The National Snow and Ice Data Center (NSIDC) reports the Arctic sea ice melt season got off to a slow start this year, but ice extent is now plummeting.

Arctic sea ice extent declined slowly through the first three weeks of April, compared to recent years. The slow decline through March and the first few weeks of April meant that by mid-April, ice extent was at near-average levels. However, much of the extensive ice cover is thin ice that will melt quickly once temperatures rise in the Arctic. Over the past week, extent has started to fall sharply.

NSIDC says the relatively high ice extent will have little influence on how much ice melts this summer, explaining that much of the ice cover is recently formed thin ice that will melt out quickly and that sea ice extent in spring does not tell us much about ice extent the following summer. More important to the summer melt is the thickness of the ice cover, and summer weather.

A new study published in Geophysical Research Letters concludes the only physically plausible link with the Arctic sea-ice retreat observed in recent years is the anthropogenic increase in greenhouse gas concentrations:

The most likely explanation for the linear trend during the satellite era from 1979 onwards is the almost linear increase in CO2 concentration during that period.

Quelle surprise: a new study finds that economic growth causes global warming.

The study, Climate change and the world economy: short-run determinants of atmospheric CO2, is published in the on-line journal Environmental Science & Policy. Unfortunately, it’s behind a paywall. The conclusion, excepted below, describes the study’s major finding:

The major conclusion of our study is that the annual growth of atmospheric CO2 levels is strongly dependent on the absolute growth of the world economy, so that the annual absolute increase of WGDP is a key variable to capture the annual increase in atmospheric CO2. * * * Our study provides substantive evidence that in the short run, world economic activity is a major determinant of rising CO₂ concentrations (we also show that estimated CO₂ emissions closely follow the oscillations of the world economy). For each trillion that WGDP deviates from trend, CO₂ atmospheric levels deviate from trend, in the same direction, about half a part per million. These findings are important because they reduce the uncertainty in the links of the causal chain implied in climate changing, and allow for quantitative estimates of the required levels of “human activity” that would reduce CO₂ concentrations if business-as-usual conditions are maintained.

Co-author Tapia Granados, researcher at the University of Michigan, says (with a scientist’s usual hedging) what nobody is willing to hear : economic contraction will be needed to reduce atmospheric levels of CO₂. If we want to save Earth’s climate, we’ll have to disavow economic growth and instead embrace la décroissance économique.

Environmentalists made a fatal miscalculation from the get-go in failing to challenge the ideology of growth. Rachel Carson kicked off the environmental movement 50 years ago in 1962, with the publishing of Silent Spring. Carson intimated that the project of progress and growth was fatally infected with hubris. Carson showed that the consequences might be unknowable and awful – awful not only in the sense of “filling with terror and dread” but also of “inspiring awe, filling with profound reverence” as Nature took her revenge. Silent Spring touched deep emotional chords, evoking an archaic world where transgressing inviolable boundaries evoked implacable retribution from forces beyond the control of humans.

But in their minds, environmentalists as well as politicians and economists had left the ancient world and old gods behind. Environmentalists joined in believing that Nature could be negotiated with and appeased if not conquered and subjugated. Scientist and environmentalist David Suzuki points to the movement’s fundamental miscalculation:

Environmentalism has failed. Over the past 50 years, environmentalists have succeeded in raising awareness, changing logging practices, stopping mega-dams and offshore drilling, and reducing greenhouse gas emissions. But we were so focused on battling opponents and seeking public support that we failed to realize these battles reflect fundamentally different ways of seeing our place in the world. And it is our deep underlying worldview that determines the way we treat our surroundings.

The big mistake was in seeing the environment as separate from and even subordinate to the economy.

[E]nvironmental protection came to be seen as an impediment to economic growth. * * *

Now the human economy has become a force that is altering the physical, chemical, and biological properties of the planet on a geological scale, destroying the very ground of our being.

In creating dedicated departments, we made the environment another special interest, like education, health, and agriculture. The environment subsumes every aspect of our activities, but we failed to make the point that our lives, health, and livelihoods absolutely depend on the biosphere—air, water, soil, sunlight, and biodiversity. Without them, we sicken and die. This perspective is reflected in spiritual practices that understand that everything is interconnected, as well as traditional societies that revere “Mother Earth” as the source of all that matters in life.

