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Greenland Melt Extent Breaks 50% on July 4; 2 Standard Deviation Line Shattered Yet Again

These days — in the age of the fossil-fueled hothouse — it’s never good news when a high pressure system forms over Greenland during Summer.

Human dumping of carbon into the atmosphere has forced warming over the last remaining great Northern Hemisphere ice sheet at a rate of about 0.5 degrees Celsius each decade. A constant rain of soot from human industry and from increasingly prevalent and intense Arctic wildfires has painted the ice sheet dark, lowering its ability to reflect 24 hours of incoming radiation from the Summer sun. And the result is that each Summer, when the skies clear and high pressure systems form over the ailing Greenland ice, you end up getting these huge surface melt spikes.

Greenland smoke

(Smoke from record Alaskan and Canadian wildfire outbreaks traverses Greenland and enters the North Atlantic on July 2 of 2015. Arctic wildfires are intensified by human-caused warming both through the mechanism of added heat and through the reintroduction of long sequestered carbon fuels through permafrost melt which aids in the initiation, intensification and extension of Arctic wildfire burn periods. In essence soil carbon in the form of thawed permafrost and related methane adds to boreal forest, tundra and bog as burn risks. Soot from these fires can then precipitates onto land and sea ice, reducing its ability to reflect the 24 hour Summer Arctic sun. Image source: LANCE MODIS.)

Generally a big melt spike can be defined as anything greater than 35 percent of Greenland ice surface area. And we’ve had quite a few of these abnormal events in recent years. The worst of which happened in mid Summer of 2012.

During late June and early July of that year, an extreme high amplitude Jet Stream wave generated very warm surface temperatures over the Greenland Ice Sheet. A very warm fog settled over the ice, eating away at it. By July 8th, more than 90 percent of the surface was melting — an event that hasn’t happened in Greenland for more than 100 years. June, July and August of 2013 and 2014 saw similar, though somewhat less intense, Greenland melt spikes. During those years the ice sheet experienced multiple days in which melt covered between 35 and 45 percent of its surface. And though these instances were not as intense as the unprecedented 2012 melting, they did traverse well beyond the 1981 to 2010 average line (an average that itself includes a rapid warming trend) to, in cases, exceed the upper 2 standard deviation margin.

Melting on Greenland surface 2014

(Record Greenland surface melt during 2012 compared to still strong surface melt years of 2013 and 2014. Image source: NSIDC.)

After record 2012 melt, surface melt for Greenland has remained abnormally high — indicating an increased likelihood that more near 100 percent surface melt summer days may not be too far off in the future. The post 2012 environment for Greenland has thus been a period of continued and heightened surface melt. One that appears to be in the process of building up to another big pulse.

50 Percent Melt Threshold Exceeded During July of 2015

The summer of 2015 marks a continuation and intensification of this ominous surface melt trend. After getting off to about an average melt start during April and May, June saw surface warmth build over the Greenland Ice Sheet with melt extents jumping to between 30 and 40 percent of surface area by mid-to-late month. Further warming coincided with massive Alaskan and Canadian wildfires injecting soot plumes into regional airspace and the building of a substantial high pressure ridge over Greenland. These factors helped enable further atmospheric and ice warming — shoving surface melt above the 50 percent line by July 4th.

Greenland melt extent 2015

(Major Greenland melt spike indicated on July 1-5 in the NSIDC surface melt extent graph. Image source: NSIDC.)

This puts 2015 Greenland surface melt in a range well above 2013 and 2014, with the first week of July already exceeding 2012 melt for that period.

Over the next seven days, models predict a larger warming of the overall Arctic environment even as a high pressure system and associated ridge remains entrenched across Greenland. This predicted weather pattern will tend to lock in significantly warmer than 20th Century average temperatures. That said, forecast highs do not yet indicate a substantial risk for a repeat of 2012’s near 100 percent surface melt. However, projected high temperatures do show some potential that melt percentages are likely to continue to range between 40 and 60 percent surface melt over coming days with the highest risk for melt spikes occurring on July 6th, 7th and 8th.

It is worth noting that we are now in the midst of a substantial Greenland melt spike, one that we’ll continue to monitor over coming days for further developments.

Links:

LANCE MODIS

NSIDC

Dark Snow

GFS Forecast Summary

Record Alaskan Wildfire Outbreak

Hat Tip to Wili

Hat Tip to Andy in San Diego

Hat Tip to Colorado Bob

Hat Tip to DT Lange

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New Study Finds 3-4 Meter Sea Level Rise From Antarctica May be Imminent

Ocean stratification. A condition characterized by the separation of layers of water of different temperatures and chemical make-up. A condition that has serious impacts to the geophysical nature of the worlds oceans, to the ability of oceans to support life, and to the stability of the vast glaciers of Antarctica — whose faces plunge as deep as hundreds of feet into the Southern Ocean.

