Greenland hits above freezing in March. Air rushing north toward the pole will displace cold Arctic air, forcing it onto the lower 48. This cold air is expected to come into collision with hotter than normal air over the ocean. The result may set off powerful nor’easters for the eastern seaboard by Saturday of next week.
All posts tagged greenland
The OBX Wave Report March 3 — Greenland Heat and a Gale Warning Friday for Future
Posted by robertscribbler on March 3, 2023
https://robertscribbler.wordpress.com/2023/03/03/the-obx-wave-report-march-3-greenland-heat-and-a-gale-warning-friday-for-future/
The Present Threat to Coastal Cities From Antarctic and Greenland Melt
Seas around the world are rising now at a rate of about 3.3 millimeters per year. This rate of rise is faster than at any time in the last 2,800 years. It’s accelerating. And already the impacts are being felt in the world’s most vulnerable coastal regions.
(Rates of global sea level rise continue to quicken. This has resulted in worsening tidal flooding for coastal cities like Miami, Charleston, New Orleans and Virginia Beach. Image source: Ice Melt, Sea Level Rise, and Superstorms.)
Sea Level Rise and Worsening Extreme Rainfall are Already Causing Serious Problems
Last week, New Orleans saw pumps fail as a heavy thunderstorm inundated the city. This caused both serious concern and consternation among residents. Begging the question — if New Orleans pumps can’t handle the nascient variety of more powerful thunderstorms in the age of human-caused climate change, then what happens when a hurricane barrels in? The pumps, designed to handle 1.5 inch per hour rainfall amounts in the first hour and 1 inch per hour rainfall amounts thereafter were greatly over-matched when sections of the city received more than 2 inches of rainfall per hour over multiple hours.
Higher rates of precipitation from thunderstorms are becoming a more common event the world over as the hydrological cycle is amped up by the more than 1 degree Celsius of temperature increase that has already occurred since 1880. And when these heavy rainfall amounts hit coastal cities that are already facing rising seas, then pumps and drainage systems can be stressed well beyond their original design limits. The result, inevitably, is more flooding.
(Dr Eric Rignot, one of the world’s foremost glacial scientists, discusses the potential for multimeter sea level rise due to presently projected levels of warming in the range of 1.5 to 2 C by mid to late Century.)
New Orleans itself is already below sea level. And the land there is steadily subsiding into the Gulf of Mexico. Add sea level rise and worsening storms on top of that trend and the crisis New Orleans faces is greatly amplified.
All up and down the U.S. East and Gulf Coasts, climate change driven sea level rise and a weakening Gulf Stream are combining with other natural factors that can seriously amplify an ever-worsening trend toward more tidal flooding. It’s a situation that will continue to worsen as global rates of sea level rise keep ramping higher. And how fast seas rise will depend both on the amount of carbon that human beings ultimately dump into the Earth’s atmosphere and on how rapidly various glacial systems around the world respond to that insult (see discussion by Dr. Eric Rignot above).
Presently High and Rising Atmospheric Carbon Levels Imply Ultimately Catastrophic Sea Level Rise — How Soon? How Fast? Can We Mitigate Swiftly Enough to Prevent the Worst?
Presently, atmospheric carbon forcing is in the range of 490 parts per million CO2 equivalent. This heat forcing, using paleoclimate proxies from 5 to 30 million years ago, implies approximately 2 degrees Celsius of warming this Century and about 4 degrees Celsisus of warming long term. It also implies an ultimate sea level rise of between 60 and 180 feet over the long term. In other words, if atmospheric carbon levels are similar to those seen during the Miocene, then temperatures are also ultimately headed for those ranges. Soon to be followed by a similar range of sea level rise. In the nearer term, 1.5 to 2 C warming from the 2030s to late Century is enough to result in 20 to 30 feet of sea level rise.
Of course, various climate change mitigation actions could ultimately reduce that larger heat forcing and final related loss of glacial ice. But with carbon still accumulating in the atmosphere and with Trump and other politicians around the world seeking to slow or sabotage a transition away from fossil fuels, then it goes to follow that enacting such an aggressive mitigation will be very difficult to manage without an overwhelming resistance to such harmful policy stances.
(Antarctic ice loss through 2016. Video source: NASA.)
That said, warming and related sea level rise will tend to take some time to elapse. And the real question on many scientists’ minds is — how fast? Presently, we do see serious signs of glacial destabilization in both Greenland and West Antartica. These two very large piles of ice alone could contribute 34 feet of sea level rise if both were to melt entirely.
Meanwhile, East Antarctica has also recently shown some signs of movement toward glacial destabilization. Especially in the region of the Totten Glacier and the Cook Ice Shelf. But rates of progress toward glacial destabilization in these zones has, thus far, been slower than that seen in Greenland and West Antarctica. Present mass loss hot spots are in the area of the Thwaites Glacier of West Antarctica and around the western and southern margins of Greenland.
(Greenland ice loss through 2016. Video source: NASA.)
With global temperatures now exceeding 1 C and with these temperatures likely to exceed 1.5 C within the next two decades, it is certain that broader heat-based stresses to these various glacial systems will increase. And we are likely to see coincident melt rate acceleration as more glaciers become less stable. The result is that coastal flooding conditions will tend to follow a worsening trend — with the most vulnerable regions like the U.S. Gulf and East Coasts feeling the impact first. Unfortunately, there is risk that this trend will include the sudden acceleration of various glaciers into the ocean, which will coincide with rapid increases in global rates of sea level rise. In other words, the trend for sea level rise is less likely to be smooth and more likely to include a number of melt pulse spikes.
Such an overall trend including outlier risks paints a relatively rough picture for coastal city planners in the 1-3 decade timeframe. But on the multi-decade horizon there is a rising risk that sudden glacial destabilization — first in Greenland and West Antarctica and later in East Antarctica will put an increasing number of coastal cities permanently under water.
Rapid Mitigation Required to Reduce Risks
The only way to lower this risk is to rapidly reduce to zero the amount of carbon hitting the atmosphere from human sources while ultimately learning how to pull carbon out of the atmosphere. The present most rapid pathway for carbon emissions reductions involves an urgent build-out of renewable and non-carbon based energy systems to replace all fossil fuels with a focus on wind, solar, and electrical vehicle economies of scale and production chains. Added to various drives for sustainable cities and increasing efficiency, such a push could achieve an 80 percent or greater reduction in carbon emissions on the 2-3 decade timescale with net negative carbon emissions by mid Century. For cities on the coast, choosing whether or not to support such a set of actions is ultimately an existential one.
Links:
Fragmenting Prospects For Avoiding 2 C Warming
Scientists Just Uncovered Another Troubling Fact About Antarctica’s Melting Ice
It Wasn’t Even a Hurricane, But Heavy Rains Flooded New Orleans as Pumps Faltered
Why Seas are Rising Faster in Miami
Ice Melt, Sea Level Rise, and Superstorms
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Posted by robertscribbler on August 18, 2017
https://robertscribbler.wordpress.com/2017/08/18/the-present-threat-to-coastal-cities-from-antarctic-and-greenland-melt/
Early Greenland Melt Spike Possible as Forecast Calls for Temperatures of up to 50 F Above Average
Greenland — a region vulnerable to the slings and arrows of human-forced climate change — appears set to experience both considerable warming and a significant melt spike this week.
Starting on Wednesday, May 3, a sprawling dome of high pressure is expected to begin to extend westward from the far North Atlantic and out over Iceland. As the high pressure dome builds to 1040 mb over the next couple of days, its clockwise flow will thrust abnormally warm and moist air northward out of the Atlantic. This air-mass is expected first to over-ride eastern Greenland, then run up into Baffin Bay, finally encompassing most of the island and its vast, receding glaciers.
(May 5, 2017 GFS model run as shown by Earth Nullschool is predicted to produce widespread above-freezing temperatures over the surface of the Greenland Ice Sheet. Such warming is expected to be accompanied by rainfall over a number of glaciers. Image source: Earth Nullschool.)
Liquid precipitation is then expected to start falling over southern sections of the Greenland Ice Sheet as temperatures rise to 1-6 C (33 to 43 F) or warmer. Since water contains more latent heat energy than air, such rainfall is likely to produce more melt than would otherwise be caused by a simple temperature rise.
For those of us living in more southerly climes, a temperature of 6 C (43 F) may not sound very warm. But for the northeastern region of Greenland shared by the Zachariae, Brittania, Freja, and Violin Glaciers, such temperatures far exceed ordinary expectations for early May. They are anything but normal. In fact, the building influx of heat is more reminiscent to readings Greenland would have tended to experience during summer — if at all — under past climate averages.
(GFS model predictions for May 4 show widespread liquid precipitation falling over southern Greenland. Image source: Climate Reanalyzer.)
Unfortunately, the new climate presented by human-forced warming is now capable of producing some rather extraordinary temperature extremes. And the anomaly ranges that are predicted for the coming week are nothing short of outlandish.
According to climate reanalysis data, by May 5th, temperatures over northern and eastern Greenland are expected to range between 15 C above average over a wide region and between 20 and 28 C above average in the northeast. For the Fahrenheit-minded, that’s 27 to 50 degrees F above normal. Or the equivalent of a 102 F to 125 F May day high in Gaithersburg, MD.
(An amazing temperature spike is expected to ride up and over Greenland on May 3 to May 5. This warming is expected to produce very extreme above average temperatures for this time of year. Image source: Global and Regional Climate Anomalies.)
Overall excessions for Greenland temperature are also predicted to be quite extraordinary for the day — hitting nearly 9 degrees Celsius (16 F) above average for the whole of this large island. So much warmth extending so far inland and combining with liquid precipitation, if it emerges as predicted in these GFS climate models, is likely to produce a significant early season melt spike — especially over southern and eastern Greenland. In places, these temperatures exceed expected normal summer conditions for Greenland’s glaciers. So it is difficult to imagine a situation where a significant surface melt spike does not occur if these predicted temperatures emerge.