It was a mistake from the beginning in failing to advocate for and defend the land and the environment as a spiritual practice. It was a mistake to buy into the growth paradigm, thinking environmentalism would be easier to sell if it could be portrayed as accommodating and even enhancing economic growth. By failing to stand up for the fundamental reality that we are part of and dependent on the web of life that keeps the planet habitable, the battle was lost without ever being engaged.

Similarly in Oregon, land use advocates committed a fatal error at the very beginning. Upon taking office in 1967, Republican Governor Tom McCall had the state’s quarterly economic development publication renamed from “Growth” to “Quality” (and later, to “Progress). In 1971, in an interview by Terry Drinkwater before a national audience on the CBS Evening News, McCall pleaded for people not to move to Oregon:

Come visit us again and again. This is a state of excitement. But, for Heaven’s sake, don’t come here to live.

In selling and defending new land use regulations,  McCall railed against “grasping wastrels of the land” and and “local officials who cater to developers and exploiters”. But even McCall could not bring himself to reject the economic growth paradigm, attacking only “unlimited and unregulated” growth and calling for “healthy, imaginative, nonpolluting industry”. When Senate Bill 100 emerged from the sausage factory of the legislature, the most visionary piece – “areas of critical state concern” – had been dropped from the bill; environmentalists and a vision as the land as a value in itself just weren’t that important. The bill passed only because powerful economic interests – the agriculture industry and the timber industry – were bought off with a huge property tax break, farm and forest special assessment. Deals were made with other economic interests as well, including homebuilders and industry.

In the early 2000s, Oregon’s planning program faced a moral challenge as being unfair to property owners, depriving them of their economic rights. The program’s supporters early reliance on economics as its justification left them disarmed in the face of a moral challenge. Their response to the proponents’ “fairness” argument was a feeble, “it’s too expensive”. Their response, when Measure 37 passed, was to save the program by destroying it. Land use “advocates” promulgated and spend millions to pass Measure 49, which enshrined “property rights” as the heart and soul of land use in Oregon. “Fairness” supplanted the admittedly limited goal of “preservation of a maximum amount of the limited supply of agricultural land . . . necessary to the conservation of the state’s economic resources” – a goal that itself embodied the fatal flaw that would eventually lead to the planning program’s demise. Any regulation that hits a property owner in the pocketbook is now and forever anathema.

In saving its land use planning program, Oregon land use proponents betrayed and sacrificed the very land the program was supposed to nurture and protect, too timid to even engage in its defense. As with environmentalism generally, the battle was surrendered without being fought.

The Arctic sea ice melt season is off to an extremely slow start, with extent and area numbers approaching the long-term averages.

Will the trend lines soon start falling of a cliff? Well, the Polar Science Center at the University of Washington reports that ice volume is still at or near record lows for this time of the year. Ice volume for March 2012 was 20,800 km³, the same as last year but 35% lower than the maximum in 1979, 24% below the mean, and 1.7 standard deviations from the trend.

Most of the older, thicker ice has disappeared from the Arctic.

This March, first-year ice made up 75% of the Arctic sea ice cover. Thicker multi-year ice used to make up around a quarter of the Arctic sea ice cover. Now it constitutes only 2%. This thin, young ice is susceptible to melting. The areas in purple on the map above can be expected to disappear quickly once the melting season gets underway in earnest.

Melting sea ice is apparently initiating a previously unknown feedback effect. In a study published in Nature Geoscience, researchers report that significant amounts of methane are released from the ocean into the atmosphere through cracks in the melting sea ice.  Previously, large methane plumes have been observed emanating from the seabed in the relatively shallow sea off the northern coast of Siberia, but the latest findings come far away from land in the deep, open ocean where the surface has in the past been capped by ice. The researchers conclude:

We suggest that the surface waters of the Arctic Ocean represent a potentially important source of methane, which could prove sensitive to changes in sea ice cover. The association with sea ice makes this methane source likely to be sensitive to changing Arctic ice cover and dynamics, providing an unrecognised feedback process in the global atmosphere-climate system.

