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.

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 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.

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.

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.

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.

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).

The Independent interviewed Igor Semiletov, of the Far Eastern branch of the Russian Academy of Sciences, who said that he has never before witnessed the scale and force of the methane being released from beneath the Arctic seabed:

Earlier we found torch-like structures like this but they were only tens of metres in diameter. This is the first time that we’ve found continuous, powerful and impressive seeping structures, more than 1,000 metres in diameter. It’s amazing. I was most impressed by the sheer scale and high density of the plumes. Over a relatively small area we found more than 100, but over a wider area there should be thousands of them.

In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed. We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale – I think on a scale not seen before. Some plumes were a kilometre or more wide and the emissions went directly into the atmosphere – the concentration was a hundred times higher than normal.

Scientists have calculated there is about 1.7 trillion tons of carbon in soils of the northern regions, about two and a half times the amount of carbon in the atmosphere. Much of that carbon leaks out in the form of methane rather than carbon dioxide. 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.

Here’s a dramatic video of methane burning from a frozen lake in Alaska.

Some extinction events in Earth’s past have been linked to warming causing methane to be released, leading to even more warming and more methane release in a deadly feedback loop. Once the carbon locked in the permafrost begins to thaw and be released, the process could be impossible to stop.

With the disappearance of the Arctic sea-ice in summer and rapidly rising temperatures across the entire region, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change. Semiletov’s research confirms the Siberian permafrost is already melting.

Semiletov released his findings for the first time last week at the American Geophysical Union meeting in San Francisco.

Are humans really stupid enough to cause their own extinction? Sadly, I’d know where I’d place my bet.

The brief pause in the growth of emissions during the recession is over, at least for now. Emissions grew at a rate of ~3% yearly during the last decade. The growth rate in the 1990s was ~1% per year.

The analysis showed developing countries, including China and India, have surpassed the wealthy countries in greenhouse emissions. In 2010, developing countries were responsible for 57% of global emissions. But don’t think that rich countries are off the hook. The fast rise in developing countries has been caused to a large extent by the outsourcing of energy-intensive manufacturing industries. The rich countries have exported some of their emissions while continuing to consume the imported goods.

Meanwhile, the climate talks in Durban are going nowhere. The latest “earth-shaking” news is that China may agree to legally binding emissions reductions – but no earlier than 2020, and only if Kyoto is extended, and only if rich nations kick in $100 billion annually to a nonexistent mitigation fund. The U.S. is saying it isn’t interested, preferring “bilateral agreements”.

The clock is ticking. If the rise in greenhouse gas emissions is not reversed quickly and substantially, by 2020 it will be game over for saving Earth’s human-friendly climate.

Despite a relatively cool, La Niña influenced 2011, the 10-year running average for the period 2002-2011 ties 2001-2010 as the warmest 10-year period on record.

Even before the climate talks in Durban began on Monday, participating nations were conceding that the chances of reaching any meaningful agreement were zilch. Expectations are low: the best to be hoped for is an agreement to begin negotiations on a global deal that can be implemented by 2020, along with making “some progress” on establishing “financing mechanisms” to help developing nations deal with the impacts of global warming. With western economies in the process of imploding, any agreement on money transfers – no matter how modest – may now be out of reach.

Two days into the talks, actions by Canada threaten to torpedo what remains of the global climate process. A rumor surfaced that the government of Conservative Prime Minister Stephen Harper plans to formally withdraw from the Kyoto Protocol on curbing climate change before the end of 2011. Canadian Environment Minister Peter Kent, commenting on but refusing to confirm the report, referred to the Kyoto agreement as “in the past” and stated that opting into the treaty was “one of the biggest blunders” made by the previous Liberal government.

The “rumor”—coming so early in the climate negotiations—is likely to render the low-held chances for a treaty breakthrough at the Durban talks even more remote.

Time is fast running out if catastrophic climate change is to be averted. Just recently Fatih Birol, chief economist at the International Energy Agency (IEA) and one of the world’s foremost authorities on climate economics, warned:

If we do not have an international agreement whose effect is put in place by 2017, then the door to holding temperatures below 2 ° C will be closed forever.

The thinking that a 2 ° C rise would be “safe” is optimistic, as no climate model currently incorporates the amplifying feedback from methane released by a defrosting tundra. A new study published in Nature titled Climate change: High risk of permafrost thaw finds the permafrost can be expected to releases up to 380 billion tonnes of CO₂ equivalent by 2100:

Arctic temperatures are rising fast, and permafrost is thawing . . . . Our collective estimate is that carbon will be released more quickly than models suggest, and at levels that are cause for serious concern.

We calculate that permafrost thaw will release the same order of magnitude of carbon as deforestation if current rates of deforestation continue. But because these emissions include significant quantities of methane, the overall effect on climate could be 2.5 times larger.

The new study only looked at the land-based permafrost.  A study published last year warned release of even a fraction of the methane stored offshore in the Eastern Siberian ice shelf could trigger abrupt climate warming.

The new study finds:

Across all the warming scenarios, we project that most of the released carbon will be in the form of CO₂, with only about 2.7% in the form of CH₄. However, because CH₄ has a higher global-warming potential, almost half the effect of future permafrost-zone carbon emissions on climate forcing is likely to be from CH₄. That is roughly consistent with the tens of billions of tonnes of CH₄ thought to have come from oxygen-limited environments in northern ecosystems after the end of the last glacial period.

Edward Schuur, lead author of the study in Nature, pleads that we must address the source of emissions from humans if we are to have any chance of keeping Arctic carbon frozen in permafrost rather than going into the atmosphere.

Given what’s going on in Durban – where the best outcome that can be expected is for the rich nations to agree to throw a hundred billion dollars or so as a sop to the poorer nations, rather than actually doing anything to slash emissions – the chances of that coming to pass are approaching zero.