Links:
Global and Regional Climate Anomalies
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Posted by robertscribbler on May 1, 2017
https://robertscribbler.wordpress.com/2017/05/01/early-greenland-melt-spike-possible-as-forecast-calls-for-temperatures-of-up-to-50-f-above-average/
Large Sections of Greenland Covered in Melt Ponds, Dark Snow
Over the past couple of days, temperatures across the Greenland Ice Sheet have really ramped up. The result has been a pretty significant mid-to-late season melt pulse. According to NSIDC, nearly 40 percent of the ice sheet surface has been affected by surface melt during recent days. And Greenland ice mass balance appears to have also taken a hit.
This surface melt pulse is, arguably, best portrayed in the satellite imagery:
(Large section of Western Greenland near the Jackobshavn Glacier experiencing significant surface melt on July 20, 2016. Image source: LANCE MODIS.)
On July 20th, this approximate 300 x 70 mile swath of Western Greenland shows a number of distinct strong melt features. Near the interior edge of the melt zone we notice the light blue coloration indicative of widespread and general surface melt. From the satellite, this bluing gives the impression of a thin layer of surface water covering a widespread area of the ice sheet. But it is more likely that the blue tint comes from a plethora of small melt ponds and rivers that blend together in the lower resolution satellite shot to lend the impression of ubiquitous water coverage.
Large Melt Ponds, Dark Snow Over Western Greenland
Further in, we notice the darker blue swatches that indicate large melt ponds. Some of these ponds are quite extensive — measuring 1/4 to up to 1 mile in length. Ponds of this size tend to put a lot of pressure on the Greenland surface and can pretty quickly bore down into the ice sheet’s depths and interior. The water then either becomes locked in the ice — forming a kind of subglacial lake — or flows to base regions of the glacier where it can lubricate the ice — causing it to speed up.
(Close up satellite shot shows 1/4 to 1 mile long melt ponds, general melt ponding and a darkened Greenland Ice Sheet. Image source: LANCE MODIS.)
Still closer to the ice edge we find greatly darkened patches of ice. Darkening occurs when ice melt reveals and thickens past layers of ice sheet dust and soot accumulation. Each year, winds carry dust from land masses and soot from fires — which now, due to rapid Earth warming, burn more frequently over the Arctic and near-Arctic — to the ice sheet where it accumulates. This darker material is then covered by the annual layers of snowfall. If enough snow and ice melts, the yearly layers of dust and soot accumulation can concentrate into a gray-black covering. Such a covering is clearly visible in the July 20 satellite imagery above.
According to Dr. Jason Box, as much as 5.6 percent of the Greenland Ice Sheet was covered by this darkening, which he calls Dark Snow, as recently as 2014. Darkening of the Greenland ice sheet can accelerate melt as it reduces the ice sheet’s ability to reflect the sun’s rays — resulting in more overall heat absorption.
Substantial Northeastern Greenland Melt Also Visible
(Zacharie Isstrom Glacier in Northeastern Greenland shows significant melt in July 20 satellite shot. Image source: LANCE MODIS.)
Though surface melt and darkening is quite extensive along the southwestern flank of Greenland, toward the north and east, widespread surface melt, ponding and ice darkening is also visible over sections of the Zachariae Glacier. Here, in a far northern section of Greenland that borders the Arctic Ocean, we find an approximate 100 x 20 mile region of melting and darkening ice. Note the tell-tale bluing and dark gray patches visible in the above image.
For this region, ice has tended to experience more melt during recent years as sea ice within the Fram Strait and Greenland Sea has receded. This has revealed more darker ocean surfaces which, in turn, has absorbed more incoming solar radiation resulting in increased warming for this section of Greenland.
Conditions in Context — Human-Forced Warming Pushing Greenland to Melt Faster
Overall, Greenland melt is this year less extensive than the record 2012 melt season. However, the current mid-to-late season pulse has forced a big melt acceleration that may result in melt that exceeds 250 billion tons of ice loss for 2016 (or the average over recent years). In the pretty near future, continued high global temperatures and additional warming due to human fossil fuel emissions will almost certainly push Greenland to melt at a faster pace.
To this point, the Earth has now warmed by more than 1 C above Preindustrial temperatures. And a range of 1-2 C warming from this baseline in past climate eras such as the Eemian resulted in a 10-20 foot rise in world ocean levels. We’re in this temperature range now. So that’s pretty bad news for sea level rise — to which Greenland now contributes enough melt to lift seas by about 0.75 mm every year. The only real questions at this point are how fast will that already substantial melt accelerate, and will we halt fossil fuel burning swiftly enough to slow it down.
Links/Attribution/Statements
The National Snow and Ice Data Center
These Stunning Photos of Greenland’s Dark Snow Should Worry You
The Dark Snow Project (please support)
Hat tip to Andy in San Diego
Hat tip to DT Lange
Scribbler-sponsored note on Trump:
Trump Chooses Climate Change Denier as Energy Advisor
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Posted by robertscribbler on July 21, 2016
https://robertscribbler.wordpress.com/2016/07/21/large-sections-of-greenland-covered-in-melt-ponds-dark-snow/
At Least 20-75 Feet of Sea Level Rise Already Locked In? Putting Climate Central’s Surging Seas Into Context
“There are some recent modeling efforts that now show you could get a section of the Antarctic ice sheet, several meters worth of sea level rise, to go in a decade. We used to think it was centuries.” — Andrea Dutton Geochemist at the University of Florida.
* * * * *
Recent reports out from Climate Central and supported by the work of experts show that a sea level rise of at least 6 meters could already be locked in. And as bad as that sounds, a six meter sea level rise from the warming already set in motion by high atmospheric greenhouse gas levels and likely to come from further human emissions could be a best-case or even unrealistic scenario.
To get an understanding as to why so much water may be heading toward the coastal cities of the world, enough water in a 6 meter rise to set off a mass migration of hundreds of millions away from the world’s coasts (just 1.1 meters is enough to flood out 150 million people), it helps to take a good, hard look at paleoclimate. In studying past, warmer, climate states, we can get an idea how much additional sea level rise might be in store. When looking at these past climates for comparison, the key readings to keep in mind are — temperature, greenhouse gas level, and related sea level.
A Question of Whether We Lock in Greenhouse Gas Levels Comparable to Past Climates
Starting with the current climate that is now being rapidly warmed by human fossil fuel burning, we find that this year peak monthly CO2 levels hit near 404 parts per million. It’s a value fast approaching the top of this key greenhouse gas’s range during the Pliocene around 3.5 million years ago. A time when temperatures were 2-3 degrees Celsius hotter and sea levels were between 25 and 75 feet higher than they are today.
(What Virginia Beach looks like after 6 meters of sea level rise. Notably, about everyone I knew as a child or who still lives in VB now is under water in this scenario. Image source: Climate Central.)
Looking at the climate situation in this way tends to elicit a bit of an ‘oh crap’ response. And it should. For all other things being equal, if CO2 levels were to remain so high over the course of a few Centuries, that’s where we’re headed. Toward a world with 2-3 C hotter temperature and 25 to 75 foot higher seas.
But the atmosphere of today is only a rough allegory to that of Pliocene times. In addition to CO2, our airs now host expanding volumes of other greenhouse gasses — exotic and common. A vast majority of which are emitted as a result of fossil fuel burning, extraction, and industrial processes. So to compare our atmosphere to that of the period around 3.5 million years ago and expect the same results with regards to temperature and sea level would be unrealistic. Current methane readings alone — in excess of 1800 parts per billion — now hit levels likely twice that of the Pliocene. And methane is a greenhouse gas with a global warming potential equal to 20 to 120 times that of CO2 over timescales relevant to current human civilization.
As a result of this additional accumulation of methane and other gasses, this year’s atmosphere is a closer allegory to past atmospheres containing an equivalent of about 484 parts per million CO2 (CO2e). Such times, occurring 15-25 million years ago, hosted sea levels that were more than 100 feet (and possibly as much as 200 feet) higher than today.
It is for this reason that we should view Climate Central’s recent and excellent report on sea level rise — based on Paleoclimate and predicting that at least 20 feet of sea level rise could already be locked in — with a bit of concern. At issue with the report are two factors. The first is that the study bases its findings on predicted temperature increases for the 21st Century only. A process established by IPCC-based studies in which it is assumed that 2 degrees Celsius warming over the course of this Century is, perhaps, the best possible target we can hit through a pretty rapid transition to a zero or near-zero carbon civilization. Implied in this IPCC approach is limiting global CO2 accumulation to 450 parts per million or less. A level that also implies a 530 to 550 parts per million CO2e when other gasses are added in unless all the methane overburden falls out due to its short atmospheric lifetime (about 8 years). A dicey assumption at best considering that at least some and possibly all of that overburden could be maintained by feedbacks now at play in the Arctic and in the world’s land and ocean systems.
(At six meters of sea level rise, Miami is completely submerged. Image source: Climate Central.)
In worse cases, we could see the methane overburden expand in the event that the Arctic carbon stores are less stable than we’d hoped. So while 450 parts per million CO2 might limit us to between 2 and 2.3 C warming this Century, 530 to 550 parts per million CO2e gets us to 2.2 to 2.9 C.
The second issue is that we are only looking at warming for the 21st Century. Due to the long term warming impact of CO2 and other greenhouse gasses on the climate system in total, each 1 C worth of warming this Century implies about 2 C worth of warming long term (ESS sensitivity). So hitting the 2 C target by 2100 gets you to 4 C after many Centuries. And hitting a 550 parts per million CO2e threshold means about 2.7 to 2.9 C 21st Century warming and 5.5 to 5.8 C long term warming. An upper range that is nearly enough to melt all the land ice on Earth and raise sea levels by nearly 240 feet.