The researchers estimate open ocean emissions are comparable to emissions seen on the Siberian shelf.

Methane is about 70 times more potent as a greenhouse gas than carbon dioxide when it comes to trapping heat. Because methane is broken down rather quickly in the atmosphere, it is about 20 times more powerful averaged over a 100-year period.

The Willamette Speedway is a 1/3 mile clay dirt track in Lebanon, Oregon, in the county but right on the city boundary. It was first established in the 1960s before zoning, when Oregon was still the wild west and anything went. In that era the car culture ruled supreme. The interstate highway system was nearing completion. The U.S. still reigned as the world’s largest producer of oil – and U.S. oil production was still rising. The words “global warming” had not yet been uttered, except perhaps by a few prescient pairs of lips.

Things were soon to change. Oil production in the U.S. peaked in 1971. Linn County passed its first zoning ordinance in 1972, and in 1973 Oregon passed Senate Bill 100 and began to implement this country’s first statewide land use planning program.

In 1981, James Hansen published his first global temperature projection . . .

. . . a projection that has so far proved to be pretty darn good.

Since 2004 world oil production has remained within 5% of its peak despite historically high prices.

Now, almost 50 years later, Willamette Speedway wants to expand. As a nonconforming use, that should be pretty tough. A nonconforming use can be altered only if the alteration would have “no greater adverse impact to the neighborhood”.

The noise from the racetrack is bad enough. The roar of engines and the blaring of loudspeakers can be heard a dozen or more miles away, every weekend from late March to early October.

But the issues involve more than noise, which disturbs the tranquilly throughout the city and the countryside and must be insufferable for those who live close by. More than light from the towers lining the track. More than traffic on neighborhood streets.

The big issue is the continued celebration of the car culture. Driving as fast as you can around in a circle, going nowhere, burning precious fossil fuels, spewing greenhouse gas emissions in the process. Oil markets are global. The atmosphere doesn’t respect borders. Our neighborhood is bigger than Lebanon, bigger than Linn County. Our neighborhood is the world.

The time for indulgence of such foolishness is long past. Continued indulgence of such destructive profligacy is unconscionable. Like Christine, the car culture is a killer. And like Christine, that killer is refusing to die.

A recent post noted that Arctic warming is already affecting Earth’s weather. The analysis revealed two major factors contributing to the unusual Norther Hemisphere weather events in recent winters: changes in atmospheric circulation and changes in atmospheric water vapor content. Both are linked to diminishing Arctic sea ice.

The study, titled “Impact of declining Arctic sea ice on winter snowfall”, is published in the online early edition of the journal Proceedings of the National Academy of Sciences.

A press release quotes co-author Judith Curry:

Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation. The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.

The Georgia Tech study found that Arctic sea ice loss had in recent years caused a 20 – 60% weakening of the west-to-east belt of winds circling the pole, producing broader meanders in the jet stream that allows it to get “stuck” in place 20 – 60% more often. Co-author Jiping Liue explains:

We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere. These pattern changes enhance blocking patterns that favor more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States.

While the eastern parts of Canada and the U.S. experienced episodes of almost summer-like conditions this past winter, much of Europe and Asia has been blasted by unusually cold and snowy weather. The jet stream marks the boundary between cold, Arctic air to the north, and warmer subtropical air to the south, areas on both sides of the jet are subjected to extended periods of unusually warm or cold weather during a blocking episode. A blocking pattern early this year brought exceptionally cold and snowy conditions to much of Europe, which lay on the cold side of an elongated loop of the jet stream that got stuck in place. Conversely, most of North America and northern Siberia saw unusually warm temperatures during this period, since they were on the warm side of the jet stream. The cold air spilling out of the Arctic during this past winter was confined to Europe – unlike the previous two winters, which were unusually cold and snowy in the Eastern U.S.

This chart from Jeff Master’s Wunderblog shows what such a “blocking pattern” looked like in the U.S. this March, resulting in record warm temperatures in the midwest and on the east coast while the west coast was being hit with a rare late-season episode of cold and snow.

