Surface temperature anomaly for the region extending from 64oN to 90oN, from 1880 through 2011, in degrees Centigrade above or below the temperature during the 1951-1980 base period.  

The annual mean surface temperature (land and air) for the region north of 64oN (the Arctic Circle is at 66° 33′N) in 2011 was 2.28° C above the 1951-1980 base period, beating 2010′s record of 2.11° C.  Temperatures in the region have been rising rapidly since the late 1970s and have not dropped below the long-term mean since 1992 — nearly 20 years.

Even with the cooling effects of a strong La Niña influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record – and the warming is especially concentrated in the Arctic.

Annual global surface temperature anomalies, 2011.  The largest and most extensive
warming (indicated in shades of red) was concentrated in the Arctic.
Source: NASA Goddard Institute for Space Studies.

NASA’s James Hansen expects record-breaking global average temperatures in the next two to three years because solar activity is on the upswing and the next El Niño will increase tropical Pacific temperatures. The warmest years on record so far were 2005 and 2010, in a virtual tie.

The carbon dioxide level in the atmosphere was about 285 parts per million in 1880, when the GISS global temperature record begins. By 1960, the average concentration had risen to about 315 parts per million. Today it exceeds 390 parts per million and continues to rise at an accelerating pace.

Rising temperatures are being accompanied by a decline in Arctic ice volume.

Ice volume for December 2011 was 12,230 km³ , 47% lower than the maximum in 1979, 37% below the mean and 1.6 standard deviations from trend. PIOMAS  ice volume for September 2011 was 380 km³ lower than the previous record of 2010, but this difference is within the estimated uncertainty of PIOMAS. The same appears to be true for December 2011 as well – ice volume is lower but within the range of uncertainty – as the University of Washington’s Polar Science Center reports 2011 volume is lower than the previous record of 2010.

Even more import than ice extent, Arctic sea ice volume is showing record lows.

The University of Washington’s Polar Science Center reports monthly averaged ice volume for July 2011 was 51% lower than the mean over the 1979-2010 period, 62% lower than the maximum in 1979, and 2.5 standard deviations below the trend.

New research from MIT finds that Arctic sea ice is thinning, on average, four times faster than the models used in the 2007 IPCC Forth Assessment Report indicate – and it’s drifting away twice as rapidly. The Fourth Assessment Report forecast an ice-free Arctic by 2100; we now expect it to happen several decades earlier.

Joseph Romm at Science Progress says we can expect Arctic sea ice to crash by two thirds by the 2030s and then collapse to near-zero shortly thereafter — unless we cut global GHG emissions about 60% to 70% almost immediately and then follow up with more cuts. That simply is not going to happen.

Not only will humans continue to spew GHG emissions. Mother Nature is starting to kick in, too.  Sea ice is just the canary in the coal mine.

Carbon emission (in billions of tons of carbon a year) from thawing permafrost.

In assessing the global warming impacts of melting permafrost, the NSIDC study that resulted in the graph above doesn’t even incorporate the CO2 released by the permafrost as feedback into its warming model, and further assumes that all of the permafrost carbon would be released as CO2 and none as methane. Methane is 25 times as potent a heat-trapping gas as CO2 over a 100 year time horizon, but 72 times as potent over 20 years.   The study warns:

The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO2 concentration.

Setting atmospheric CO2 target – any target, no matter how inadequate to avert climate catastrophe – is no longer even on the international political agenda, is no longer even imaginable as part of the U.S. political agenda. Actually doing anything, voluntarily, to achieve any such target is inconceivable, as that would require that we begin to dismantle industrial civilization.

We’re approaching the end of the play. Time for the deus ex machina.

The assessment finds that the past six years (2005–2010) have been the warmest period ever recorded in the Arctic. The higher surface air temperature are driving changes in the cryosphere. Two components of the Arctic cryosphere – snow and sea ice – are interacting with the climate system to accelerate warming in a feedback loop. Loss of ice and snow in the Arctic enhances climate warming by increasing absorption of the sun’s energy at the surface of the planet. Temperatures in the permafrost have risen by up to 2 °C and the southern limit of permafrost has moved northward in Russia and Canada- a trend which could result in dramatically increased emissions of carbon dioxide and methane. Melting ice could change large-scale ocean currents. Melting glaciers and ice sheets worldwide have become the biggest contributor to global sea level rise. Arctic glaciers, ice caps, and the Greenland Ice Sheet are contributing much more to global sea level rise than previously measured. High uncertainty surrounds estimates of future global sea level, with latest models predicting a rise of 0.9 to 1.6 m above the 1990 level by 2100. But, the assessment cautions, the combined outcome of these effects is not yet known. Interactions (‘feedbacks’) between elements of the cryosphere and climate system are particularly uncertain.

