Showing posts with label Greenland. Show all posts
Showing posts with label Greenland. Show all posts

Thursday, November 21, 2013

High Methane Levels all over Arctic Ocean

High levels of methane were recorded all over the Arctic Ocean on November 19, 2013, as illustrated by the image below. The image also shows that most methane was present over the fault line that crosses the Arctic Ocean (as also indicated on the inset).

[ Click on image to enlarge ]
A recent post described that more methane may actually be present closer to the North Pole than IASA images may indicate. This because measurements can be obscured by clouds. If no data are recorded over a certain area, no methane levels will show up on images for the respective area. This was the case on November 17, 2013, when the Arctic Ocean was quite cloudy, and little or no data were recorded for the center of the Arctic Ocean.

On November 19, 2013, the sky was much clearer, resulting in a lot of data from the center of the Arctic Ocean, as also illustrated by the image below.

In conclusion, high methane levels can actually be present all over the Arctic Ocean, even when images only show high levels in some areas.

An earlier post described how the sea ice can act as a shield, especially when the ice is more than one meter thick.

How does this rhyme with the above image? The November 19, 2013, Naval Research Laboratory image on the right shows that the sea ice was meters thick in some locations where methane shows up on the top image.

So, is methane actually rising from the seafloor of the entire Arctic Ocean, perforating even the thickest ice and entering the atmosphere all across the Arctic Ocean? Or, if thick sea ice does act as a shield, how did methane appear all over the Artic Ocean in such huge quantities?

The images on the right indicate that the methane may actually only rise from the seafloor in a few locations.

As the top image on the right says, the Coriolis Effect can make methane over the Laptev Sea end up over Canada a few days later. So, methane may not be perforating the sea ice in the north of Canada, but may instead originate from elsewhere in the Arctic.

The animation underneath shows methane readings from November 9 to 19, 2013, with each of the 20 frames covering a period of 24 hours and with frames following each other up 12 hours after each other. As the animation shows, it looks like methane is predominantly entering the atmosphere at specific locations, most notably along the fault line that crosses the Arctic Ocean.

It may well be that this methane ends up all the way in Baffin Bay, to the left of Greenland. Since the Greenland ice sheet is 3 kilometers (1.9 miles) thick, this may form a natural barrier that keeps the methane there, also helped by winds rising vertically from Baffin Bay to well above Greenland's mountains. Methane may also be traveling under the sea ice, all the way from the Gakkel Ridge and the Laptev Sea right to Baffin Bay.

On the other hand, it could also be that hydrates underneath the sea bed of Baffin Bay itself have become destabilized and that, since the ice over Baffin Bay is rather thin, methane has no problem perforating the ice and is entering the atmosphere there in huge quantities.

Either way, the end-conclusion is that the methane that is now showing up all over the Arctic Ocean, is rising from the seafloor, due to destabilization of sediments that hold huge amounts of methane in the form of free gas and hydrates. As warming in the Arctic continues to accelerate, the danger is that this will cause more methane to rise from the seafloor and that the methane itself will contribute to warming in the Arctic, in a deadly spiral set to cause abrupt climate change at a devastating scale.



Saturday, November 16, 2013

More Methane as Sea Ice thins

The image below shows methane readings of 1950 ppb and higher, as at November 15, 2013, p.m., close to sea level. The image also shows sea ice concentration, as at November 7, 2013, i.e. the most recent SSMIS data available on methanetracker.

[ click on image to enlarge ]
The image shows huge amounts of methane rising from the seafloor along the fault line that crosses the Arctic Ocean. The image also shows huge amounts of methane over thinner parts of the sea ice. To illustrate this further, the November 15, 2013, Naval Research Laboratory image is added below, showing ice thickness based on the most recent sea ice data.


The image below zooms in on the large amounts of methane, stretching out all the way from the Beaufort Sea to Baffin Bay.

[ click on image to enlarge ]
Above image illustrates that methane does show up prominently where the sea ice is thin, confirming earlier conclusions that the sea ice acts as a shield, a seal if you like, holding the methane in place and thus giving microbes the time needed to decompose the methane while it is held underneath the ice.