UPDATE: here’s yet another study linking Arctic amplification to extreme weather in mid-latitudes. The jet stream, the study says, is becoming “wavier,” with steeper troughs and higher ridges. Weather systems are progressing more slowly, raising the chances for long-duration extreme events, like droughts, floods, and heat waves. These effects are particularly evident in autumn and winter consistent with sea-ice loss. Key points:

• Enhanced Arctic warming reduces poleward temperature gradient
• Weaker gradient affects waves in upper-level flow in two observable ways
• Both effects slow weather patterns, favoring extreme weather

Jeff Masters at Wunderblog posts these satellite images showing the dramatic reduction in Arctic sea ice over the last three decades.

Arctic sea ice in September 2007 reached its lowest extent on record, approximately 40% lower than when satellite records began in 1979. Sea ice loss in 2011 was virtually tied with the ice loss in 2007, despite weather conditions that were not as unusual in the Arctic.

Masters points out the area of lost ice coverage is equal to about 44% of the contiguous U.S., or 71% of the non-Russian portion of Europe.

The National Snow and Ice Data Center says the Arctic sea ice melt season has finally begun:

On March 18, 2012, Arctic sea ice extent reached its annual maximum extent, marking the beginning of the melt season for Northern Hemisphere sea ice. This year’s maximum extent was the ninth lowest in the satellite record.

Sea ice appeared to have reached its maximum extent earlier in the month on March 6 – but an unexpected change in Arctic weather lead to a late-season surge.

The maximum this year was very late compared to recent years, occurring 12 days later than the 1979 to 2000 average date of March 6.

• March 6th 2005: 13.46
• March 11th 2006: 13.36
• February 26th 2007: 13.32
• March 11th 2008: 13.89
• March 2nd 2009: 13.85
• March 7th 2010: 13.81
• March 8th 2011: 13.14
• March 20th 2012: 13.70

This year’s maximum ice extent was 15.24 million square kilometers (5.88 million square miles), 614,000 square kilometers (237,000 square miles) below the 1979 to 2000 average of 15.86 million square kilometers (6.12 million square miles). This year’s maximum was the ninth lowest in the satellite record. Last year (2011) was the lowest maximum on record at 14.64 million square kilometers (5.65 million square miles). Including this year, the nine years from 2004 to 2012 are the nine lowest maximums in the satellite record.

Sea ice extent in February and March tends to be quite variable, because ice near the edge is thin and often quite dispersed. The thin ice is highly sensitive to weather, moving or melting quickly in response to changing winds and temperatures, and it often oscillates near the maximum extent for several days or weeks, as it has done this year. NSIDC’s call includes this caveat:

As of March 23, ice extent has declined for five days. However, there is still a chance that the ice extent could expand again.

Why should we care about what’s happening in the Arctic? Because the Arctic is the “canary in the coal mine”, warming faster than anyplace else on Earth.

The warming Arctic is already affecting Earth’s weather. The erratic weather and extreme weather events seen over last few years are merely a foretaste of what’s in store for the future. Jennifer A. Francis, a Rutgers University climate researcher, is quoted in the New York Times:

The question really is not whether the loss of the sea ice can be affecting the atmospheric circulation on a large scale. The question is, how can it not be, and what are the mechanisms?

Climate mechanisms in the Arctic are a major driver of weather in the northern hemisphere, including not only “über-extreme” weather events but also the weird and unpredictable weather affecting crops and livelihoods at home, like here in Oregon. What happens in the Arctic directly impacts us in our daily lives.

Ice extent usually reaches its annual maximum sometime in late February or March, but the exact date varies widely from year to year.

The National Snow and Ice Data Center (NSIDC) reports that sea ice extent in February (as in January) was low on the Atlantic side of the Arctic, but unusually high on the Pacific side of the Arctic, remaining lower than average overall. At the end of the month, ice extent rose sharply, as winds changed and started spreading out the ice cover.

The University of Washington’s Polar Science Center latest updated graph shows ice volume is now slightly lower than last year.

Neven at Arctic Sea Ice Blog reports that this year’s multi-year ice cover as of January 1 was just a bit higher than that of 2008, which was extremely low due to the preceding record melting season of 2007.

It’s unusually “not cold” in much of the Arctic . . .

. . .  with the notable exception of the Beaufort, Chukchi, and Bering Seas – which is consistent with the expanded ice extent on the Pacific side of the Arctic.