How Fast Could Sea Levels Rise?
At least 6 meters indeed! In the 550 parts per million CO2e case, we have one of the better global human carbon emissions scenarios meeting with one of the somewhat more pessimistic Earth Systems response scenarios (but not the worst case) for an absolutely terribly catastrophic outcome. An outcome made even more terrifying by the fact that it is in the mid-to-low range of overall projected greenhouse gas forcings for this Century. In other words, 2 C warming this Century can start to look like a pretty bad outcome for the long haul and we’d probably best be trying to hit well below the implied 450 ppm CO2 target (as Hansen and others have warned). And to this point, we had better move very fast on emissions reductions, because the longer even current greenhouse gas levels are maintained the more likely we hit ice sheet destabilizations that push world ocean levels closer and closer to the Pliocene’s or Miocene’s swollen seas.
(Just 1 C worth of global warming from 22,000 years BP to 15,000 years BP was enough to set off rapid sea level rise during the end of the last ice age. We are fast approaching the 1 C warmer than 1880s thresholds now. Image source: Commons and Livescience.)
Which brings us to a final question hinted at in the header — how fast could sea levels rise if human forced warming approaches 2 C or more this Century? The modelling efforts Dutton hinted at shows that West Antarctica alone can contribute meters of sea level rise over the course of just decades. And going back to paleoclimate studies of the end of the last ice age we find hints that somewhere between 1 and 2 C worth of warming can trigger very large and rapid glacial outbursts (that then increased sea levels by as much as 16 feet per Century). Finally, recent glacier surveys from Antarctica to Greenland have found extensive and expanding destabilization. Efforts and evidence that imply the 39 inches of sea level rise predicted by IPCC this Century may be quite conservative, even under the better case emissions scenarios.
Links:
Sea Level Could Rise at Least 6 Meters
Antarctica and Greenland’s Simultaneous Destabilization
Concern Over Catastrophic Methane Release
A Faustian Bargain on the Short Road to Hell
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Posted by robertscribbler on July 14, 2015
https://robertscribbler.wordpress.com/2015/07/14/at-least-20-75-feet-of-sea-level-rise-already-locked-in-putting-climate-centrals-surging-seas-into-context/
You Know There’s Something Wrong When Vast Expanses of Greenland Look Like A Blackened Volcanic Crater
Lowest albedo on record for Greenland.
That’s what data provided by NASA and processed by polar scientist Jason Box are showing for August of 2014.
But it doesn’t take a polar scientist to tell you something is dreadfully wrong with this:
(Swaths of Greenland’s Ice Sheet look more like a volcanic crater than mountains of frozen water. Video source: Dark Snow.)
The above video, provided by the Dark Snow Project and featured on Peter Sinclair’s fantastic Climate Crocks blog, shows a vast swath of the Greenland Ice Sheet from helicopter. Miles and miles of previously pristine ice now show a blackening similar in color to volcanic basalt. A color vastly uncharacteristic of Greenland and more suited to melting and salted snow in an urban parking lot.
Melt is a primary driver of such widespread blackening of the Greenland Ice Sheet. Compaction and removal of snow through melting of the surface layer uncovers dirt, dust and soot left over through the years and millennia, depositing it in a dense layer just beneath the newly melted and washed away snow.
Snow and ice darkening is also compounded by vastly expanding Arctic wildfires. And this year featured the most severe outbreak of wildfires on record for the Northwest Territory of Canada together with extreme and explosive fires throughout Arctic Siberia.The dark soot ejected in immense plumes from these fires is borne aloft by the winds, eventually falling together with rain and snow over the Greenland Ice Sheet.
Lastly, manmade sources of black and brown carbon are also implicated in the great ice sheet’s blackening. And, during recent years, with the explosion of dark particulate sources in developing countries and through global slash and burn agriculture, more and more dark particulate from human activities is finding its way to the great ice sheet.
The net effected is Greenland ice sheet albedo dropping like a rock.
(Falling like a rock. Greenland Ice Sheet albedo hits record low for August of 2014. Data source: NASA MOD10A1. Data Processed by: Dr. Jason Box.)
Albedo is a measure of reflectivity. The less reflective an ice sheet is, the more vulnerable it is to melting through direct heating by solar radiation. The ice sheet surface absorbs more energy from the sun’s rays as reflectivity falls and this process, in turn, further hastens a melt that is already being amplified by human-caused atmospheric and ocean heating.
But charts and graphs do little justice to this ongoing tragedy. In looking at vast stretches of ice, now colored an ominous grey-black, blanketing Greenland, it becomes all-too-easy to realize that we are likely witnessing the start of the Great Ice Sheet’s demise.
Links:
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Posted by robertscribbler on October 1, 2014
https://robertscribbler.wordpress.com/2014/10/01/you-know-theres-something-wrong-when-vast-expanses-of-greenland-look-like-a-blackened-volcanic-crater/
Greenland Ice Loss Increases Fivefold From Late 1990s, West Antarctica Not Far Behind
In the early 1990s, it would have been hard to imagine the rates of glacial ice loss we are seeing now.
There were few ways to accurately measure the Greenland Ice Sheet’s mass. Snow fell, glaciers calved. But observations seemed to show that the great, cold ice pile over Greenland was in balance. Snow gathered at the top, glaciers calved at the edges, but human heating of the atmosphere had yet to show plainly visible effects.
At that time, climate scientists believed that changes to the ice, as a result of human caused heating, would be slow and gradual, and would probably not begin to appear in force until later in the 21st Century.
(Extensive surface melt ponding, dark snow near the rapidly melt Jakobshavn Glacier on the West Coast of Greenland in early August of 2014. Image source: LANCE MODIS.)
Ice Sheet Response Starts Too Soon
By the late 1990s, various satellites had been lofted to measure the gravity, mass and volume of structures on the Earth’s surface. These sensors, when aimed at the great ice sheets, found that Greenland, during a period of 1997 to 2003 was losing mass at a rate of about 83 cubic kilometers each year.
This rate of ice loss was somewhat small when compared to the vastness of the ice sheet. But the appearance of loss was early and, therefore, some cause for concern. More monitoring of the ice sheet took place as scientists continued their investigation, for it appeared that the ice sheet was more responsive to human warming than initially believed.
A Doubling After Just Six Years
By 2009 another set of measures was in and it found that the six year period from 2003 to 2009 showed a near doubling of ice mass loss from the Greenland Ice Sheet. Rates of loss had jumped from 83 cubic kilometers each year to around 153 cubic kilometers. The doubling caused consternation and speculation among climate scientists. Greenhouse gas heat forcing was rapidly on the rise and the world’s oceans were warming faster than expected as human emissions continued along a worst case scenario path. It appeared that the ocean was delivering heat to the ice sheet bases even as atmospheric warming was melting larger areas upon the ice sheet surface.
These changes to the massive ice sheets were occurring far more rapidly than previously considered.
(Hundreds foot high edge of the Greenland Ice Sheet in Kangerlussuaq as seen at the end of a long valley and across a cold estuary. Image source: EISCAT Scientific Association.)
The potential for a 3, 6, or even 9 foot or more sea level rise by the end of the 21st Century was raised. Perhaps even more ominous, global climate models were showing that rapid ice melt in Greenland and West Antarctica, should it occur, would play havoc with world weather systems. It was this jump in ice loss, in part, that spurred climate scientist and then head of NASA GISS, Dr. James Hansen to write his book The Storms of My Grandchildren as a warning that rapid mitigation in human greenhouse gas emissions along with a stabilization of atmospheric CO2 at 350 ppm would probably be needed to prevent severe consequences from human-caused warming.
But humans kept emitting at a break-neck pace, spending far more money to build coal, gas and oil based technology, than to reduce energy consumption through efficiencies or behavioral change or to invest in alternatives like wind and solar.
Melt Rates Surge Yet Again
And so, by January of 2014, heat forcing had continued to accumulate at a very rapid pace. CO2e heat forcing had spiked to 481 ppm, enough to melt the entire Greenland Ice Sheet and much of Antarctica as well, if maintained or increased over a long period.
And the Greenland Ice sheet was, indeed, melting at an ever faster clip. For the most recent assessment found that the loss rate from Greenland had again more than doubled — hitting a 375 cubic kilometer per year average during the period of January 2011 through January of 2014.
(Greenland Ice Sheet elevation change in meters as found in a recent report by the Alfred Wegner Institute. Note that all Greenland edge zones are now experience elevation losses. Due to higher elevations at the center of the ice sheet, elevation loss at the edge has an effect that speeds ice sheet motion toward the sea. The effect is similar to pushing down the edge of a plastic swimming pool, but on a much larger scale and with somewhat slower moving ice.)
It was an extraordinary rate of melt now 4.7 times faster than in the period from 1997 to 2003 and 2.5 times faster than during 2003 to 2009. But, likely, it is but one more milestone on the path to even faster melt.
The same study that found the Greenland melt acceleration also saw a tripling of the melt rate of West Antarctic since 2003 to 2009. Together, the ice sheets were found to contribute a combined mass loss of 503 cubic kilometers per year between Greenland and West Antarctic. This vast, and still apparently rising, loss now meant that the two great ice sheets were contributing at least one millimeter per year to sea level rise.
