[joewp]

I was surprised we don't have a thread for Greenland. I think a lot of news and concern are going to be about that forsaken place over the next few years. To whit:

New Greenland Ice Melt Fuels Sea Level Rise Concerns

Stability in the rapidly changing Arctic is a rarity. Yet for years researchers believed the glaciers in the frigid northeast section of Greenland, which connect to the interior of the country’s massive ice sheet, were resilient to the effects of climate change that have affected so much of the Arctic.

But new data published Sunday in Nature Climate Change reveals that over the past decade, the region has started rapidly losing ice due to a rise in air and ocean temperatures caused in part by climate change. The increased melt raises grave concerns that sea level rise could accelerate even faster than projected, threatening even more coastal communities worldwide.

“North Greenland is very cold and dry, and believed to be a very stable area,” said Shfaqat Khan, a senior researcher at the Technical University of Denmark who led the new study. “It is surprisingly to see ice loss in one of the coldest regions on the planet.”

The stability of the region is particularly important because it has much deeper ties to the interior ice sheet than other glaciers on the island. If the entire ice sheet were to melt -- which would take thousands of years in most climate change scenarios -- sea levels would rise up to 23 feet, catastrophically altering coastlines around the world.

That's another tipped tipping point, as far as I'm concerned.

“These new measurements show that the sleeping giant is awakening and suggest -- given likely continued Arctic warming -- that it’s not going back to bed,” Box said in an email.

Yep, we've awaken a lot of sleeping giants.

[Tanada]

the-greenland-thread-merged-t8372.html
still here and going strong since 2005.

[joewp]

Oh well, ok. But that's in geopolitics, not environment. I don't think I've ever gone to that forum more than a handful of times.

[Graeme]

Some of the Greenland stories have been posted in the Arctic thread.

Regional warming triggers sustained mass loss in Northeast Greenland ice sheet

Northeast Greenland, where the glacier is found, is of particular interest as numerical model predictions have suggested there is no significant mass loss for this sector, leading to a probable underestimation of future global sea-level rise from the region.

An international team of scientists, including Professor Jonathan Bamber from the University of Bristol, studied the Northeast Greenland Ice Stream which extends more than 600 km into the interior of the ice sheet: much further than any other in Greenland.

Professor Bamber said: "The Greenland ice sheet has contributed more than any other ice mass to sea level rise over the last two decades and has the potential, if it were completely melted, to raise global sea level by more than seven metres.

"About half of the increased contribution of the ice sheet is due to the speed up of glaciers in the south and northwest. Until recently, Northeast Greenland has been relatively stable. This new study shows that is no longer the case."

The researchers analysed a large collection of historical aerial photography, radar measurements and satellite data that measure the surface elevation, ice speed and bed elevation of the Northeast Greenland Ice Stream.

They found that the glacier started to speed up and lose mass around 2003 as a consequence of a localised increase in temperatures. Their results also showed that mass loss has continued up to the most recent observations in 2012 despite regional temperatures falling back to more typical values.

Professor Bamber said: "Most projections of the future behaviour of the ice sheet have no, or little, contribution from this part of Greenland but these new results suggest that this region is sensitive to changes in climate and has the potential to contribute significantly now and in the future."

eurekalert

[dohboi]

Cool image of a glacier spilling into the sea at the main page of ClimateCentral where the article that joewp sited came from:

http://www.climatecentral.org/news/new- ... erns-17187

[rollin]

The unseen and mostly unspoken additional threat to the world is the gravitational anomaly disappearing. The Greenland ice cap pulls sea water to it through gravitational pull, making sea level about 350 feet higher at Greenland than 1700 miles away. This large pooling of water will diminish as the ice melts.

So in addition to sea level rise from added water volume, the redistribution of water could add several meters to sea rise in places far away from ice caps. Greenland and Iceland will experience a lowering of sea level, while Scotland would experience a null effect from the Greenland melt rise as the sea lowered due to gravitational changes. Much of Europe will see a diminished rise in sea level while far away places will have an increased sea level rise.
For every meter of sea level rise (global average) caused by Greenland melt, Greenland will experience a 2.5 meter lowering of sea level and places far away could experience up to 1.3 meters of sea level rise. Since the total ice sheet could cause an average of 7 meters rise, the far away places could experience a 10 meter rise in sea level just from Greenland.