We will soon begin to see the 2012 melting season unfold, as it is about to start (if it hasn’t already). [Update 3/14: Neven at Arctic Sea Ice Blog has called the maximum as of March 6, 2012. The 2012 Arctic sea ice melt season is officially underway.]

One more thought: notice the anomalously warm temperatures around Greenland, especially on the eastern side. A new study by scientists from the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid concludes the Greenland ice sheet is more vulnerable to global warming than previously thought. The best estimate of the temperature threshold for melting the ice sheet completely is 1.6 degrees above pre-industrial levels, with a range of 0.8 to 3.2 degrees Celsius. And 0.8 degrees global warming has already been observed.

Previous research estimated the threshold in global temperature increase for melting the Greenland ice sheet was 3.1 degrees, with a range of 1.9 to 5.1 degrees. The new study’s best estimate is about half that.

Team-leader Andrey Ganopolski of PIK explains that the Greenland ice sheet could hit a “tipping point” beyond which recovery would become impossible:

Our study shows that under certain conditions the melting of the Greenland ice sheet becomes irreversible. This supports the notion that the ice sheet is a tipping element in the Earth system. If the global temperature significantly overshoots the threshold for a long time, the ice will continue melting and not regrow – even if the climate would, after many thousand years, return to its preindustrial state.

The vulnerability of the Greenland ice sheet arises because of feedbacks between the climate and the ice sheet. The ice sheet is over 3000 meters thick and thus elevated into cooler altitudes. When it melts its surface comes down to lower altitudes with higher temperatures, which accelerates the melting. Also, the ice reflects a large part of solar radiation back into space. When the area covered by ice decreases, more radiation is absorbed and this adds to regional warming.

A business-as-usual scenario of greenhouse-gas emissions could lead to 8 degrees Celsius of global warming. This would result in one fifth of the ice sheet melting within 500 years and a complete loss in 2000 years. Alexander Robinson, lead-author of the study, notes:

[C]ompared to what has happened in our planet’s history, it is fast. And we might already be approaching the critical threshold.

Melting of the current Greenland ice sheet would result in a sea-level rise of about 6.5 meters.

This morning at dawn, the sky was filled horizon to horizon with flights of geese, constantly calling as they headed north. Flight after flight passed over the farm, the surrounding woods alive with the chatter of birds. The cacophony was almost enough to drown out the background aspiration of  motor vehicles, inescapable even out here in the countryside, far from any town or highway.

In my darker moments, I am filled with foreboding. Oil and other fossil fuels, humans could and will learn once again to live without. And even thrive, as humans did for tens of thousands of years – although our numbers might not be so great. Perhaps a blessing, as the world would be replenished with other species. But consider: what if, in the last spasms of the fossil fuel age, humans were to destroy the very ground of their being, erasing any chance of transitioning to a more gentle and hopeful future?

Humans have already set in motion forces that are profoundly changing Earth, most likely into an Earth we will no longer find familiar and amenable.

A new study in the journal Science finds only one period in the last 300 million years when the oceans acidified as fast as today: the Paleocene-Eocene Thermal Maximum, or PETM. Says lead author Bärbel Hönisch:

What we’re doing today really stands out in the geologic record. We know that life during past ocean acidification events was not wiped out – new species evolved to replace those that died off. But if industrial carbon emissions continue at the current pace, we may lose organisms we care about – coral reefs, oysters, salmon.

In his comments on the study, Joseph Romm at Climate Progress notes humans are putting marine life at risk in a frighteningly unique way:

[T]he current rate of CO₂ release stands out as capable of driving a combination and magnitude of ocean geochemical changes potentially unparalleled in at least the last ~300 My of Earth history, raising the possibility that we are entering an unknown territory of marine ecosystem change.

Old species, new species – Earth doesn’t care. But we might. Especially if one of those species is us.

Global temperatures are rising, with Arctic temperatures rising the most. Arctic ice is disappearing, with the oldest and thickest Arctic ice vanishing faster than younger, thinner ice. Sea ice loss is affecting the large-scale atmospheric circulation, which leads to weird weather patterns and extreme weather events in the Northern Hemisphere: longer-duration cold spells, snow events, heat waves, flooding events, and drought conditions.