This spells bad news, because it implies that, as the sea ice thins, more methane will be able to enter the atmosphere and contribute to warming that is already accelerating in the Arctic.

As discussed in a recent post, methane is rising from the seafloor of the Arctic Ocean due to destabilization of sediments that hold huge amounts of methane in the form of free gas and hydrates. This destabilization is in part due to warm water flowing in the Arctic Ocean along the Gulf Stream. Record warm water was present off the coast of North America in July 2013, and this warm water took some time to reach the Arctic Ocean, as shown on the image below, from that earlier post.


Water in the currents that are returning water to the Atlantic Ocean north of Canada is typically cold, as indicated by the blue color on the image below. So, while it is possible that the water was still sufficiently warm to cause methane releases from the seabed in the Beafort Sea and in Baffin Bay, in the northern parts of Canada, it seems more likely that the methane originated from areas along the fault line that crosses the Arctic Ocean and that the methane traveled - underneath the sea ice - with these currents all the way to the edges of the sea ice where the ice is sufficiently fractured and thin to allow methane to rise to the surface.

Image credit: Jack Cook, Woods Hole Oceanographic Institute
This seems confirmed by recent sea surface temperature data, as pictured below.


As above image shows, sea surface temperature anomalies (in orange, red and brown) are still showing up prominently along many parts of the Gulf Stream, all the way into the Arctic Ocean, where anomalies of more than 8 degrees Celcius have been recorded for some time now. At the same time, colder water (in green and blue) is flowing back into the Atlantic Ocean from the Arctic Ocean, along the edges of Greenland and further south. Colder currents typically flow at greater depth, but the above image also shows colder waters emerging at sea surface level, especially in areas somewhat off the coasts of Newfoundland and Nova Scotia, effectively preventing some warm water from traveling along the Gulf Stream to the Arctic Ocean.

Why are the currents that are flowing out of the Arctic Ocean into the Atlantic Ocean so strong at the moment? Powerful winds have speeded up these currents, as illustrated by the 30-days Naval Research Laboratory animation below, which also includes a 7-days forecast from November 15, 2013.


One of the feedbacks of accelerated warming in the Arctic is stronger winds and a huge amount of sea ice is currently flowing into the Atlantic Ocean, partly due to these strong winds. Similarly, the Naval Research Laboratory animation below shows huge amounts of sea ice, often very thick ice, being pushed into the Atlantic Ocean.



Last but not least, the youtube video below, Arctic Death Spiral and the Methane Time Bomb, shows some of the most powerful video footage on climate change, highlighting the danger that methane will continue to rise from the seafloor of the Arctic Ocean in ever greater quantities, resulting in a wipe-out of civilization, extinctions at massive scale and devastation of the planet as we know it.





 

Sunday, August 11, 2013

Dramatic rise in methane levels since end July 2013

There has been a dramatic rise in methane levels since end July 2013. The image below pictures methane levels above 1950 ppb on the Northern Hemisphere from 12 p.m. August 9, 2013, to 12 a.m. August 10, 2013.


[ click on image to enlarge ]
Quite suddenly, readings above 1950 ppb have become commonplace since July 31, 2013.


The chart below illustrates the dramatic jump in methane levels that occurred since July 31, 2013. The chart shows the area (square km) with methane readings over 1950 ppb for selected layers, over the period from July 24, 2013, to August 9, 2013. The chart further below shows that peak methane levels have increased dramatically.

Particularly worrying are high levels of methane over the Arctic Ocean, such as on the image below showing methane levels over 1950 ppb in yellow for selected layers on August 5, 2013 (a.m.).
[ click on image to enlarge ]
Methane levels are also very high on the Southern Hemisphere, as illustrated by the image below on the right. High readings have featured over the heights of Antarctica for quite some time, but the high levels of methane over the oceans on the Southern Hemisphere have only shown up recently. They could be caused by one or more methane hydrates getting destabilized in the ocean between Antarctica and South America.
[ click on image to enlarge ]
Peter Carter sent the image below, edited from NOAA Earth System Research Laboratory, showing high (and rising) methane levels in Pallas Sammaltunturi (north Scandinavia), measured with surface flasks.