In the Antarctic, today, what we see is a cold surface layer and a heating bottom layer. The cold surface layer is fed by an expanding pulse of chill, fresh water issuing from the melting glaciers of Antarctica. Over the years it has become more uniform, sequestering cold near the surface as warmth builds up in the depths below. The deeper hot layer is fed by warmer water issuing in from the tropics and heated to temperatures not seen for tens of thousands of years. This hot water bears a heavy burden of salt. So it is denser and it dives beneath the expanding fresh water layer. The insulating fresh, cold water layer prevents mixing between the bottom layer and the surface. Such mixing would cool the bottom layer. But instead the heat builds and builds and builds.

Difference in Ice mass Between now and last glacial maximum

(Antarctica — visual difference in ice mass between now [right] and last glacial maximum [left]. By mid century, atmospheric greenhouse gas concentrations driven by humans could be high enough [550 ppm CO2e+] to melt all the remaining ice upon this now-frozen continent. Image source: NASA/Goddard Space Flight Center.)

Ocean currents bring the deep, hot water in contact with the base of Antarctica’s massive glaciers. And this intensely focused heat engine goes to work to rapidly melt the ice.

It is this condition of ongoing and intense melting of the ice sheet’s bases that terminate in faces of ice cliffs, hundreds of feet high and deeply submerged in the sea, that is driving the irreversible collapse of many glaciers in Antarctica. Already, due to this irreversible fall, the entire flank of West Antarctica is under collapse — locking in at least three feet of sea level rise from this region alone going forward.

But now, a new study finds that these conditions — the same conditions we observe today — led to the release of enough glacial ice from Antarctica alone at the end of the last ice age to raise sea levels by 3-4 meters (10-13 feet) in just 1-3 centuries.

From Nature Communications:

“The reason for the layering is that global warming in parts of Antarctica is causing land-based ice to melt, adding massive amounts of freshwater to the ocean surface,” said ARC Centre of Excellence for Climate System Science researcher Prof Matthew England an author of the paper.

“At the same time as the surface is cooling, the deeper ocean is warming, which has already accelerated the decline of glaciers on Pine Island and Totten. It appears global warming is replicating conditions that, in the past, triggered significant shifts in the stability of the Antarctic ice sheet.”

The last time this happened was 14,000 years ago as the Earth slowly warmed out of the end of the last ice age. But the result was anything but gradual:

“Our model simulations provide a new mechanism that reconciles geological evidence of past global sea level rise,” said researcher UNSW ARC Future Fellow Dr Chris Fogwill.

“The results demonstrate that while Antarctic ice sheets are remote, they may play a far bigger role in driving past and importantly future sea level rise than we previously suspected.”

“The big question is whether the ice sheet will react to these changing ocean conditions as rapidly as it did 14,000 years ago,” said lead author Dr Nick Golledge, a senior research fellow at Victoria’s Antarctic Research Centre.

These are critical questions. Ones that have serious impacts for the more than 700 million people now living within 10 meters of current sea level.

Antarctic Ice Shelf Thickness Changes

(Antarctic Ice Shelf thickness changes. Note the thinning of almost all the ice shelves along the margin of Antarctica. Ice shelves anchor interior ice, keeping it from rushing out through deep channels into the Southern Ocean. Rapidly thinning ice shelves is a precursor to glaciers rushing toward the sea. Image source: Nature Pritchard et al. 2012)

To this point it is worth noting that the pace of warming 14,000 years ago was on the order of 0.05 degrees Celsius each century. The current pace of human-driven warming over the past century was 20 times faster. This century, the warming is predicted to be as much as 500 times faster (3-5 C warming by 2100). So the question may we be — will Antarctica respond as ‘slowly’ as it did at the end of the last ice age? Slow as in ice outbursts that lead to sea levels rising by as much as 14 feet during one century.

Links:

Change Antarctic Conditions Could Trigger Steep Rise in Sea Levels

Antarctic Contribution to Meltwater Pulse 1A From Reduced Southern Ocean Overturning

Weighing Change in Antarctica

It’s All About Fresh Water — Rapid Sea Level Rise Points to Glacial Melt in Antarctica

Human-Destabilized Antarctica Capable of Glacial Outbursts Contributing to Sea Level Rise of 14+ Feet Per Century

Antarctic Ice Sheet Loss Driven by Basal Melting of Ice Shelves

(Hat Tip to Colorado Bob)

 

 

 

 

 

Late June 2014: Arctic in Hot Water as Sea Ice Thins and Tundra Fires Erupt

Atmospheric warming due to human-caused climate change. It’s the general measure we’ve used to track a devastating and ongoing heat amplification due to a terrible greenhouse gas emission. But if we were to look for where the greatest amount of that heat has accumulated, it would be in the world’s oceans. For from its air-contacting surface to its depths thousands of meters below, the World Ocean has captured 93.4% of the total heat forcing humans have already unleashed. The remainder is almost evenly divided between the atmosphere, the continents, and the ice.