The assessment was done by the Arctic Monitoring and Assessment Programme (AMAP), an international organization headquartered in Norway. Member nations include the eight Arctic rim countries: Canada, Denmark/Greenland, Finland, Iceland, Norway, Russia, Sweden, and the United States. Other nations and organizations participate as well.

The National Snow and Ice Data Center (NSIDC) reports Arctic sea ice extent declined through April more slowly than usual, as cool conditions helped retain ice in Baffin Bay, between Canada and Greenland. Still, April 2011 continued the overall downward trend of the past thirty years, ranking fifth lowest in the satellite record. The two lowest years for April were 2007 and 2006.

University of Washington’s Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) model of sea ice volume shows continued very low ice mass in the Arctic compared to previous decades.

Joseph Romm at Climate Progress reports on a study showing the Greenland ice sheet has been losing mass over the last decade.

Greenland ice mass anomaly – deviation from the average ice mass over the 2002 to 2010 period.

]]> http://casafoodshed.org/archives/2011/05/05/arctic-cryosphere-change-dramatic/feed/ 0 http://casafoodshed.org/archives/2011/03/30/freshwater-content-of-arctic-ocean-increasing/ http://casafoodshed.org/archives/2011/03/30/freshwater-content-of-arctic-ocean-increasing/#comments Wed, 30 Mar 2011 20:17:55 +0000 jim http://casafoodshed.org/?p=6397 Scientists have found that the freshwater content of the upper Arctic Ocean has increased by about 20% since the 1990s. This corresponds to a rise of approximately 8,400 cubic kilometers and has the same magnitude as the volume of freshwater annually exported on average from this marine region in liquid or frozen form.

Around 10% of the global mainland runoff flows into the Arctic via the enormous Siberian and North American rivers in addition to relatively low-salt water from the Pacific. This freshwater lies as a light layer on top of the deeper salty and warm ocean layers and thus extensively cuts off heat flow to the ice and atmosphere. Changes in this layer are therefore major control parameters for the sensitive heat balance of the Arctic. The scientists expect that the additional amount of freshwater in the near-surface layer of the Arctic Ocean will flow out into the North Atlantic in the coming years. The amount of freshwater flowing out of the Arctic influences the formation of deep water in the Greenland Sea and Labrador Sea and thus has impacts on global ocean circulation.

The study, by researchers of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, is published in the journal Deep-Sea Research.

Imagine the vast, empty tundra in Alaska and Canada giving way to trees, shrubs and plants typical of more southerly climates. Imagine similar changes in large parts of Eastern Europe, northern Asia and Scandinavia, as needle-leaf and broadleaf forests push northward into areas once unable to support them. Imagine part of Greenland’s ice cover, once thought permanent, receding and leaving new tundra in its wake.

These three figures show the arrangement of arctic climate types using (a) observational data from 1950-99 and a combination of 16 climate-change models factoring in moderate greenhouse gas increases over the next 89 years (b) and (c). The climate types and vegetations in the arctic are abbreviated as Fi (ice cap/permanent ice cover); Ft (tundra); Ec (boreal continental/shrubs); Eo (boreal oceanic/needle leaf forests); Dc (temperate continental/needle leaf and deciduous tall broadleaf forests); and Do (temp

Changes to Arctic vegetation will follow shifts in the region’s climates. Tundra coverage is expected to shrink by 33 – 44% by the end of the century, while temperate climate types that support coniferous forests and needle-leaf trees would expand northward into the breach.

Lead author Song Feng says the vegetative changes could induce a positive feedback loop:

The expansion of forest may amplify global warming, because the newly forested areas can reduce the surface reflectivity, thereby further warming the Arctic. The shrinkage of tundra and expansion of forest may also impact the habitat for wildlife and local residents.

Tundra in Alaska and northern Canada would be reduced and replaced by boreal forests and shrubs by 2059. Within another 40 years, the tundra would be restricted to the northern coast and islands of the Arctic Ocean. The melting of snow and ice in Greenland following the warming will reduce the permanent ice cover. The ice would then be replaced by tundra. Also, increasing drought conditions could reduce the overall vegetation growth in the Arctic regions.

[E]arly–21st-century temperatures of Atlantic Water entering the Arctic Ocean are unprecedented over the past 2000 years and are presumably linked to the Arctic amplification of global warming.