Peter also added the image below, pointing at high methane levels in Lac La Biche, Northern Alberta, Canada. What to make of it?, Peter adds, It is not far from the Tar Sands - that does have a methane problem, but it is basically wetland peat region vicinity which is why I checked it.

Monday, March 18, 2013

Huge patches of warm air over the Arctic

Over the past month or so, huge patches with temperature anomalies of over 20 degrees Celsius have been forming over the Arctic.

The three images below show such patches stretch out from Svalbard to Novaya Zemlya (top), north of Eastern Siberia (middle) and over West Greenland and Baffin Bay (bottom).




How these patches with warm air developed is further illustrated by the animation below, which goes from February 12, 2013, to March 18, 2013.

Thursday, February 7, 2013

Arctic Sea ice Volume and Greenland Melt Update

Arctic Sea Ice Volume

The image below, from the ArctischePinguin site, shows the current volume of Arctic sea ice, updated with PIOMAS data from the Polar Science Center of the University of Washington.
As the above image shows, a minimum volume of 3000 cubic km is expected to be reached in September 2013 (red dotted line), with a margin of error that allows for the sea ice to disappear altogether in a few months time.

The image below updates the exponential trends for each month.

Greenland Melt

Meanwhile, the National Snow and Ice and Data Center (NSIDC) has started a page with daily updates of the extent of the Greenland melt. The image below pictures the Greenland melt in 2012 on the left, and the situation up to February 6, 2013 on the right.


Thursday, January 10, 2013

Dark Snow Project - Research into soot on Greenland

Fossil fuel combustion creates carbon emissions that increase atmospheric thickness, warming climate. The occurrence of wildfire increases with climate warming, increasing soot loading of the atmosphere. Some of this soot is transported through the atmosphere and is deposited on glaciers, lowering their reflectivity, increasing solar energy absorption, increasing melt rates.
image from DarkSnowProject.org

In parts of Greenland where winter snow loss during each melt season exposes impurity-rich bare ice, the surface reflectivity drops from 85% to 30%. Consequently, most of the 24-hour sunlight goes into ice melt. In this Dark Zone, the impact of soot manifests strongest in a self-reinforcing feedback loop that research by Jason Box has shown to have doubled melt rates in the past decade.

High on the inland ice sheet where melting is rare, satellite data show surface darkening making the researchers suspect that wildfire and industrial soot are to blame. Darkening here promotes snowpack heating, bringing earlier melt, keeping melt going longer. Here is where this feedback is changing the ice sheet in surprising ways, leading to complete surface melting in year 2012.



To measure the extent to which soot particles enhance melting, Jason Box is organizing a Greenland ice sheet expedition for 2013. The Dark Snow Project expedition is to be the first of its kind, made possible by crowd-source funding.



References

Fire and Ice: Wildfires Darkening Greenland Snowpack, Increasing Melting (News Release from Byrd Polar Center)
http://bprc.osu.edu/~jbox/DS/20121205_news_release_CALIPSO_etc.pdf

- The DarkSnowProject
http://darksnowproject.org

-Video: Sampling Greenland, the Dark Snow Project, by Peter Sinclair, produced at Greenman Studio, Midland, MI.
http://www.youtube.com/watch?v=vT6H7HPWkqU

- Where there’s fire there’s smoke - Blog by Jason Box, the Meltfactor.org


Further reading

- Greenland is melting at incredible rate
http://arctic-news.blogspot.com/2012/07/greenland-is-melting-at-incredible-rate.html

Friday, October 26, 2012

Big changes in Arctic within years

Above interactive graphic illustrates the decline of the annual sea ice minimum volume in the Arctic over the years.

What trend can best be fitted to these data? Below, I've added a trendline that I believe best fits the data, but I encourage others to come up with better trends.


The trend points at 2014 as the year when Arctic sea ice will first reach zero volume for some time during that year. As discussed in the earlier post Getting the Picture, the Arctic Ocean looks set to be ice-free for a period of at least three months in 2015 (August, September and October), and for a period of at least 6 months from the year 2020 (June through to November).