Of course any melting in Antarctica has a similar effect. So basically the sea level rise is regional and uneven. Just to complicate it more the rebound from the previous ice age means northern regions are slowly rising and regions to the south of them are sinking (Chesapeake Bay Area for example). The land rise and fall is measured in millimeters a year, so it will be overcome by actual sea level changes in the near future as the melting and warming accelerates which is projected to hit a centimeter per year or more.

Strange things are happening in river deltas - from the article "Land subsidence at aquaculture facilities in the Yellow River delta, China" Geophysical Research Letters.

[1] Differential Interferometric Synthetic Aperture Radar is applied to the coast of the Yellow River delta (YRD) in China. Like many deltas, the coastline of the YRD is dominated by aquaculture. Advanced Land Observation Satellite Phased Array L-Band Synthetic Aperture Radar (SAR) and Envisat Advanced SAR data acquired between 2007 and 2011 show that subsidence rates are as high as 250 mm/y at aquaculture facilities, likely due to groundwater pumping. These rates exceed local and global average sea level rise by nearly 2 orders of magnitude and suggest that subsidence and associated relative sea level rise may present a significant hazard for Asian megadeltas.

Due to a variety of factors much of the east coast of the US is experiencing 3 to 4 times the global rate of sea level rise. Some is due to a slowing of the Gulf Stream allowing water back that is normally pulled away from the coast.

Of course the melting of the polar ice caps could take anywhere from several hundred years to several thousand. In the meantime, climate change and resource depletion will take the front pages - at least for the next decade or three. That is if they ever get on the front page or even page three.

[kiwichick]

@ rollin

won't the melt from antarctica even out this effect from greenland?

[Subjectivist]

Until 5 million years ago there was no permanent ice in Greenland but most of Antarctica was still 2 miles high with the east antarctic ice sheet. If all Anarctica melts everyone is going to have higher sea levels, but if its just Greenland Europe will be virtually unchanged. Even if its Greeland and West Antarctica some places will be only lightly effected, but the tropics will get the most effct no matter where it melts from.

[rollin]

@ rollin

won't the melt from antarctica even out this effect from greenland?

The places far away from Greenland (subtropical and tropical) will get rise from both ice caps gravity differential, lucky them. Depending upon how much melt occurs in Antarctica, the effect from gravity shifts from opposite poles will be mixed. Antarctica has the ability to overwhelm the whole system due to the tremendous mass of it's ice cap. So in the worst case scenario, Greenland sea level would drop very little or maybe rise slightly, while the tropical and subtropical regions experience over 200 feet of rise.

Of course timing is everything, if Greenland ice cap self-destructs quickly the two effects could be well separated in time. Thus Greenland sea level falling dramatically and later rising again as Antarctica melts. Still the middle regions will only get excess rise out of any scenario.


There is still a lot of conjecture about how much and when the Antarctic ice cap will melt. A bit beyond our current knowledge, though we are sure more of it will go. A lot depends on ocean currents.

[Graeme]

How US Heat Waves Melted Greenland's Ice

In a reversal of this year's extraordinary winter weather, Greenland suffered the wrath of North America's epic heat waves in 1889 and 2012, a new study reveals.

"Last winter in the eastern United States, people associated the cold with the behavior of the polar vortex," said lead study author William Neff, a fellow at the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado, Boulder. "In fact the polar vortex can show two faces: a cold one or a warm one depending where you are. Last winter it showed its cold face to folks in the East. In the summer of 2012 it showed its warm face." [Video: 2 Extreme Melt Events 123 Years Apart]

Though more than a century apart, both massive surface melts were triggered by soaring temperatures east of the Rocky Mountains, according to findings published yesterday (April 24) in the Journal of Geophysical Research: Atmospheres. It turns out that North America's furnacelike heat was funneled toward Greenland by an atmospheric river, a narrow, fast-flowing current of moist, warm air, Neff and his co-authors found. A warmer-than-average ocean off Greenland moistened the scorching air as it blasted north.

discovery

[Tanada]

The way I understand it the only way to quickly melt even the surface of Greenland's Ice Sheet is for rain or dew from warmer zones to gather there. Water and water vapor carry a huge quantity of latent heat and melting ice absorbs a large quantity of latent heat to change phase from solid to liquid. Rain or dew carried by wind currents from warmer regions adds latent heat very quickly to ice and snow. If you have ever seen a huge snow pile on the edge of a parking lot the day before and the day after a thunderstorm you know what I am talking about. The same thing happens on Greenland or any other glacier/ice sheet. Fog is even worse than rain because fog is dew, a supply of water vapor condensing directly onto the snow/ice so it has even more latent heat than raindrops do.

