eSci: "Planetary Emergency" New 2012 Arctic Sea Ice Record 18% Below 2007 Low

Arctic sea ice extent bottomed out at 3.41 million square kilometers (1.32 million square miles) on September 16, smashing the old record minimum of 4.17 million square kilometers (1.61 million square miles) set on September 18, 2007, according to the NSIDC. The 2007 record was set under ideal sunny and warm conditions for melting, but this summer's weather was only average for melting. The record collapse in sea ice extent happened this year because ice was very thin before the melt season began. Thick multi-year old sea ice is almost gone from the Arctic. The vast extent of open water this summer has allowed the Arctic ocean to adsorb large amounts of solar heat so ice thickness will not recover much this winter. Arctic sea ice is in a death spiral. One expert predicts that the Arctic ocean will be ice free in September 2015 or 2016.

NASA's Dr James Hansen, concerned about the destabilization of the climate and the triggering of additional feedback loops - such as large scale seabed methane release - by the loss of Arctic sea ice, declared a planetary emergency at a press conference held by Greenpeace.

“We are in a planetary emergency,” said Hansen, decrying “the gap between what is understood by scientific community and what is known by the public.”

NASA image showing September 16, 2012 record annual minimum NSIDC sea ice extent vs. 30 year average annual sea minimum ice extent. Sea ice extent maps are derived from data captured by the Scanning Multichannel Microwave Radiometer aboard NASA's Nimbus-7 satellite and the Special Sensor Microwave Imager on multiple satellites from the Defense Meteorological Satellite Program. Credit: NASA/Goddard Scientific Visualization Studio

Arctic Sea Ice Loss is Affecting Northern Hemisphere Weather

The long term decline in sea ice is affecting northern hemisphere atmospheric circulation patterns. One part of the Arctic ocean, the Barents Sea, has become increasingly ice free year round. This ice free area is a northern extension of warm Atlantic ocean water into the Arctic. Increased storminess has been observed in this region. The storms transfer large amounts of heat from the ocean to the Arctic atmosphere, often creating large warm bubbles of air called blocking highs. This summer, a warm blocking high led to the stunning event in Greenland where 97% of the surface of Greenland's ice cap melted. Blocking highs can divert cold air south into western Europe or eastern north America. Thus, the loss of sea ice is destabilizing the northern hemisphere's weather patterns.

The Barents sea has been stormy and Greenland has been frequently covered by a blocking high for 90 days of summer 2012. The effects of blocking highs over Greenland can be even more dramatic in winter, sending cold air and snow storms into the eastern U.S. while warming Greenland and the Arctic. The long-term predictions of sea ice area and extent made by the IPCC in 2007 were wildly optimistic compared to the observations of the past 5 years. Because ice acts as a reflective mirror, the loss of sea ice has a large positive feedback effect on Arctic and global warming. Open water takes up heat that ice formerly reflected back to space. Therefore the IPCC's predictions made in 2007 have seriously underestimated the severity of the rate and amount of Arctic and global warming.

IPCC Models Failed to Predict Rapid Sea Ice Extent Decline

However, the rapid decline of sea ice is fit by a simple exponential model applied to sea ice volume. The volume at the beginning on September 6, likely just before the minimum volume was reached, was well predicted by this empirical fit. If this fit continues to be predictive, sea ice volume will decline to zero in September 2015. Critics may rightly say that this fit is not based on physical theory. That may be true, but the complex models used by the IPCC clearly failed to incorporate a key physical process, so they are useless for prediction until the are corrected.
Will the loss of sea ice trigger increased methane emissions in the Arctic Ocean?

Disturbing reports of increasing methane levels in the Arctic ocean have been made by scientists for the past several years. No one knows how the warming sea waters will affect methane emissions from the shallow Siberian shelf where vast deposits of methane ice (known as clathrate) are located. Scientists have proposed very different models of Arctic seabed clathrate stability. Real Climate's David Archer summarized the position that CO2, not methane, is the primary climate change concern. Heat flow in undisturbed subsea sediments is very slow, so slow that it takes thousands of years for a heat pulse to affect buried clathrates.

What could happen to methane in the Arctic?

The methane bubbles coming from the Siberian shelf are part of a system that takes centuries to respond to changes in temperature. The methane from the Arctic lakes is also potentially part of a new, enhanced, chronic methane release to the atmosphere. Neither of them could release a catastrophic amount of methane (hundreds of Gtons) within a short time frame (a few years or less). There isn’t some huge bubble of methane waiting to erupt as soon as its roof melts.

And so far, the sources of methane from high latitudes are small, relative to the big player, which is wetlands in warmer climes. It is very difficult to know whether the bubbles are a brand-new methane source caused by global warming, or a response to warming that has happened over the past 100 years, or whether plumes like this happen all the time. In any event, it doesn’t matter very much unless they get 10 or 100 times larger, because high-latitude sources are small compared to the tropics.

The opposing point of view is that there are vertical pathways for methane release, heat transfer and fluid convection called taliks disrupting the undersea permafrost of the Siberian shelf. Destabilization of taliks could trigger rapid release of massive quantities of methane, according to some scientists.

Since the area of geological disjunctives (fault zones, tectonically and seismically active areas) within the Siberian Arctic shelf composes not less than 1-2% of the total area and area of open taliks (area of melt through permafrost), acting as a pathway for methane escape within the Siberian Arctic shelf reaches up to 5-10% of the total area, we consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. That may cause ∼12-times increase of modern atmospheric methane burden with consequent catastrophic greenhouse warming.

A recent ship report of methane emissions observed in the Laptev sea by Russian scientists needs to be put in context, written up and peer reviewed. At this point we don't know enough to know what it means.

According to the press-service of the expedition aboard The Viktor Buinitsky research vessel, the diameter of some of the ‘methane fields’ found in the northern part of the Laptev Sea exceeds 1 kilometre.