Natural variability and strong feedbacks may speed things up further. Decline of sea ice in 2012 was such that we can expect a very low volume in December 2012, which could lead to inclusion of December in the period projected to be ice-free from 2020. That would make the ice-free period seven month long, i.e. well over half a year.

The image below shows the three areas where albedo change will be felt most in the Arctic, i.e. sea ice loss, decline of albedo in Greenland and more early and extensive retreat of snow and ice cover in other areas in the Arctic.


Related

- Getting the Picture
arctic-news.blogspot.com/2012/08/getting-the-picture.html

- Albedo change in the Arctic
arctic-news.blogspot.com/2012/07/albedo-change-in-arctic.html

- Greenland is melting at incredible rate
arctic-news.blogspot.com/2012/07/greenland-is-melting-at-incredible-rate.html

- Albedo change in the Arctic threatens to cause runaway global warming

Amplification of climate change in the Arctic

In contrast to multi-year old ice, first-year old ice—ice that formed only since the last melt season—is thinner, saltier, and much more prone to melt.


Over the years, the loss of sea ice has become especially manifest in the older ice, as illustrated by the image below.


Salt content and hardness play a part in multi-year ice’s resistance to melt, explains a recent NOAA article, but the main characteristic that allows the ice to survive the melt season is thickness.

Screenshots from: PIOMAS Arctic Sea Ice Thickness Simulation 1978-2011
The decline in thickness over the years goes a long way to explain the self-reinforcing character of sea ice decline in the Arctic.

As another recent NOAA article describes, there is “something extra” behind the record ice retreats of the past 6 years: each June, the prevailing winds shifted from their normal west-to-east direction and instead blew strongly from the south across the Bering and Chuchki Seas (left on the image below), over the North Pole, and out toward Fram Strait. (The length of the lines is qualitative: longer lines mean stronger winds.)

Average June wind vectors in 2007-2012 (orange) compared to 1981-2010 average (white) based on NCEP reanalysis data provided by Physical Sciences Division at NOAA ESRL. Map by Dan Pisut, NOAA Environmental Visualization Lab.

The image below shows the unusual air pressure patterns that gave rise to the wind shift. Air pressure across the Arctic in Junes from 2007-2012 was completely lopsided, with two pockets of higher-than-average pressure sprawled across the North American Arctic and Greenland. These areas of high pressure act like boulders in a river. They slow and disrupt the normal westerly flow of the wind, forcing it to make, large, meandering detours to the north or south.

Average geopotential height anomaly at 700 millibar pressure level in Junes from 2007-2012 compared to the long-term average (1981-2010) based on NCEP reanalysis data provided by PSD at NOAA ESRL. Orange colors are higher-than-average pressure; blue is lower-than-average pressure.     Map by Dan Pisut, NOAA Environmental Visualization Lab.
Arctic oceanographer and his NOAA colleagues think these “blocking highs” on the North American side of the Arctic created the unusually strong southerly flow that brought warm air into the central Arctic and over Greenland. The persistent southerly winds would help explain both the record low sea ice extent in summer 2012, as well as the island-wide melting of the surface of the Greenland Ice Sheet, which satellites detected in July 2012.

“This story started with us trying to figure out why the sea ice extents of the past 6 years or so have been so much lower than we would expect based on the long-term warming trend alone,” says Overland, “and we think this unusual circulation of the Arctic atmosphere is major part of it.”

Why, asks Overland, have these high pressure patterns have been forming so consistently each June for the past six years? The repeated appearance of these atmospheric features each June is so unusual that it’s the equivalent of a 1-in-a-1000 event. Can this be attributed to natural variability?

Instead, Overland’s hunch is that the cause is a change in the atmosphere that is itself connected to climate change in some way, possibly linked to record and near-record low June snow cover in the Canadian Arctic in recent years. “We don’t know that part of the story yet,” he says, “but this would certainly be the type of amplification of climate change [warming triggers changes that lead to more warming] we have been expecting to see in the Arctic.”