We rely on floats and deep-plunging sensors to keep track of total ocean heat content. But on any given day we can see well enough what is happening at the surface. And today ocean surface heat is screaming through the world’s satellite sensors. Overall global anomalies are spiking higher than +1 C above the 1979 to 2000 average. In the Equatorial Pacific, an El Nino that looks to be far stronger than the one that occurred in 2009-2010 is building, heating a massive wedge of the Eastern Equatorial Pacific to +2 to +4 C above average. And in the far north, we see extraordinary high surface water temperature departures exactly where we need them least — bordering Greenland and the remaining Arctic sea ice.

Arctic Sea surface temperature Anomaly on Jun 24

(Arctic sea surface temperature anomaly on June 24, 2014. Image source: NOAA/NWS.)

For encircling the Arctic from the West Coast of Greenland, to Iceland, to Svalbard, to the Barents and Kara Seas, to the Chukchi and on to the Beaufort we see surface water temperatures ranging from 2.25 to 4 C or more above average. And just west of Svalbard, we have water temperatures ranging in a zone exceeding a terrifying 8 C above average. When a sea surface temperature departure of 0.5 to 1 C above average is considered significant, these values represent extremes that are far outside what was once considered normal.

Melt Pressure to Ice Sheets

Such high surface water temperatures have numerous effects. The first is that adjacent submerged ice sheets, such as the calving faces of Greenland’s great glaciers plunging into the ocean, are faced with a far greater melt pressure than before. The glacial fronts in many cases expose 500 or more feet of ice directly to these much warmer waters. And on almost every side of Greenland, but especially in the west, along Baffin Bay, these great ice masses are confronting extraordinary warmth. The heating is without respite. It occurs at all hours of the day and since it is delivered by water, it is many times more energy intensive than a similar volume of equally heated air.

Widespread Sea Ice Thinning and Melt

In the sea ice edge zone, the warmth also provides added heat pressure to the vulnerable and already greatly thinned ice floes. This heating is especially apparent in areas where continental rivers disgorge their waters into the Arctic Ocean. Warmer than normal water temperatures have coincided with much warmer than normal land temperatures, particularly over tundra regions like Canada’s Northwest Territory and the Yakutia region of Russia. These warmer lands result in warmer river flows. And the hot rivers spill into an already hotter than usual Arctic Ocean.

The result, as we can see in today’s MODIS satellite shots are numerous zones of greatly thinned ice.

Beaufort Thin Ice

(Ice melt, thin ice and melt ponds in the Beaufort Sea on June 25 of 2014. Image source: LANCE MODIS.)

A Beaufort Sea confronted with warm water outflow from the Mackenzie River, sea surface temperatures in the range of +1 to +4.5 C above average, and a broad swath of above freezing air temperatures, is now starting to show major melt effects. The sea ice has already withdrawn by as much as 150 miles from a broad section of the Canadian and Alaskan coasts. The off-shore ice features numerous very large polynyas and leads. And, overall, the ice has taken on a bluish tint indicative of widespread melt pond formation.

Russian Arctic Ocean sea ice june 25

(Arctic Sea Ice over the Laptev and East Siberian Seas. Image source: LANCE MODIS.)

Meanwhile on the far side of the Arctic, effects appear to be even more widespread. Though sea surface temperature values are somewhat lower than those seen in the Beaufort, at +0.5 to +1.25 in most open water areas, the entire region is rife with 150-200 mile wide polynyas, shattered and broken floes, and thinning (blue in the satellite picture) ice covered in melt ponds. The ice in this region is so frail that even the mildest storms, featuring 15-20 mph winds, are enough to rip through and splinter previously contiguous ice. And the storms in the region this year have been quite mild, ranging from 990 to 1000 mb in strength.

Sea ice measures show current area and extent at between 3rd and 5th lowest on record. That said, observed ice response to even the mildest high and low pressure weather systems reveals a startling vulnerability with much warmer than normal sea surface temperatures surely a contributing factor.

