ice Data Center but are not much noted in the national press.

Arctic sea ice extent in December 2011 averaged 12.38 million square kilometers (4.78 million square miles). This is the third lowest December ice extent in the 1979 to 2011 satellite data record, 970,000 square kilometers (375,000 square miles) below the 1979 to 2000 average extent.

Animated map is here.

Previous Angry Bear posts on sea ice are herehere, and here.