The scientists say that waters at the Fram Strait – at the northern end of the Gulf Stream, between Greenland and the Norwegian archipelago of Svalbard – averaged 6 degrees Celsius (42.8°F) in recent summers.

The study showed that water from the Fram Strait has warmed roughly 3.5 degrees Fahrenheit in the past century. The Fram Strait water temperatures today are about 2.5 degrees F warmer than during the Medieval Warm Period, which heated the North Atlantic from roughly 900 CE to 1300 CE and affected the climate in Northern Europe, Greenland, and northern North America. Air temperatures in Greenland have risen roughly 7 degrees F in the past several decades.

Joseph Romm at Climate Progress has posted a key graph from the study:

Due to positive feedbacks between the ice, the Arctic Ocean and the atmosphere, the rate of Arctic sea ice decline has been accelerating – as seen is this graph from the University of Washington’s Polar Science Center:

As Arctic temperatures rise, summer ice cover declines, more solar heat is absorbed by the ocean and additional ice melts. Warmer water delays freezing in the fall, leading to thinner ice cover in winter and spring, making the sea ice more vulnerable to melting during the next summer.

Lead author Robert Spielhagen of the Academy of Sciences, Humanities and Literature in Mainz, Germany says the decline of Arctic sea ice is due in part to the warmer waters reaching the Arctic:

We must assume that the accelerated decrease of the Arctic sea ice cover and the warming of the ocean and atmosphere of the Arctic measured in recent decades are in part related to an increased heat transfer from the Atlantic.

Arctic sea ice is in a death spiral.

But not so fast! Their daily image update shows sea ice extent declining again. Sea ice extent has now fallen below that recorded on September 10.

The late-season dip shows up even better in this chart at the Japan Aerospace Exploration Agency website.

The IJIS website explains why their data may differ slightly from NSIDC’s:

In general, sea-ice extent is defined as a temporal average of several days (e.g., five days) in order to eliminate calculation errors due to a lack of data (e.g., for traditional microwave sensors such as SMMR and SSM/I). However, we adopt the average of two days to achieve rapid data release. The wider spatial coverage of AMSR-E enables reducing the data-production period.

Sea ice extent is defined as the areal sum of sea ice covering the ocean (sea ice + open ocean).

NSIDC reported sea ice extent on September 10, 2010 at 4.76 million km². According to IJIS, the minimum as of September 17 was 4.83 million km² – 120,000 km² below the September 10 extent of 4.95 million km² and just 130,000 km² above the minimum extent of 470,7813 km² reached on September 9, 2008.

Note that IJIS data on sea ice extent differs slightly from NSIDC data. The IJIS web site explains that they average the most recent two days of data rather than the more widespread methodology of averaging five days of data to “achieve rapid data release.” But this wouldn’t seem to explain why their numbers are higher than NSIDC’s.

Ice extent has been falling more than 50,000 km² a day for the past four days.  If that decline keeps up for just a couple more days, the 2010 minimum extent would dip below the 2008 mark and become the second lowest ever recorded.

Dot Earth has posted notes on the voyage by Tschudi Shipping:

1. Ice with low density (broken up) was encountered on two separate, short parts of the passage . . .

2. The vessel did not stop at all during the passage and kept an average speed of above 12 knots.

Present position, [via] yesterday’s statement from the Captain, heading due south having passed the Bering Strait enroute to China, estimated time of arrival September 27.

3. The vessel which has Hong Kong flag but is Danish owned and commercially operated by Nordic bulk Carriers, Copenhagen Denmark will most likely pick up a cargo in the Far East and return to the Atlantic via the southern routes . . .

The significance of this passage is that it shows that the Northern Sea Route can be an economical alternative sailing route even for relatively low value cargoes as iron ore concentrate. It provides resource companies (minerals and metal but also energy, re. Sovcomflot, SCF Baltica, passage earlier in August) in the normally disadvantaged remote regions of Northern Scandinavia and the Kola Peninsula (even North West Europe) a freight advantage to the fast growing markets in the Far East during a period of the year of between 2-4 months (August/September, October end July and beginning November this year — i.e. close to 4 months).

The minimum ice extent for the year will probably occur in the next two weeks.

At the end of August, ice extent had fallen to the fourth lowest in the satellite record, behind the seasonal minima recorded for 2007, 2008, and 2009. On September 3, ice extent fell below the seasonal minimum for 2009 to claim third lowest on record.

At Climate Progress, Joseph Romm reports that a major analysis, titled “History of sea ice in the Arctic”, finds that there is less ice covering the Arctic today than at any time in recent geologic history.