When that warm humid air from the south extended over Greenland in 2012 the humidity condensed out onto the snow and ice as dew drops delivering latent heat directly to the surface, and as the dew gathered into droplets and the surface melted trickles, streams and rivers formed flowing into melt ponds that drained into the ice sheet carrying that heat deep into the glacier mass and warming it up inside. Just the change in position, the drop from 2 km up on the surface to the bottom of the ice sheet, released even more latent energy of position and melting ice inside the sheet. Basically for a brief period the ice sheet resembled Swiss cheese with thousands of ice caves carrying water to the bottom. After the even ended the ice caverns naturally closed as the weight of the ice compressed them together again, but all the ice mass that was in those tunnels that melted away is gone for good, it drained out to the sea from under the ice.

Glaciologists have actually done experiments where they have used water or steam hoses to create artificial ice caves at the bedrock level of glaciers to study what would happen. Ice is a very plastic material so once they stop melting the cave it starts shrinking as the ice deforms to refill the open spaces. The same thing happens under Greenland once the melting event ends, the weight of the ice compresses the remaining ice to fill up all those voids. Every time a melting event creates moulins and deep caverns it is a fresh event, while some of the surface features will remain anything much more than 100 feet down will collapse into solid ice over time, and the deeper it is the faster it closes together.

[joewp]

Greenland may lose more ice than expected | Ars Technica

The result is a much higher-resolution look at the valleys through which Greenland’s outlet glaciers flow, with depths calculated every 150 meters. Many are much deeper than we thought—mainly the valleys through which ice flows the fastest. That’s no coincidence, as they’ve been deepened by glacial erosion. While the deepest valleys account for only eight percent of the total length of the mapped valleys, about 88 percent of the ice flowing toward the sea passes through them.

Critically, many sit below sea level for significant distances inland. (See the blue areas in the image below.)

The deep nature of these valleys is important because many of the outlet glaciers currently retreating are being melted by warmer ocean water. Using our previous best guesses at Greenland’s topography, ice sheet models simulate a slowing of that retreat as the glaciers pull back to higher ground, decreasing contact with this warm water. That limits the amount of simulated ice loss. The new map, however, shows that many of these major outlet glaciers will have to retreat much farther inland to escape the ocean’s influence.

So another place the models underestimate the effects of warming. It keep seeming that things are going to happen a lot faster than most are predicting, especially the IPCC. One meter SLR by 2050 might just be possible, if not likely at this rate.

[joewp]

Study: climate change, fires melted Greenland ice surface

The findings suggest that continued climate change will result in nearly annual widespread melting of the ice sheet's surface by the year 2100. Melting in the dry snow region does not contribute to sea level rise. Instead, the meltwater percolates into the snowpack and refreezes, leaving a less reflective surface. This reformed surface becomes even more susceptible to future melting due to the surface's reduced reflectance. The ability to reflect sunlight is known as "albedo."

The study, conducted by Thayer School of Engineering and the Desert Research Institute, is reported in the Proceedings of the National Academy of Sciences. The research was supported by the National Science Foundation and NASA.

Stories about the Dartmouth study have appeared in a number of media outlets, including LiveScience, Smithsonian Magazine, The New York Times, Science News, and the Alaska Dispatch.

"The widespread melting of the Greenland ice sheet required the combination of both of these effects – a lowered snow albedo from ash and unusually warm temperatures – to push the ice sheet over the threshold," says Kaitlin Keegan, the study's lead author and a Dartmouth doctoral student. "With both the frequency of forest fires and warmer temperatures predicted to increase with climate change, widespread melt events are likely to happen much more frequently in the future."

I have to ask, can't some of that surface melt water leak down to that large bowl in the graphic in the above post and perhaps eventually lubricate and lift the ice mass in the middle, applying stress fractures to it, making it more susceptible to melting, as the higher temperatures and soot do, Making it melt into the ocean even faster?

What are the conditions under the ice sheet? Is there the possibility of liquid water there now, being that the crust is depressed several hundred meters and closer to the mantle and possible warm enough to keep water from freezing?

Should we all sell our beach houses?