Likely Grim Future For Sea Level Rise
It is likely that mass rate losses will continue to increase until some kind of break or negative feedback comes into play. Similar rates of melt increase would mean an annual 5-8 millimeter sea level rise by 2035 due to Greenland and Antarctic melt on top of a 2-3 millimeter sea level rise from thermal expansion of the oceans and from other melt sources. But even taking into account the cooling effect at the ocean surface from ice melt and fresh water floods, one could easily envision the feared 1-3 foot sea level rise by sometime near mid century and the even more concerning 3-9 foot sea level rise amidst a very intense battle between hot and cold weather systems through to century’s end.
As of 2014, it appears the conditions leading up to the warned of “Storms of My Grandchildren” are well in play and rapidly building.
Links:
Alfred Wegner Institute: Elevation Change of the Greenland Ice Sheet
Greenland Ice Loss Doubles From Late 2000s
The Storms of My Grandchildren
Hat Tip to TodaysGuestIs
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Posted by robertscribbler on August 21, 2014
https://robertscribbler.wordpress.com/2014/08/21/greenland-ice-loss-increases-fivefold-from-late-1990s-west-antarctica-not-far-behind/
Smokey Greenland Sees Another Summer of Substantial Melt
(Smoke from Record Northwest Territory Wildfires on August 1, 2014 crossing Baffin Bay and the West Coast of Greenland. Image source: LANCE-MODIS.)
According to our best understanding of paleoclimate, at current greenhouse gas levels of 402 parts per million CO2 and 481 parts per million CO2e, the Greenland Ice Sheet eventually melts out entirely. It’s a level of atmospheric heat forcing we’ve already set in place, a level that keeps rising at a rate of about 2.2 parts per million CO2 and 3 parts per million CO2e each and every year due to our ongoing and reckless carbon emissions. And it’s a level that is already starting to receive substantial additions from destabilizing permafrost carbon together with likely increasing releases from sea bed methane stores.
In this, rather stark, geological, climatological and physical context, we ask the question — is it possible for us to stop a wholesale collapse of Greenland’s ice? And we wonder, how long can the ice sheet last as human greenhouse gas forcings together with ongoing releases from some of Earth’s largest carbon stores continue to rise?
(Extensive melt ponds, Dark Snow on West Face of Greenland Ice Sheet near the Jakobshavn Glacier on July 30, 2014. Extensive darkening of the ice sheet surface, especially near the ice sheet edge, is resulting in more solar energy being absorbed by the ice sheet. Recent studies have shown that edge melt results in rapid destabilization and speeds glacier flows due to the fact that edge ice traditionally acts like a wall holding the more central and denser ice pack back. Notably, the Jakobshavn is currently Greenland’s fastest glacier. Image source: LANCE-MODIS.)
For ultimately, our ability or inability to rapidly mitigate and then draw down extreme levels of atmospheric greenhouse gasses will provide an answer these key questions. And whether we realize it or not, we are already in a race against a growing Earth Systems response that may eventually overwhelm our efforts, if we continue to delay for too long.
But there’s a lot of inertia in the ice. It represents aeons and aeons of ancient cold locked in great, mountain-high blocks. And its eventual release, which is likely to continue to ramp higher and higher this century, is bound to result in a temporary and weather-wrecking outrush of that cold causing dramatic swings in temperature and climate states to be the rule of the day for Greenland as time moves forward.
(Large melt ponds, extensive surface water over Zachariae Glacier in Northeast Greenland on July 25 of 2014. For reference, the larger melt ponds in this image range from 1 to 4 kilometers at their widest points. The Zachariae Glacier sits atop a deep, below sea level channel that runs all the way to a massive below sea level basin at the center of the Greenland Ice Sheet. This Glacier is now one of more than 13 massive ice blocks that are moving at ever increasing velocity toward the ocean. Image source: LANCE-MODIS)
So we should not expect any melt to follow a neat or smooth trend, but to instead include large variations along an incline toward greater losses. In short, we’ve likely locked in centuries of great instability and variability during which the great ice sheets are softened up and eventually wither away.
Another Year of Strong Greenland Melt
In the context of the past two decades, the 2014 summer melt has trended well above the 30 year average in both melt extent and surface mass losses. Though somewhat behind melt during 2012, 2014 may rank in the top 10 melt years with continued strong melt in various regions and an overall substantial loss of ice mass.
Surface melt extent appears to be overall above 2013 values, ranging well above the 1981-2010 average, but significantly below extents seen during the record 2012 melt:
(Last three years of surface melt extent with the most current melt graph for the 2014 melt season at the top and the preceeding years 2013 and 2012 following chronologically. Dotted blue line indicates 1981-2010 average. Top three surface melt years in the record are 2012, 2010 and 2007, respectively. Image source: NSIDC.)
Overall, 2014 showed four melt spikes above 35% melt coverage with three spikes nearing the 40% melt extent coverage mark. By contrast, 2013 only showed two such melt spikes, though the later spike was slightly more intense than those seen during 2014. 2012’s 150 year melt, on the other hand, showed melt extents ranging above 40 percent from mid June to early August with two spikes above 60% and one spike above 80%.
Losses of mass at the surface also showed above average melt trends, but with net melt still below both 2013 and 2012:
(Greenland surface mass balance trend for 2014 [blue line] compared to mean for 1990 to 2011 [gray line] and record melt year of 2012 [red line]. Image source: DMI.)
2012 was a strong record year and, on average, we’d expect to see the record jump back to lower levels after such a severe event. However, there’s little to indicate that either 2013 or 2014 have bucked the trend of ongoing and increasing surface melt over Greenland. To the contrary, that trend is now well established with yearly surface mass losses now taking place during all but one of the last 13 years. And there is every indication that 2014 will be a continuation of this trend.
Basal, Interior Melt Not Taken Into Account in the Surface Measure
While surface measures are a good measure of melt on the top of the ice sheet, it doesn’t give much of an idea of what’s happening below the first few feet. There, during recent years, sub surface melt lakes have been forming even as warming ocean waters have eaten away at the ice sheet’s base. And since more than 90% of human-caused warming ends up in the world’s oceans even as many of Greenland’s glaciers plunge hundreds of feet into these warming waters, one might expect an additional significant melt to be coming from the ocean-contacting ice faces.
We can see an indication of the severe combined impact of basal, interior and surface melt in the GRACE mass measurements of the Greenland Ice Sheet since 2002. A record that finds a precipitous and increasing rate of decline:
(Greenland cumulative mass loss through mid 2013. Data provided by the GRACE satellite gravity sensor. Image source: NOAA.)
It is this ongoing overall mass loss that tells the ice sheet’s full tale. One that now includes an ever-increasing number of destabilized glaciers speeding more and more rapidly seaward.
Links:
Nature: Human Warming Now Pushing Entire Greenland Ice Sheet Into the Ocean
The Arctic Methane Monster Exhales
Large Methane Plumes Discovered on Laptev Continental Slope Boundary
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Posted by robertscribbler on August 1, 2014
https://robertscribbler.wordpress.com/2014/08/01/smokey-greenland-sees-another-summer-of-substantial-melt/
The Glacial Megaflood: Global Warming Poses Growing Glacial Outburst Flood Hazard From Himalayas to Greenland and West Antarctica
Large Melt Lake, Greenland
(Image source: Marco Tedesco)
It’s been yet one more summer of anomalous weather events resulting from human-caused warming. Massive floods have spanned the globe, shattering records that have stood for 50, 100, or even 500 years. In other regions, record droughts and heatwaves have resulted in thousands of heat injuries and hundreds of deaths with the southeast Asian heat dome alone reported to have hospitalized tens of thousands and resulted in at least 100 deaths in China, Japan and Korea. These droughts and heatwaves created hazardous water shortages putting communities from the American Southwest to Eastern China at risk of severe damage and loss of ability to supply growing water demands. They also sparked massive and freakish wildfire complexes that damaged or destroyed hundreds of buildings or left enormous burn scars over landscapes from tropical regions to the Arctic tundra — some of which have now born the excessive insults of major fires for ten years running. The term Arctic heatwave has become common parlance. And the combination of extreme weather has resulted in widespread damage to crops and related livestock industries.
All these extreme events, in concert, are visible proofs of a climate emergency that is just starting to ramp up. Few have received the attention they warrant in the mainstream press — either singly, or together as an overall dangerous alteration to the world’s climate and weather.
But of all these, rather ominous, events, one stands out as a warning of a new, out of context, threat — a set of freakish floods in the Himalayan highlands. Floods set off by a combination of high altitude rainfall and the collapse of damns formed around growing glacial melt lakes in a region undergoing very rapid melt and warming.
(Aftermath of Glacial Outburst Flood at Kedarnath, India)
Glacial Outburst Flooding in Kedarnath
Since the early 2000s, average temperatures in the Himalayan Mountains in northern India have increased by about 1 degree Celsius, around 4 times the global average. This steady temperature rise has resulted in a gradually increasing melt of the massive glaciers along this major mountain chain featuring the tallest peaks in the world.
Over the past decade, immense glaciers along this range have witnessed unprecedented melt with many glaciers losing up to 30% of their mass. Predictions show total melt for most glaciers likely to occur under current rates of warming and fossil fuel emission by around the end of this century. The massive and unprecedented rate of melt has fueled the formation of numerous very large and growing glacial melt lakes throughout the Himalayan region. So far, about 200 of these amazing 20,000 melt lakes have outburst in flood events that are a direct result of human caused warming and related glacial melt in the Himalayas.
One such melt lake developed and filled over the past few years in a region just 4 kilometers to the north of the Indian village of Kedarnath. It was just one of the hundreds of newly formed lakes that developed and steadily grew in size over the past five years. By June of 2013, the lake had filled to capacity. Its high altitude waters held back only by a thin damn of sediment pushed out by the now, mostly melted, glacier. Then came the rains.