Wildfire Eruptions From The Northwest Territory to Siberia

In net, much warmer water temperatures and retreating sea ice in the Northern Hemisphere trigger both Jet Stream erosion and increasing south to north air flow. Over the continents, where lands are far more susceptible to rapid warming, this can result in Arctic regions seeing summer time temperatures comparable to those in latitudes much further south.

Over the past week, temperatures in the upper 70s to upper 80s (Fahrenheit) covered a broad region of Canada’s Northwest Territory including Alberta and the Mackenzie Delta region along the Beaufort Sea. These temperatures, in the range of 20-25 F above average rapidly dried out the shallow topsoil zone over the frozen and thawing tundra. Such rapidly dried soil and newly liberated tundra is a volatile fuel for fires. The human-thawed tundra itself contains burnable organic material and hosts pockets of methane while the dry soil bed is suffused with tinder-like grasses and shrubs. Any ignition can set off extraordinary fires of almost unimaginable scope and intensity.

Great Slave Lake Fires NWT

(Massive fires rage near Great Slave Lake in Canada on June 24, 2014. Image source: LANCE MODIS.)

By June 24, four massive fires, each with a front ranging from 20-30 miles in breadth, raged along the shores of Great Slave Lake in Northwest Canada. Four smaller, though still significant fires also burned nearby. The fires are plainly visible as white, comet-like plumes of smoke in the satellite picture above. For reference, Great Slave Lake is more than 200 miles across at its widest point. Bottom edge of frame is about 300 miles.

To the south and east by about 250 miles lies the Fort McMurray tar sands operation. A smaller, though still intense, tundra fire raged within 20 kilometers of that sprawling site but did not yet encroach on one of the most powerful and dangerous means of carbon-to-atmosphere delivery on the planet.

On the other side of the Arctic in Siberian, Russia, the situation was, once again, more dire. There a region very vulnerable to mid summer wildfires during recent years erupted into numerous blazes belching smoke into a swirling cloud caught up in the heat dome overhead:

Lake Baikal Fires Re-Ignite

(Massive region of wildfires North of Lake Baikal, Russia. Image source: LANCE MODIS.)

These fires were sparked by temperatures that, during recent days, ranged in the 80s and even 90s. An extraordinary heat forcing for rapidly melting tundra regions that also saw far warmer than typical temperatures this past winter.

This area, about 800 miles to the north of Lake Baikal, Russia, is a region of rapidly thawing tundra that has burned again and again during recent summers. For scope, the satellite shot frame, above, is 750 miles on an edge. In the picture are about 50 fires with fronts ranging from 4-35 miles.

This spring, a broad area to the south of the current fire zone and just north of Lake Baikal saw massive fire activity prompting Russia to dispatch an army of hundreds of firefighters to the region. Such intense fire activity so early was unprecedented for Russia. But the real fire season typically peaks from mid July to August. And, in the above picture, we see what is likely the opening salvo for the summer fire season in earnest.

Smoke and soot from these massive fires are swept up in the circumpolar Jet Stream. There they are born aloft for hundreds of miles, often traveling northward to find a final resting place upon the sea ice or atop Greenland’s glaciers. This ultimate darkening of the snow further enhances glacial melt even as it completes the cycle of warmth, finishing a dance of heat that rises up from the oceans, assaults the ice, and heats the once frozen lands to erupt in flame.

 

Links:

Support the Dark Snow Project

Where is Global Warming Going?

NOAA/NWS

LANCE MODIS

When April is the New July: Siberia’s Epic Wildfires Come Far Too Early

Global Warming Pushing Canadian Wildfires to Spike

 

 

Slow Feedbacks Faster Than Expected: New Study Finds Greenland Ice Sheet Softening Up Like Hot Butter

Melt Pools

Melt pools form on Sermeq Avannarleq Glacier, in a region about 16 kilometers (10 miles) from the ice edge.

(Image source: AGU)

A new study produced by the American Geophysical Union (AGU) has found that the Greenland Ice Sheet is softening up faster than expected. The study shows that surface melt water absorbs heat and sunlight then transfers that energy into the heart of Greenland’s ice sheets resulting in sagging and more rapid movement, not just at ice sheet edges, but deep within interior glaciers.

Over the past decade, researchers found that the speed of ice motion at the edge of Greenland’s vast ice sheets had increased resulting in larger flows into the ocean. Now, ice motion deep within Greenland’s interior is also found to have sped up. The study compared the rates of ice flow during 2000 to 2001 with a period from 2005 to 2008. The results were alarming:

“Through satellite observations, we determined that an inland region of the Sermeq Avannarleq Glacier, 40 to 60 miles from the coast, is flowing about 1.5 times faster than it was about a decade ago,” said Thomas Phillips, lead author of the new paper and a research associate at the time of the study with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado, Boulder.