References

- Arctic Sea Ice Getting Thinner, Younger
http://www.climatewatch.noaa.gov/article/2012/arctic-sea-ice-getting-thinner-younger

- June wind shift a little something extra behind recent Arctic ice losses
http://www.climatewatch.noaa.gov/article/2012/june-wind-shift-a-little-something-extra-behind-recent-arctic-ice-losses

- Poles apart: A record-breaking summer and winter
http://nsidc.org/arcticseaicenews/2012/10/poles-apart-a-record-breaking-summer-and-winter/

- PIOMAS Arctic Sea Ice Thickness Simulation 1978-2011, published Sep 14, 2012 by ArctischePinguin
https://www.youtube.com/watch?v=G1TLzgSlGtQ

Related

- Arctic summer wind shift
http://arctic-news.blogspot.com/2012/10/arctic-summer-wind-shift.html

- The recent shift in early summer Arctic atmospheric circulation
http://www.agu.org/pubs/crossref/2012/2012GL053268.shtml

- Presentation by Dr. Jennifer Francis, Rutgers University
https://www.youtube.com/watch?v=RtRvcXUIyZg
http://marine.rutgers.edu/~francis/pres/Francis_Vavrus_2012GL051000_pub.pdf

Wednesday, September 12, 2012

Storm enters Arctic region

Tropical Storm Leslie hit Newfoundland on September 11, 2012. Leslie was discussed in the earlier post by Paul Beckwith. The NOAA image below gives a 5-day forecast of Leslie's continued path along the coasts of Greenland and Iceland.


That may keep Leslie just out of the Arctic Circle, but this path does make it enter the Arctic Region, i.e. the area where temperatures in the warmest month used to remain under 10°C, or 50°F, as illustrated by the map below.


The image below shows how Leslie's impact on air pressure. The image below is part of a series of images showing how Leslie causes a low pressure area (compressed isobars) that then propagates over the Arctic ocean region. See further images at the Polar Meteorology Group at Ohio State University.


This low pressure region can also be tracked in the 9-panel GFSx forecast below, from Unisys Weather.



Storms are important to the Arctic, they can cause high waves and changes in wave direction, as illustrated by the combined images below from OceanWeather Inc



Storms can cause decline of Arctic sea ice and bring warm water and air into the Arctic. The Diagram of Doom, discussed in more details in an earlier post, pictures ten feedbacks that can cause warming in the Arctic to accelerate. Storms are a factor in many of these feedbacks. 



As illustrated by the NOAA image below, accelerated warming results in high temperature anomalies, increasing the danger of methane releases from sediments under the water.


Paul Beckwith comments that in this case Greenland acts as a barrier to the storm entering the Arctic due to its 3 km ice cap (note also that the thickness of the troposphere is only about 7 km high in the Arctic, meaning that Greenland extends up in altitude to cover >40% of the atmosphere in which weather occurs). What this means is that the storm will be diverted from directly crossing Greenland.

Paul adds a warning: In this case we are lucky in that the storm passes below and to the right of Greenland and then heads past Iceland on its way to north of Scotland. A worse scenario for the Arctic and the sea ice there would be if the storm stalled of the western coast of Greenland and slowly tracked up north through the Davis Strait and across the Canadian archipelago and then directly into the Arctic to the west of Greenland. Such a storm would have devastating consequences to the Arctic and the sea ice (not to mention Greenland, mostly on the coasts). Lots of heat and moisture would be transferred into the Arctic by such a storm.

Saturday, August 25, 2012

Future of Arctic Ice: The Three Perspectives

By Veli Albert Kallio
Veli Albert Kallio in front of Peter Wadhams and John Nissen at
APPCCG event, March 13, 2012, House of Commons, London


I use three type sources to assess climate:
  1. the peer-reviewed literature and news reports; 
  2. the whistle-blower organisations (Wikileaks, Cialeaks that release data files from the US Army, Navy, Air Force, CIA, the US State Department, or intercepted corporate telephone or Internet communications; and 
  3. indigenous people’s organisations and their ethnoclimatology people.

June 26, 2012: the Cialeaks released data files from the US stating that the North Pole will be ice free in 2013. These appear to be submarine upward sonar readings of ice from the US Navy. These contrast strongly what NSIDC is saying about the sea ice surviving much longer. I do not know the reason why US Navy and NSIDC advice differently on this point (an exponential trend projection based on PIOMAS data gives zero-ice 2015).