In the days leading up to June 17, a massive rainfall event inundated the Kedarnath region, spilling waters into an already over-filled glacial melt lake north of Kedarnath. By June 17, a tipping point was reached and the sediment damn holding back the brimming glacial melt waters erupted, unleashing what amounted to a mountain tidal wave upon Kedarnath and a massive area stretching 40 miles downstream from the glacial outburst.
This immense flood swept away more than 6,000 people who are now presumed dead after one of the worst flood events in Indian history, an event that would almost certainly have never happened without human-caused warming.
“The Kedarnath floods may be only a small precursor to never-seen-before mega floods,” says Maharaj K. Pandit, director, Centre for Inter-disciplinary Studies of Mountain & Hill Environment, Delhi University. Scientists like him believe that the high precipitation on June 16 rapidly filled up Chorabari Tal, a glacial lake less than 4 km upstream from Kedarnath, and the continuing downpour the next morning caused the lake to overflow and possibly burst out from its loosely packed rim of moraines (glacial sediments).
Increasing Rainfall Over Himalayan Glaciers and Growing Risk of Megafloods
Himalayas Melting
(Image source: India Today)
According to reports by Indian scientists, rainfall rates over the Himalayan mountain chain are increasing even as rates of snowfall events are falling. Overall, precipitation is increasing by 30 percent, but more and more of this greater volume of precipitation is coming down as rain. The rain provides a double stress to glaciers in that it delivers more heat to already rapidly melting ice masses and the added run-off creates large pulses that both erode ice sheets and sediment deposits that keep both ice and water locked in. Eventually, water erosion and heat stress is too great, melt rates are too high and sediment and ice damns can no longer hold. The result is a massive and very dangerous flood event called a Glacial Outburst Flood (GLOF).
The Himalayans have seen increasingly severe GLOFS since 1929 when the first major such event emerged. Overall, 200 GLOFS have inundated various regions surrounding the Himalayans with major resultant damage to infrastructure and loss of human life. But with hundreds of new lakes forming over the past five years and with rates of glacial melt spiking, the risk for increasingly catastrophic GLOFS is growing.
As noted above, there are currently 20,000 large melt lakes throughout the Himalayan chain and, with temperatures in the region expected to increase by another 1-2 degrees Celsius before 2050, the number and size of glacial melt lakes is bound to grow. More rainfall will occur at higher and higher elevations, pushing glacial melt lake levels higher and higher. In the end, millions of downstream residents are at increasing risk of Glacial Outburst Floods.
With human climate change pushing warming at such a rapid and unprecedented rate, it is only a matter of time before more of these amazingly dangerous events take place. Global carbon emissions hit a new high in 2012 and a start to global greenhouse gas reductions, without serious and immediate global policy measures, is years to decades away. So it is highly likely that risks for large GLOFS will continue to increase in India and in other nations bordering the Himalayan mountain chain.
Stark Implications for Greenland, West Antarctica
Anywhere in the world where major ice sheets and glaciers exist, the threat of large Glacial Outburst Floods is growing. Perhaps the starkest manifestation of this risk is visible upon the now, rapidly melting, ice sheet of Greenland.
Since the mid 2000s, Greenland has been melting at a rate of 500 cubic kilometers every year. And due to polar amplification, rates of temperature increase over the Greenland ice sheet have been about double the global average. A recent report published in Nature found that just another .8 degree Celsius rise in global temperature would be enough to push the Greenland ice sheet to the point of no return. In this case, a long-term melting of all the Greenland ice sheet will have been set off by human warming.
But with very rapid melt starting to occur now, it is likely that we are already at the point of large-scale destabilization of the Greenland ice sheet even as we stare down the face of setting in place a total melt scenario over the next few decades (setting off a chain of chaotic events that would likely take centuries to complete). With temperatures continuing to rise over Greenland and with human greenhouse gas forcing and Earth System feedbacks also on the increase, it is highly likely that pace of ice sheet destabilization will continue to accelerate.
Greenland melt lakes, dark snow, August 4, 2013.
(Image source: NASA/Lance-Modis)
The problem with Greenland melt, however, is in many ways far worse than the melt of the massive, though comparatively smaller, Himalayan Glaciers. The Greenland ice sheet is entirely contiguous and has massive depth and a towering elevation of two miles at its center. Glacial Outburst Flood events from such a large source will, therefore, be far, far more catastrophic.
In the Greenland melt dynamic, multiple glacial melt lakes will increasingly form over the surface of the Greenland ice sheet. We can already see such events beginning during current summers. The above shot provided by NASA shows numerous melt lakes forming in the western border of the Greenland Ice Sheet on August 4 of 2013. These melt lakes are many times larger than those seen in the Himalayas with some of them stretching six kilometers in length. In the future, we can expect the size and number of the glacial melt lakes to greatly increase.
Risk of a Greenland Megaflood Arises
With such a large region of ice covered by numerous melt lakes, a kind of ominous tipping point may be reached. During warm summer months, weather systems may pull warmth and moisture over a large section of the Greenland Ice Sheet which is already covered with numerous melt ponds. Temperatures above freezing and a constant flow of moisture emerging from the southern latitudes through a locked in place Jet Stream pattern may ensure that the rain event over these Greenland melt lakes lasts for days or weeks.
Eventually, some of these melt lakes begin to over-top, spilling waters into the already filled lakes lower down on the ice sheet. These lakes then also over-top, contributing ever greater volumes of water to the growing flood.
Depending on how far melt lakes penetrate into the ice sheet, this chain reaction over-topping can proceed for tens or even hundreds of kilometers. By the time the massive flood has reached the lower ice sheet edge, perhaps a kilometer or more below the initial flood source, a massive glacier-originating wave has developed, one that is, perhaps, tens or hundreds of feet in height and with a front covering tens or even hundreds of miles.
Such a powerful outburst megaflood would contain both freezing water and large fragments of ice ripped from the ice sheet as the outburst wave proceeded down the ice sheet. And, like the Kedarnath megaflood, it will also likely contain boulders pulled from adjacent mountains and lands. But this particular event would be far, far worse than any Himalayan outburst flood. It would proceed for hundreds and, perhaps, thousands of miles from the outburst site, leaving a swath of destruction similar to that seen in the worst global ocean tsunami events of recent years.
Melt Lakes Forming Among Terrace-Like Structures on the Greenland Ice Sheet. Set up for Future Large Outburst Megaflood?
We see evidence of such events occurring at the end of the last ice age, with petrified trees imbedded in rock strata up to 500 feet above sea level in the cliffs and mountainsides of Pacific Islands bordering the Arctic. It is thought that these trees were carried by massive glacial outburst floods from the melting Laurentide Ice Sheet which, at the end of the last Ice Age, was thousands of miles away from this tree deposition. The trees found in these deposits are natives to Canada and Alaska and the character of their deposition is indicative of a catastrophic outburst flood event or series of events.
Glacial Outburst Megafloods are among the most dangerous risks posed by rapid Greenland and West Antarctic Ice Sheet melting, warming and destabilization. And Greenland is most likely to see its first manifestations, though Antarctica may follow soon after, over the course of years or decades. Such ice sheet decline will be both chaotic and destructive — with moments of almost unthinkable outburst events proceeding once certain tipping points are reached. Some of these events may already be locked in due to current human forcing and related natural feedbacks. Let us hope that it is possible to prevent their very worst manifestations.
Greenland Outburst Flood of 2012 to be Seen as Minor by Comparison
Should such events occur, a massive outflow of water near the Greenland Ice Sheet during 2012 that washed out a bridge and threatened a local airport will be seen as minor. For comparison, I’ve added the following video:
A major outburst flood issuing from a large section of the Greenland ice sheet would render miniscule even this, very energetic event.
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Posted by robertscribbler on August 19, 2013
https://robertscribbler.wordpress.com/2013/08/19/the-glacial-megaflood-global-warming-poses-growing-glacial-outburst-flood-hazard-from-himalyas-to-greenland-and-west-antarctica/
Global Warming Rolls Climate Dice Yet Again: High Amplitude Jet Stream Wave Brings Late July Melt Surge to Greenland
The old cliche is that lightning never strikes twice in the same place. In weather and climate terms, natural variability makes it highly unlikely that record year will follow record year, even when a forcing, such as human global warming, tends to push in that direction.
In the context of Greenland, it was very unlikely that record melt on the order of around 700 gigatons of ice lost during 2012 would repeat in 2013. That said, even in a year like 2013, where climate attempts a return to the average trend line, it’s entirely clear that conditions are anything but normal.
Throughout late June and much of July, a downward dip in the Jet Stream dominated weather patterns over Greenland. Cold, Arctic air was locked over the massive island, pushing melt rates closer to ‘normal’ for a summer season. The term to use is definitely ‘closer,’ because even during weather conditions that would normally bring colder than average conditions to Greenland, warmth and melt were still above average.
Global warming adds a roll
A metaphor we can use to describe this phenomena of implied variability in a warming system is James Hansen’s climate dice. Imagine that a basic roll of a d10 gives us a typical weather pattern for Greenland. 1 on the dice represents record cold, 10 record warmth, 2 and 3 are colder than average, with 2 being near record lows and 3 being closer to average, 4, 5, 6 and 7 are average, 8 and 9 are hotter than average, and 10 is record heat.
This set of weather and climate possibilities is a basic representation of ‘normal’ for Greenland. But when we add in human climate change and global warming, we are essentially adding a new player to the mix, with its own set of dice. In this case, let’s add a 1d3 to the global warming hand. Now, with the extra dice roll for global warming, the potential for extreme hot, melting years just got far, far more likely and we begin to experience never seen before heat and melt events. But we still end up with colder than average years and normal years, just less of them.
The situation is probably worse than the simulation described above because on the typical 1 to 10 scale we can label 2012 about a 13 (with freakish never seen before record heat and melt) and 2013 through about July 26th a 7.1 — slightly hotter than average with ever so slightly above average melt.