[Subjectivist]

Study: climate change, fires melted Greenland ice surface

The findings suggest that continued climate change will result in nearly annual widespread melting of the ice sheet's surface by the year 2100. Melting in the dry snow region does not contribute to sea level rise. Instead, the meltwater percolates into the snowpack and refreezes, leaving a less reflective surface. This reformed surface becomes even more susceptible to future melting due to the surface's reduced reflectance. The ability to reflect sunlight is known as "albedo."

The study, conducted by Thayer School of Engineering and the Desert Research Institute, is reported in the Proceedings of the National Academy of Sciences. The research was supported by the National Science Foundation and NASA.

Stories about the Dartmouth study have appeared in a number of media outlets, including LiveScience, Smithsonian Magazine, The New York Times, Science News, and the Alaska Dispatch.

"The widespread melting of the Greenland ice sheet required the combination of both of these effects – a lowered snow albedo from ash and unusually warm temperatures – to push the ice sheet over the threshold," says Kaitlin Keegan, the study's lead author and a Dartmouth doctoral student. "With both the frequency of forest fires and warmer temperatures predicted to increase with climate change, widespread melt events are likely to happen much more frequently in the future."

I have to ask, can't some of that surface melt water leak down to that large bowl in the graphic in the above post and perhaps eventually lubricate and lift the ice mass in the middle, applying stress fractures to it, making it more susceptible to melting, as the higher temperatures and soot do, Making it melt into the ocean even faster?

What are the conditions under the ice sheet? Is there the possibility of liquid water there now, being that the crust is depressed several hundred meters and closer to the mantle and possible warm enough to keep water from freezing?

Should we all sell our beach houses?

If I recall correctly the Russian Antarctic project discovered a subglacial lake under the ice sheet the size of Lake Ontario. For a while they were afraid to drill all he way into it because he microbial life in it is expected to be unique having been isolated for millions of years.

No reason to think the same thing can't have happened in Greenland.

[KaiserJeep]

If I recall correctly the Russian Antarctic project discovered a subglacial lake under the ice sheet the size of Lake Ontario. For a while they were afraid to drill all he way into it because he microbial life in it is expected to be unique having been isolated for millions of years.

No reason to think the same thing can't have happened in Greenland.

You know what's really under the ice, don't you?



...and he's going to be really cranky after being awakened, look out Tokyo!

[Tanada]

A nice review of what melted and what accumulated in 2013 vs 2011 and 2012 can be found
http://neven1.typepad.com/blog/2014/05/ ... eview.html

Quite interesting, we are still in the period when local weather effects are more significant than hemisphere level climate effects. Last year in Greenland was very typical of the 1981-2010 pattern, this year could be the same showing a reversion to the prior weather system dominance. On the other hand this year could show similarity to 2011 and 2012 indicating a new weather system type is gaining influence on Greenland.

[dohboi]

More on weird structures below the ice: http://www.theguardian.com/environment/ ... -ice-sheet

[vtsnowedin]

More on weird structures below the ice: http://www.theguardian.com/environment/ ... -ice-sheet

Two quotes from the paper.

The melting and re-freezing at the bottom of the ice sheet has been underway for hundreds of thousands of years.

And

but Tinto said further study was needed.

Ok so they just discovered something new. that does not mean it is new, just we didn't know it before. and more research is needed is the constant lament of all grad students and post docs. As desperate as they are for continued funding you would think that they could think of some other way to get that point across. Just once I would like to see a conclusion that said we have exhausted all avenues of research on this subject and
find that there is no potential for further progress in this direction. We are moving on to other things among them are etc. etc.

[dohboi]

2012 Record Challenged as 40% of Greenland Ice Sheet Surface Melts on June 17th

Yesterday, 40% of the surface of Greenland melted.

It was still mid-June, yet a month before melt values typically peak. But a persistent high pressure system over Greenland, a rapidly melting Baffin Bay and warm winds riding up the west coast were enough to spur a surface melting event that shoved melt coverage firmly above the two standard deviation threshold and into record range.

http://robertscribbler.wordpress.com/20 ... june-17th/

[Tanada]

If we follow the 2012 pattern of weather over Greenland how many will be convinced it is an existential threat and not just media hype of an event that takes place ever 150 years or so. I heard that repeated a lot in 2012 when we had massive melting in Greenland just two years ago.

It would be nice if that graph showed the line for 2012 as well but I guess you can't have everything.