In 2000-2001, the inland segment was flowing at about 40 meters (130 feet) per year; in 2007-2008, that speed was closer to 60 meters (200 feet) per year.

Accelerated Ice Movement -- Greenland

Satellite observations indicate acceleration of an interior region of the southwestern Greenland Ice Sheet. In this map showing a portion of Southwest Greenland, reds and yellows mark areas where ice sheet velocity increased substantially between 2005 and 2007. CREDIT: CIRES image courtesy of AGU

At first, researchers were at a loss as to what had caused this extra ice motion. So Phillips and his team developed an advanced model to help determine how energy was being transported into the deep ice at Greenland’s heart. What they found was that melt water from the surface transfers heat energy deep into the ice sheet causing it to deform and flow faster like melting butter.

As is usual with past science on ice sheets, early models and studies concluded that it would take as long as centuries to millennia for the ice sheets to respond to surface warming. The CIRES study discovered rapid ice sheet response mere decades after the initial forcing — a blink of an eye in geological time. The AGU has accepted the CIRES study and published it for review here.

Researchers were troubled by the amount of melt water they were observing on the ice sheet’s surface. Much of this water later disappeared through great holes and chasms tunneling deep into the ice sheet. Researchers suspected this mechanism was transferring solar energy beyond the ice sheet surface and was likely affecting melt and rate of motion. The new model produced by the CIRES study provides confirmation to this observation.

Implications for Global Climate Models, Weather Stability, Speed of Sea Level Rise

Ice sheet rate of response is a key aspect of climate sensitivity. Current estimates for Earth surface temperature change assume a slow rate of ice sheet response. Rapid ice sheet response, as hinted at in this study and as observed during the past two decades, would result in far more unstable weather and climate conditions during rapid ice sheet melt (with greater swings between hot and cold in regions that may be far removed from the ice sheet) and a more rapid increase in global temperatures once compounding albedo loss occurred.

Current Equilibrium Climate Sensitivity (ECS) models account for only half of total long term warming due to an assumption that ice sheets will be slow to respond. If ice sheets respond faster, as indicated by this study and by recent observations, then the total Earth Systems Sensitivity temperature may be reached more rapidly. An Earth Systems Sensitivity for current levels of greenhouse gasses, at around 400 ppm, is probably about 3 degrees Celsius long-term. Such warming is enough to melt both Greenland and West Antarctica and probably a portion of Antarctica before Earth Systems Equilibrium is achieved. Total sea level rise in such a scenario is likely to approach as much as a 75 foot height at termination. The possibility that this may happen faster than previously expected is cause for serious concern.

Based on observations of increasing ice sheet melt and motion, I have estimated that sea level will increase by between 5 and 15 feet this century (depending on rate of greenhouse gas accumulation). This observation is faster than the IPCC case which estimates about 3 feet and James Hansen who estimates between 6 and 10 feet. My rationale for this rate of rise is based on a meta-analysis that includes the assumption that the human forcing is far faster than rates of forcing increase in the geological past. It is also based on an observation that sea level increased by as much as 10 feet per century at the end of the last glacial period. Hansen’s estimates are consistent with rates of melt observed at the end of the last ice age and mine assume that the speed of human forcing will result in added effects.

The CIRES study provides yet one more observation and related modeling consistent with a far faster than expected rate of ice sheet response. It is likely that we will know within the next couple of decades how this accelerated response translates to rates of ice sheet discharge and related sea level rise. Lastly, it is important to note that geological evidence is not consistent with steady rates of discharge and sea level rise. Unfortunately, major melt events have happened in great pulses that are consistent with catastrophic out-flow events. Such large events would result in serious risks for communities in wide areas surrounding the ice sheets. Tsunami-like melt pulses, therefore, cannot be ruled out. And the high volume of cold water such outbursts deliver to surrounding oceans and environments is also likely to be highly disruptive to established weather and ocean circulation patterns.

It is important to bring these observations to light as the more rapid ice sheet response rates indicated in the CIRES study and by observation heighten the risk for such events.

Links:

Study Explains Surprising Acceleration of Inland Greenland Ice

Evaluation of cryo-hydrolic warming as an explanation for increase ice velocities in the wet snow zone

Video of Greenland Ice Melt Washing out Bridge Over Watson River

This summer, we’ve experienced record melt and heating in Greenland. Reports and satellite pictures from NASA give us a good idea of how much heat the ice sheet is receiving and what areas are melting. But this observation from the ground shows just one of the impacts of this increased melt.

Video provided by M. Tedesco CCNY/CUNY

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