The problem is that June and July were average when they should have been cold. I say this because a high amplitude wave in the Jet Stream flowed down over Greenland, pushing relatively colder air over the sea ice and into the freezer that is still Greenland. Such conditions usually push for colder than average Greenland temperatures and lower than average melt. This period of what should have been colder than average conditions instead resulted only in an abatement of record melt and a return to slightly above average melt.
Mangled Jet Stream switches back to ‘hot’
But now, even this brief respite appears to have evaporated. Over the past couple of weeks, the deep, cooler trough over Greenland eroded, weakening as warmer air pushed into southern Greenland. Now, the trough has completely reversed — becoming a ridge and somewhat mimicking the freakish conditions that occurred during 2012. So slightly above average melt conditions are now starting to swing back toward record melt conditions for this time of year.
You can see the large, high amplitude bulge riding from south to north, carrying air from the south-eastern US all the way north to Baffin Bay and southwestern Greenland, in the Jet Stream map for July 30th below:
(Image source: California Regional Weather Service)
This sudden Jet Stream switch brings back a weather pattern that caused such major melt conditions during summer of 2012 and such warm winter conditions for Greenland as 2012 turned to 2013. And the results, as far as ice melt goes, have been almost immediate. Earlier melt peaks at around 34% of the ice sheet during July were obliterated in one fell switch of atmospheric air flow that, once again, drew warm, temperate air into the Arctic.
Over the past two days, this extra warmth has increased Greenland melt area to above 40%, peaking at near 45% just a couple of days ago. This peak, though not as anomalous as the 90% + melt coverage experienced during early July of 2012, is still about 80% higher than the average melt peak observed for the period of 1981-2010 and more than double the average for melt in late July. It also puts Greenland further into above average melt year territory, possibly shifting the 2013 score from 7.1 to around 8.5.
You can see the melt coverages graph, provided by NSIDC, for the current year below:
(Image source: NSIDC)
The warm air pulse that drove these anomalously high late season melt rates in Greenland appears to have settled in for at least the time being. Temperatures along the Greenland coast range from the upper 30s to the lower 60s — quite warm for this time of year — while summit Greenland is experiencing warmer than average temperatures in the lower 20s (Fahrenheit).
Above average melt when it should have been cold
So what is freakish about 2013 when compared to 2012 is not that it matched a major melt event that will likely stand as a record for the next five years or so, but that in a year where weather conditions would have pushed Greenland to be mostly colder than normal, above average warmth and melt were still experienced. In this case, it becomes very clear that we are rolling with loaded climate dice or, as the illustration above shows, human global warming is adding its own wicked set of rolls.
Links:
California Regional Weather Service
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Posted by robertscribbler on July 30, 2013
https://robertscribbler.wordpress.com/2013/07/30/global-warming-rolls-climate-dice-yet-again-high-amplitude-jet-stream-wave-brings-late-july-melt-surge-to-greenland/
Greenland Ice Melt Accelerates in Early June
(Image source: NSIDC)
After a warm winter, the spring that followed has been a cool one for Greenland. An upswing in the jet stream that had warmed Baffin Bay and the western coast of Greenland through early April faded and ice sheet melt through May has been slower than average.
But over recent days warmer air has moved into Greenland, melting ice along its coastal edges. This warm air influx was driven, in part, by a heat-wave in Scandinavia that then spilled warmer air over the North Atlantic and into the Arctic. This region of warmer air also invaded parts of the northeast coast of Greenland.
As temperatures increased, so did melt rates. By June 4, pace of melt was again well above average.
(Image source: NSIDC)
Melt occurred most intensely along the eastern and northern coasts with lesser amounts showing along the edge of Baffin Bay. Overall, about 15% of the Greenland Ice Sheet was showing melt by June 4.
2013 Compared to Past Years
During 2012, record summer heating caused the entire Greenland ice sheet to melt for some days during July. This kind of melt hasn’t been seen for over 100 years but many scientists are now predicting that 2012 melt paces could be seen as often as twice per decade or more.
And Greenland’s pace of melt is accelerating. During the 2000s rate of Greenland ice melt is five times that of the 1990s. During the past 20 years, Greenland has melted more than in any comparable period during the past 10,000 years.
That’s not to say that every year will be a record year like 2012. At this point, there’s no way we can tell if 2013 will meet or exceed Greenland’s melt during summer a year ago. Usually, it’s not the case that you get back to back records.
So far, the weather pattern hasn’t been as conducive for Greenland melt this year. But, lately, the Arctic has been very unstable and the weather rather unpredictable. So it’s worth keeping a close eye to Greenland as summer progresses.
Links:
Polar Ice Sheets Melting Faster Than Ever
Greenland, Antarctic Melt Speeding Up, Study Finds
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Posted by robertscribbler on June 6, 2013
https://robertscribbler.wordpress.com/2013/06/06/greenland-ice-melt-accelerates-in-early-june/
Greenland Melt Speeding Up; Northern Hemisphere Snow Cover Falling Below Average
(Image source: NSIDC)
Greenland ice sheet melt spiked today, moving into above average territory with nearly five percent of the ice sheet showing surface melt. Influx of warmer air from the south combined with ongoing heat absorption by the ice sheet to push melt levels higher over a broad area of southern Greenland. Temperatures rose above freezing for most of southern Greenland while much colder air remained concentrated to the north.
(Image source: NSIDC)
Over much of the Arctic, warmer air is invading northward. Above freezing temperatures are now common around Hudson Bay, in Northwestern Canada, in Northern Alaska, over sections of the Bering, Beaufort and Kara Seas, and are nearing the coast in East Siberia. Higher temperatures pushing northward have not only set off Greenland melt, but overall Northern Hemisphere snow cover continues to push into lower than average territory.
This rapid melt is especially worthy of note considering the massive amount of snow dropped by major storms this winter over much of the Northern Hemisphere. Should pace of snow melt continue, we may be on track for another record year.
Last year, both Greenland surface ice melt and Northern Hemisphere snow melt plunged into record low territory. Greenland melt was particularly exceptional with nearly 100% of the surface area of Greenland showing melt on certain days during July. The last time a similar level of melt occurred on Greenland was more than 100 years ago. A repeat of this kind of melt at any time within the next decade would be unprecedented. However, given current levels of Arctic warming, such melt is certainly possible.
Loss of tundra in certain regions appears to be one of the key drivers of enhanced snow melt during summer time. Arctic warming over the past few decades has continued to push the tundra line northward. As a result, snow is less resilient in northern regions come summer.
Links:
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Posted by robertscribbler on May 24, 2013
https://robertscribbler.wordpress.com/2013/05/24/greenland-melt-speeding-up-northern-hemisphere-snow-cover-falling-below-average/
Blocking Patterns: Cool Air Down South Means a Heatwave in Greenland
Global warming has mangled the Northern hemisphere’s weather. No clearer indication of this is the fact that currently, where I’m sitting in Gaithersburg, MD it’s 48 degrees Fahrenheit. Now let’s jump northward. Way north. North of the Arctic Circle north. So far north that only tens of miles away rests a glacier hundreds of meters thick.
That’s right, we’re talking about Greenland. Nuuk, Greenland to be specific. What’s the temperature there currently at 3:51 PM, Gaithersburg time?
48 degrees Fahrenheit.
The fact that two places separated so far north and south can experience practically the same weather is a perfect illustration of what global warming combined with Arctic sea ice melt has done to our weather patterns. Currently, a powerful blocking pattern and a very wavy jet stream is plunging far to the south and into the eastern United States. That jet stream has origins in the Arctic, so it is currently involved in cooling down Gaithersburg, Maryland.
The jet currently running down over the eastern US drinks deep of warmer temperate and tropical air before making a hairpin turn to the north, it travels up over the Atlantic Ocean, keeps making its way north until, at last, it comes to Greenland, depositing 48 degree Gaitherburg air directly over where it should be freezing in Nuuk.
That 48 degree temperature is a veritable heatwave for Nuuk at this time of year. The average daily high for this date is 26 degrees Fahrenheit. Nuuk’s high for today is 22 degrees warmer than it should be. And it’s not just today. For much of the winter Greenland has been far, far hotter than usual. The below graph, provided by NSIDC shows average temperatures for the Nuuk region of Greenland being about 5 degrees Fahrenheit or 3.3 degrees Celsius above average for the entire period.
(Image source: NSIDC)
Persistent warmer temperatures for Greenland have been a typical result of the new, global warming spawned weather pattern. It is this weather pattern that resulted in a major melt event for Greenland last summer. One that wrecked infrastructure there and contributed mightily to a 1 cm rise in sea level in just one year. Well, that blocking pattern is still in place. Going into the spring/summer of 2013, the weather is still stuck in a much hotter than usual mode for Greenland. If it continues, it will likely mean both more glacial melt and more extreme weather.
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Posted by robertscribbler on April 3, 2013
https://robertscribbler.wordpress.com/2013/04/03/blocking-patterns-cool-air-down-south-means-a-heatwave-in-greenland/
Greenland Melting in January, February and March
(Early March Melt in Greenland. Image Credit: NSIDC.)
Normally melt doesn’t begin in Greenland until May. But, this year, Greenland saw melt in the midst of winter.
According to reports from the National Snow and Ice Data Center, sections of the southeast coast of Greenland melted throughout January, February and March of 2013. This level of melt is far above average and almost never appears so early.
Even more disturbing is the fact that some areas of Greenland have melted for more than 50 days so far this year (out of 70 total). So, in some locations, Greenland has seen melt for almost all days of 2013. And it isn’t even spring.