This is from the abstract:

[E]pisodes of considerably reduced sea ice or even seasonally ice-free conditions occurred during warmer periods linked to orbital variations. The last low-ice event related to orbital forcing (high insolation) was in the early Holocene, after which the northern high latitudes cooled overall, with some superimposed shorter-term (multidecadal to millennial-scale) and lower-magnitude variability. The current reduction in Arctic ice cover started in the late 19th century, consistent with the rapidly warming climate, and became very pronounced over the last three decades. This ice loss appears to be unmatched over at least the last few thousand years and unexplainable by any of the known natural variabilities.

In the past, the Arctic thawed because of changes in Earth’s orbit. This time, it’s due to human emissions.

Romm quotes lead author Leonid Polyak’s response to the question, when was the last time the Arctic was ice free?

The paleo data we have so far is very scant, so we can’t know for sure when the Arctic was ice free in the summer last time. To be conservative, the closest candidate is the early Holocene (roughly ~10 kyr ago), when the insolation in the Arctic was high due to the beneficial orbital configuration; however, the more data I see, the stronger is my impression that there was not that little ice at that time. The next best (actually, better) candidate is the Last Interglacial, about 125kyr ago, again due to orbitally-driven high insolation: the ice was likely very low, but we can’t say whether it was completely ice free in summer or not. There are also a few other major interglacials, which may have had a similar picture, in particular Marine Isotopic Stage 11, about 450 kyr ago. In any case we are talking about very rare events controlled by a forcing very different from today. If none of those intervals was really ice free, then a million year assessment would be correct.

External forcings – primarily orbital in the past and primarily greenhouse gases now – are further boosted by Arctic amplification, primarily positive feedbacks from the retreat of ice and snow. The Arctic warming threatens to set off a cascade of effects, including speeding up the melting of the Greenland ice sheet, accelerating the rise in sea levels; and even more serious, melting of the permafrost. Release of even a fraction of the methane stored in the permafrost (the East Siberian Arctic Shelf, for example) could trigger abrupt and catastrophic climate warming.

The evidence is undeniable: human-caused greenhouse gas emissions are overwhelming the system.

While itself a consequence of climate change, the shrinking Arctic ice cap is contributing to a positive feedback loop in which global warming and loss of ice reinforce each other. White sea ice reflects most of the incoming sunlight back into space. But when the ice melts, more heat is absorbed by the darker water, which in turn heats the atmosphere above it.

An APF story about the study quotes study co-author James Screen:

It was previously thought that loss of sea ice could cause further warming. Now we have confirmation this is already happening.

The findings show that the main driver of  “polar amplification” – warming in excess of the global average – is shrinking ice cover, rather than increased cloudiness or changes in ocean and atmospheric circulation.  The study’s findings also suggest that current forecasts underestimate the degree to which the polar region could heat up in the future.

A new report from the U.S. Environmental Protection Agency titled Climate Change Indicators in the U.S. states the extent of Arctic sea ice in 2009 was 24% below the 1979 to 2000 historical average. The area covered by ice is typically smallest in September, after the summer melting season. September 2007 had the least ice of any year on record, followed by 2008 and 2009.

The National Snow and Ice Data Center reports Arctic sea ice running only a bit below the 1979-2000 average – so far.

But the ice is thin, and it’s still early.

Here’s the abstract of the Screen  & Ian Simmonds study, published this week in the journal Nature:

The rise in Arctic near-surface air temperatures has been almost twice as large as the global average in recent decades — a feature known as ‘Arctic amplification’. Increased concentrations of atmospheric greenhouse gases have driven Arctic and global average warming; however, the underlying causes of Arctic amplification remain uncertain. The roles of reductions in snow and sea ice cover and changes in atmospheric and oceanic circulation cloud cover and water vapour are still matters of debate. A better understanding of the processes responsible for the recent amplified warming is essential for assessing the likelihood, and impacts, of future rapid Arctic warming and sea ice loss. Here we show that the Arctic warming is strongest at the surface during most of the year and is primarily consistent with reductions in sea ice cover. Changes in cloud cover, in contrast, have not contributed strongly to recent warming. Increases in atmospheric water vapour content, partly in response to reduced sea ice cover, may have enhanced warming in the lower part of the atmosphere during summer and early autumn. We conclude that diminishing sea ice has had a leading role in recent Arctic temperature amplification. The findings reinforce suggestions that strong positive ice–temperature feedbacks have emerged in the Arctic increasing the chances of further rapid warming and sea ice loss, and will probably affect polar ecosystems, ice-sheet mass balance and human activities in the Arctic.