Earth takes several decades to respond to increased CO2 because of the thermal inertia of the oceans. Consequently, the effects we’re seeing today result from what we thoughtlessly dumped into the air 25 to 50 years ago. And emissions have grown enormously since then. While global crude oil production may have finally plateaued, crude production increased about 25% since 1980. Global natural gas production doubled over that period, while global coal production almost doubled. Climate impacts from the huge amounts of CO2 emitted in the last three or four decades, although yet unfelt, are already locked in.

Emissions are now beyond the control of the U.S. and other western nations. Asia-Pacific coal output has doubled, and doubled again (a 400 percent increase) since 1980. China’s coal consumption is now four times that of the U.S., and China alone is now responsible for about half of the world’s coal consumption.

Global emissions have never been higher than now, and prospects for voluntarily doing anything to lower them are nil. In another thirty or forty years, humans will begin to reap the consequences. Unfortunately, other living creatures will suffer the consequences, too. Resource limits and economic contraction offer the only hope for keeping the consequences of climate change to merely “catastrophic” levels.

One of the reasons we choose to live in the Pacific Northwest is because the region is predicted to suffer relatively less from climate change. But even if those “rosy” scenarios prove correct, how much faith can we place in the continued ecological integrity and productivity of our refuge? Will geese continue to fly north to breed in the spring? Will salmon continue to spawn in our streams? Will the mighty Douglas-fir continue to grow thick in our mountains? Will the rains continue to fall, greening the grass and nurturing our crops? Will the summer warmth continue to ripen our grapes and our tomatoes? After the last couple of summers, who can be sure?

For our lives it probably doesn’t matter, as the more fearsome consequences of humanity’s perfidity won’t have time to become manifest before the end of our time on Earth. But we shudder for those who will follow.

Pray for collapse. Plan for collapse. Work for collapse. Collapse is humanity’s only hope.

The National Snow and Ice Data Center reports Arctic sea ice extent in January 2012 averaged 13.73 million square kilometers (5.30 million square miles) – the fourth-lowest January ice extent in the 1979 to 2012 satellite data record.

Before 2005 average January ice extent had never been lower than 14 million square kilometers (5.41 million square miles). January ice extent has now fallen below that mark six out of the last seven years.

Large areas of the Barents Sea and the adjoining Kara Sea that are normally locked in ice by now are still open. Sea ice concentration maps posted by Neven at Arctic Sea Ice Blog show how unusual 2012 is:

University of Bremen sea ice concentration maps, cropped

The University of Washington’s Polar Science Center reports Arctic sea ice volume for January 2012 was 16,200 km³ , slightly larger than last year (15,800 km³) but 41% lower than the satellite record era maximum in 1979, 28% below the mean and 1.4 standard deviations from the trend.

Total Arctic sea ice volume from PIOMAS.
Shaded areas indicate one and two standard deviations from the mean.

The melting season starts in about six weeks.

It’s not just sea ice that has been diminishing. In a new study, researchers using satellite measurements calculate that the world’s glaciers and ice caps lost about 148 billion tons, or about 39 cubic miles of ice annually from 2003 to 2010. This total does not count the mass from individual glacier and ice caps on the fringes of the Greenland and Antarctic ice sheets, which could add up to an additional 80 billion tons.  The researcher’s data shows total sea level rise from all land-based ice on Earth, including Greenland and Antarctica, was roughly 1.5 millimeters per year from 2003 to 2010, cumulatively about 12 millimeters. The sea rise amount includes the expansion of water due to warming. Thermal expansion of water is the second major contributor to sea level rise, roughly equal to melting ice.

The Greenland and Antarctic ice sheets are losing mass at an accelerating pace. A recent study sponsored by NASA concluded that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15 centimeters (5.9 inches) by 2050. When this is added to the predicted sea level contribution of 8 centimeters (3.1 inches) from glacial ice caps and 9 centimeters (3.5 inches) from ocean thermal expansion, total sea level rise by 2050 could reach 32 centimeters (12.6 inches).

Arctic temperatures set a new record high in 2011, beating the record set just the previous year in 2010.

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.