The above image provided by NSIDC shows the number of melt days for Greenland so far this year. Note the southeast coast where melt has already occurred between 10 to 50+ days out of 70 so far this year.
Winter is a time when cold temperatures should keep the Greenland glacier from melt and loss of mass. When the great ice sheets should rebuild before summer. However, this is not happening. Instead, melt which would normally appear in May continues in some regions throughout winter. What this would seem to indicate is that the heat absorbed by the glaciers during summer and the warm surrounding oceans carry enough energy to continue melting the ice sheets throughout the long dark of the Greenland winter.
Taking into account the very thin and cracking Arctic sea ice, Greenland melt throughout winter is but one more unprecedented set of events for the very odd Arctic winter of 2013. And, given the new trends, one has to wonder if year-round melting of Greenland will become a regular occurrence.
The above image shows melt for 2013 (red) in comparison with normal melt (blue). Note the various spikes in melt days beginning in January, ramping up in February to near end-May values which fall off and then appear again in March.
It is also worth noting that last year showed Greenland melting over nearly 100% of its surface at the height of summer. With a normal year showing a 25-30% surface melt for Greenland, it appears that a period of historic and unprecedented melt is rapidly taking hold.
Links:
http://nsidc.org/greenland-today/
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Posted by robertscribbler on March 11, 2013
https://robertscribbler.wordpress.com/2013/03/11/greenland-showing-melt-in-february-and-march/
Total Meltdown Warning: High Risk Arctic Summer Sea Ice Will Completely Collapse by 2013-2017
This winter, massive cracks riddled the sea ice. Forming over an ice sheet nearly 80 percent thinner than in 1980, these cracks appeared suddenly and grew with astonishing speed. Covering hundreds of miles in minutes, they laid bare the ocean beneath, venting heat into an already quickening atmosphere (read more about the crack-up here).
2012 was the hottest La Nina year on record and the 9th hottest year on record globally. It was a year that saw a massive collapse in summer Arctic sea ice continue with a vengeance. Sea ice volume, as measured by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) fell to 3,264 cubic kilometers by September of 2012. This was 750 cubic kilometers below 2011’s record low and 3,200 cubic kilometers below 2007’s record low.
(Image credit: PIOMAS)
Even more disturbing is the fact that from the period of 2005 to 2012, two large, precipitous drops in sea ice volume occurred. In 2010, 2460 cubic kilometers of sea ice volume was lost. And in 2007, 3440 cubic kilometers of sea ice volume faded into the ocean.
With minimum sea ice volume for 2012 now sitting at 3264 cubic kilometers, a single melt year with weather conditions like 2007 would bring the total down to zero volume by end of summer 2013. This event may be unlikely to happen. But there is still a significant risk, a 10% potential, that something on this order may happen in 2013. Based on past sea ice losses and a current, ongoing melt trend, we can’t rule it out. So for the first time ever in the modern record, there is a chance that summer sea ice will completely disappear this year.
But even if we saw a repeat of 2010’s massive melt, volumes would be pushed very low — down to a paltry 800 cubic kilometers. And, in such a case, a complete melt by 2014 or 2015 becomes almost certain.
Taking into account the average rate of melt from 2005-2012, we see losses of 740 cubic kilometers per year. If these average losses continue through 2013-2017 total melt occurs sometime in the summer of 2017. But any catastrophic melt similar to 2007 results in a complete melt during any one of these five years.
Even if melt is ‘mild’ compared to averages over the past 8 years, it is almost certain that all summer sea ice will be gone by 2020. For these reasons, it is very important to sound the alarm for total summer sea ice collapse now. Given current trends, it appears less likely that summer sea ice will remain and more likely that the world will see an open Arctic Ocean sometime within the next five years and, almost certainly, by the end of this decade.
Looking at the risk trends, it appears 10% likely that zero summer sea ice volume will be reached by the end of 2013. That likelihood jumps to 25% by the end of summer 2014. By 2015, if current trends bear out, the chance is around 40%. Moving on to 2016, we get into the range of higher probabilities with a 50% likelihood of total summer melt. And without some kind of negative feedback or the intervention of weather less favorable for melt, there is more than a 60% likelihood that all sea ice will have disappeared by summer of 2017 (These probabilities are based on trends analysis and are not based on any official climate model).
Feedbacks To Play a Role?
There are a number of feedbacks taking place in the Arctic that may play a role in either preserving a small remnant of summer sea ice or in hastening the ice sheet’s eventual collapse. Some of these feedbacks are visible now. But there are, likely, others that have not yet been identified. Here are a few of the major players:
The first is sea ice melt itself. As sea ice melts more of the white, reflective ice is replaced by dark, heat absorbing, water. As less and less of the Arctic Ocean is covered by ice during the summer months, more and more dark ocean is available to absorb the near-constant summer sun’s rays. This feedback, called loss of albedo, would push for a faster melt and, if it comes to dominate, would result in a more rapid melt of far more fragile ice.
Fragile ice. As sea ice becomes thinner it is subject to an increasing array of mechanical forces that may hasten its break-up. Thin ice is less resilient to storms, for example. And as the ice breaks into smaller and smaller chunks a greater portion of its surface area is exposed to the sun’s rays and to the surrounding, warmer water. Again, this feedback would push for a more rapid melt.
Methane and CO2 release. Large portions of the frozen land-mass called permafrost are melting in the Arctic. When the organic matter in the permafrost breaks down either methane or CO2 is released. In addition, large volumes of methane are bubbling up from the sea-bed both from freed methane hydrates and from submerged and thawing permafrost. These releases produce local spikes of the greenhouse gasses methane and carbon dioxide while also amplifying global, human-caused climate change. Methane release local to the Arctic tends to increase Arctic heat trapping, resulting in more rapid ice melt.
Greenland melt. Over the past few years, an ever-increasing volume of cold, fresh water has been melting from the vast glaciers of Greenland. Ironically, this cold water melt may produce one of the the few negative feedbacks in the Arctic environment. Cold water flushing into the Arctic Ocean and North Atlantic may perturb heat transport to the Arctic via the Gulf Stream. Large volumes of fresh water also freeze at higher temperatures than the saltier ocean water, potentially restoring some albedo to the Arctic. So, in this case, large pulses of water from Greenland may result in a small volume of ice remaining to the north of Greenland during late summer. Even larger pulses may result in some recovery of the ice pack. But such an event would come at the cost of rapidly rising seas, powerful storms, and dangerous, large water pulses from Greenland. The question in such a case is if the positive human forcing on the climate system and the strength of other amplifying feedbacks in the Arctic is enough to overwhelm the negative feedback of water pulses from Greenland.
Because it appears less likely that water pulses from Greenland will grow large enough to produce a powerful enough negative feedback to overwhelm summer ice melt short-term, it appears that complete summer ice melt by 2013-2017 is a high risk and total ice melt by 2020 is almost certain.
After that time, all eyes turn to Greenland as the great ice sheets begin to play their role in re-establishing equilibrium to the Arctic environment. The surrounding heat of the oceans, air, and the amplifying feedbacks coming from the Arctic environment itself will almost certainly push Greenland into a very rapid melt phase by the late 2010s onward. And this next phase of Arctic melt will be far more dangerous and troublesome than the rapid sea ice melt period of 1979-2020.
Cracks of Doom
In parting, I will leave you with this graphic provided by the US Navy. It shows a broad but very thin ice sheet covering much of the Arctic. It shows the remaining, small portion of thick ice hovering just north of the Arctic Archipelago and the north shore of Greenland. It shows how much of the thick sea ice has already been flushed out through the Fram Straight.
What it does not show are the cracks that appear, periodically, like Arctic lighting over the now fragile ice sheet.
This is the state in which the Arctic enters its 2013 melt season. Thin. Depleted. Fragile. And with the cracks of its eminent demise now riddling its surface.
(Image credit: US Navy)
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Posted by robertscribbler on March 7, 2013
https://robertscribbler.wordpress.com/2013/03/07/total-meltdown-high-risk-arctic-sea-ice-will-completely-melt-2013-2016/
Greenland Glacial Melt Rapidly Increasing, So Why is Andrew Revkin Telling us No Policy Response Necessary?
In 1995, Greenland contributed no melt water to global sea level rise. By 2012, melt had increased rapidly to more than 7 mm. By comparison, Antarctica contributed about 4 mm by 2012. Ever since 2003, melt rate growth from Greenland has outpaced that of Antarctica.
In total, Greenland contains enough ice to increase world sea levels by about 6 meters or 20 feet. Quite a lot of water. By comparison, West Antarctica, which is most likely to melt alongside Greenland due to human-caused global warming, contains enough ice to raise sea levels by about 5 meters (16.5 feet). The last time greenhouse gasses were as high as they are today, both these ice stores melted. Along with thermal expansion of water and additional contributions from mountain glaciers and other parts of Antarctica, total sea level rise at around 400 ppm CO2 was about 75 feet.
As the globe warms due to human-caused climate change, we can expect increasing outflows of water from both Greenland and West Antarctica. To prevent such changes, at the very least, will require serious improvements to world energy and climate policy. And so monitoring ice melt in these regions cannot be entirely divorced from the need for such policy if we are to maintain a world with stable coastlines, a world in which states and nations aren’t at risk of being wiped off the face of the Earth by rising waters.
So one wonders why Andrew Revkin recently made this statement in his dotEarth blog:
“The dramatic surface melting [in Greenland], while important to track and understand has little policy significance.”
Revkin’s statement has to do with a recent ice core sample study which found that, during the Eemian, the last inter-glacial period, Greenland melted ‘only’ enough to increase sea levels by 1-2 meters. The study did not conclude, as Revkin did, that Greenland ice melt caused by increases in greenhouse gas emissions would follow the same pattern as it did in the Eemian. Nor did it recommend, as Revkin did, divorcing policy from observations of increasing Greenland ice melt.
Revkin’s argument and assertions aren’t new. In fact, James Hansen in his most recent paper on Greenland and West Antarctic ice melt cautions that melt in Greenland is not likely to follow the same pattern as the Eemian and that inland glaciers aren’t so buttressed from ocean influence as some suppose. Even more disturbing is the fact that some climate change deniers tend to use the Eemian to support some of their own, non-scientific, arguments.
Professor Richard Alley, whom Revkin interviewed in his blog, had his own response to this point by Revkin:
“We have high confidence that warming will shrink Greenland, by enough to matter a lot to coastal planners.”
In other words, Greenland melt has serious policy implications for coastal planners (and many more people, for that matter). A recent report found that Miami may well not be a viable city before the end of this century and, possibly, before it is even half over. Much of south Florida and many low-lying regions of the world are likely to suffer similar fates.
In general, it is not a good idea to suppose that current melt trends will mirror those of the Eemian. Nor that melt will be as gradual as some expect. Nor that we should not base policy decisions on an observable and increasing danger of damaging sea level rise.
Links:
http://www.meltfactor.org/blog/?p=811
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Posted by robertscribbler on January 30, 2013
https://robertscribbler.wordpress.com/2013/01/30/greenland-glacial-melt-rapidly-increasing-so-why-is-andrew-revkin-telling-us-no-response-necessary/
Greenland Shows Strong, Intensifying Melt Trend Since 2000; 2012 to Break All Previous Records
(Image Credit: Marco Tedesco)
Over the past decade and a half, Greenland has shown a powerful trend toward increased melt. The image above, provided by Marco Tedesco, who recently released a report on 2012’s record Greenland melt, shows a stark trend of increased melt ending in the unprecedented melt season that occurred this year.
Note that the above graph only shows cumulative melt through August 8th of this year, so final melt index values are likely to be even higher.
From Tedesco’s “Greenland Melting” website:
“The melting index is computed from passive microwave satellite measurements and it can be seen as a measure of the ‘strength’ of the melting season: the higher the index the more melting occurred. With more melting yet to come during August, 2012 will position itself way above the old records, likely becoming the ‘Goliath’ of the melting years during the satellite record (1979 – to date).”
Overall, seasonal melt has been far above the average range with many areas experiencing melt for 50 days longer than the average season:
(Image credit: Marco Tedesco)
Cumulative mass loss is also running higher than previous record years with 2012 at 90 gigatons of mass lost through the end of July. The last record year, 2010 showed 60 gigatons of mass lost through the same period. August tends to show high mass loss rates and mass loss can continue through September, so we will have to wait for final values in these figures.
Other indicators of the resiliency of the Greenland Ice Sheet are also coming in. Jason Box tracks Greenland’s reflectivity (albedo) and has made some startling observations. You can see from the image below that the reflectivity of Greenland’s ice sheet has been far lower than any previous year in the record:
(Image credit: Jason Box)
Based on secondary observations, Jason has speculated that this is possibly the lowest reflectivity for Greenland since the Medieval Warm Period which peaked in 1150.
Reflectivity is important because it determines how much solar radiation the ice sheet absorbs. The more radiation absorbed, the greater the potential for melt.
In all, this has been a critical year for Greenland, and should ice melt trends continue within this range or increase, it will become increasingly clear that Greenland is encountering a melt tipping point.
Please help support our continuing efforts.
Links:
http://www.greenlandmelting.com/
http://www.meltfactor.org/blog/
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Posted by robertscribbler on August 16, 2012
https://robertscribbler.wordpress.com/2012/08/16/greenland-shows-strong-intensifying-melt-trend-since-2000-2012-to-break-all-previous-records/
Greenland Shatters Previous Melt Record Set in 2010; One Month of Melt Yet to Go
(Photo Credit: Marco Tedesco)
According to reports from Arctic researchers headed by Marco Tedesco, Greenland broke the melt record set in 2010 on August 8th of this year. With one month of melt still remaining, it appears that Greenland is now set to shatter all previous melt records since observations began 30 years ago.
This record melt coincided with the hottest summer Greenland has experienced in at least 123 years, the last time melting covered the entire ice sheet, as indicated by ice core data. It has also resulted in structural damage to parts of Greenland’s infrastructure.
“With more yet to come in August, this year’s overall melting will fall way above the old records. That’s a Goliath year — the greatest melt since satellite recording began in 1979,” noted researcher Marco Tedesco, assistant professor of Earth and atmospheric sciences from The City College of New York.
Tedesco and his fellow researchers made use of an array of microwave sensors aboard a US Air Force Satellite system called the Defense Meteorological Satellite Program. These sensors tracked melt over the Greenland ice sheet and established enough data to conclude that 2012 melt had entered record territory by August 8th.
The data Tedesco produced showed extreme melting in every region of Greenland including the higher elevation areas to the north. In these higher elevation areas, melt generally only continues for a few days. This year, so far, melt in these areas has occurred for more than two months running.
“Part of the meltwater will refreeze and part of the meltwater will run off to create streams and eventually take off into the sea and contribute to sea-level rise or the hydrological cycle,” Tedesco said during an interview with the magazine LiveScience.
Melt water also tends to bore holes through the ice sheet, finding its way to the bottom where it serves as a lubricant that can speed the movement of glaciers heading to sea.
For much of this summer, Greenland has experienced long periods of record warmth. This has likely contributed to increased melt volumes and durations. In addition, sea ice, which tends to serve as an atmospheric insulator for the Greenland ice sheet has diminished to record lows for much of the summer. This one-two punch is having a severe impact on Greenland’s ice sheet and is likely a major contributor to the record melt we’ve seen this summer.
Please help support our continuing efforts.
Links:
http://www.livescience.com/22387-greenland-melting-breaks-record.html
http://www.huffingtonpost.com/2012/08/15/greenland-ice-sheet-melting_n_1783063.html#slide=1114410
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Posted by robertscribbler on August 15, 2012
https://robertscribbler.wordpress.com/2012/08/15/greenland-shatters-previous-melt-record-set-in-2010-one-month-of-melt-yet-to-go/
With One Month of Melt Remaining, Arctic Sea Ice Flirts With New Record Lows
Today Arctic sea ice area, according to Cryosphere Today, measured 3,097,000 square kilometers. This is about 30,000 square kilometers above the third and fourth lowest level ever recorded and about 105,000 square kilometers above the record lows for sea ice area set in 2007 and 2011. With one month of melt still remaining, we are currently well within striking distance of a new record low for sea ice area this year. And when one considers that over 140,000 square kilometers of sea ice was lost during one day of last week, any similar weather event would almost certainly put us into new record territory.
For the day, sea ice area is currently at an all-time record low.
Sea ice extent, though lagging sea ice area, is also currently in record low territory. The Japanese Space Agency (JAXA) is currently showing sea ice extent at 5,020,000 square kilometers, a record low for today and about 800,000 square kilometers above the record low set for 2007. The National Snow and Ice Data Center (NSIDC) is showing sea ice area measurements that are currently at all-time lows for the date and about 700,000 square kilometers above record low values set in 2007.
Most recent values for sea ice volume from the Polar Science Center (PIOMAS) show that we are also in record low territory there as well. And a new set of research by UK scientists has made similar findings to PIOMAS scientists, noting in a recent BBC report that the Arctic may experience ice free periods during summer in as little as 10 years.
Given these recent reports on record lows and potentials, it is worth noting that the vast majority of scientists very recently believed that the Arctic might experience ice free periods during summer as late as 100 years from now. Sea ice melt model runs indicated similar results. But observations of actual melt and response to business as usual global warming has resulted in a much more rapid melt than expected.
Arctic sea ice is a kind of canary in the coal mine for global warming. The reason is that sea ice has a powerful influence on global climate. First, it reflects sunlight away from the Earth, causing the Earth to absorb less radiation and, therefore, be quite a bit cooler. Second, darker water absorbs much more sunlight, so much so that researchers have found that open areas of water are as much as 5 degrees Celsius warmer than nearby waters covered in ice. Third, the Arctic Ocean and surrounding tundra, when exposed to higher temperatures, emit high volumes of methane gas. Methane is a powerful greenhouse gas that is at least 20 times as potent as CO2. And the Arctic contains enough of this methane to drastically increase human-caused global warming.
And then there is the issue of Greenland. Sea ice serves as a kind of insulator that protects Greenland from warm air to the south. With much of the sea ice gone for longer and longer periods, Greenland will be exposed to warmer winds from the south and from within the Arctic itself. Losing the sea ice is like Greenland losing its heat shield. So one can expect more rapid melting from Greenland as sea ice continues its decline. It is also worth noting that Greenland did not retain ice in the geological past when CO2 levels reached current levels near 400 ppm. And with Greenland’s ice melting, seas would rise by as much as 23 feet.
Current scientific estimates for sea level rise by the end of this century are in the range of 50 centimeters to 2 meters. The upper range of this estimate would have dramatic consequences for cities, regions, and nations around the world. But given the rapid rate of sea ice melt, these estimates could also be as far off as the previous estimates for sea ice melt were.
Please help support our continuing efforts.
Links:
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
http://arctic.atmos.uiuc.edu/cryosphere/
http://nsidc.org/arcticseaicenews/
http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/
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Posted by robertscribbler on August 15, 2012
https://robertscribbler.wordpress.com/2012/08/15/with-one-month-of-melt-remaining-arctic-sea-ice-flirts-with-new-record-lows/
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
Please help support our continuing efforts.
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Posted by robertscribbler on August 10, 2012
https://robertscribbler.wordpress.com/2012/08/10/video-of-greenland-ice-melt-washing-out-bridge-over-watson-river-2/
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