As per the question, where all heat goes after the sea ice has melted, I stick to the advice given in the United Nations General Assembly motion 101292: the Polar Ice responds extremely fast: first the sea ice melts and disintegrates, then followed by intense methane surges and equally rapid losses of the Arctic terrestrial ice cover in Greenland which never melts, but collapses instead.

After the sea ice loss, the permafrost and Greenland Ice Sheet take up a large portion of that energy that was previously used to melt the sea ice during the short summers. As a result, the ocean warms up and rains much more water than now with the flash-floods becoming very frequent in Greenland. As a result many times more water appears on top of Greenland’s Ice Sheet.

Greenland Ice Sheet rapidly metamorphoses from a (cold, dry, stable) moraine-forming ice sheet into a (warm, wet, dynamic) aggregate-forming ice sheet as the water amount within ice sheet and at its base increase. The bottom part of the ice sheet turns increasingly into water-logged, “mushy” ice that loses its internal strength, while pot holes on bedrocks become filled by water.

By 2020's 1/3 of Greenland Ice Sheet's base (between ice and bedrock) is dotted with water ponds at which point the rapid erosion processes (cavitation, plucking and kolking) pulverise the ice so aggressively that an "ice sheet thrust" develops against coastal perimeter at Melville Bay area. Even the dry parts of ice sheet then no longer can hold the ice dome in place and Heindrich Ice Berg Calving Event (H-1) occurs.

After the Heindrich Minus One (H-1) event the North Atlantic Ocean between America and Europe fills by broken ice that triggers a near-instantaneous severe climate cooling: the Last Dryas. Europe will see many years lasting freeze with Dryas Octopetala rapidly taking hold across continent's then barren soils. The ice volume is 10 times less in Greenland than in a similar event when the Hudson Bay Ice Dome reminders collapsed.

This ice evolution history of the First Nations of Americas as expressed on the UN General Assembly motion 101292 and the Plantagon Declarations, were used on the global-warming themed film “A Day After Tomorrow” and also “2012” by director Roland Emmerlich. Unfortunately, the films assigned incorrect physics and caused great annoyance among the Native American Indian communities due to many other inaccuracies in details therein:

“2012” films ‘mystery radiation of sun’ was never caused by neutrinos, but methane: the Bøllinger Years. The ‘core melting’ was due to the displacement of asthenosphere’s fluids as the heavy Foxe-Laurentide Ice Dome destabilised forcing the liquid minerals in asthenosphere to move out of way, the pressures causing huge eruptions and lava floods (asthenosphere is like a “wet sponge”, a composite of solid and liquid minerals).

“A Day After Tomorrow’s freeze failed the Boyle’s Law: ultra-cold stratosphere cannot fall, and cause instantaneous sea level jump that was followed by the Younger Dryas freeze-up, but ice can.

The First Nations of Americas have raised the alarm very clearly continuously for the last 20 years since the first Rio de Janeiro summit in 1992 that the West is living in delusions (including its scientists). Just like the perimeter between the south tip of the Baffin Island and the north tip of Newfoundland once failed, ending the Ice Ages, the rapid melt water accumulation same way destroys now Greenland’s perimeter barrier at Melville Bay. Wet solidus damage causing lava floods and inlet fjord leaks can suddenly speed it up even more unpredictably.

Here is Professor Oren Lyon Jr.’s (Native American Tradition-Keeper and Historian of the Six Nations who worked at the University of Buffalo), the Internet summary of the Plantagon Declarations: http://www.youtube.com/watch?v=4OjjPETcz6A

There is no point just to observe and repeat only points that appear in the professional literature. I want other communities’ perspectives and wisdom to be also realised and acknowledged:

+ either: the ancient experiences of the ancient people,

+ or: for the huge risks that people take to uncover often illegal practises by the corporations who are often acting in tacit co-operation with government officials, scientists or industrialists who are hostile to admit publically the role of greenhouse gases that violate their pet paradigm that the economic growth can be based on infinite growth from fossil-fuelled supply of goods and services.

Veli Albert Kallio, FRGS
International Guru Nanak Peace Prize Nominee for 2008;
sea level rise risk for global security & economic stability.

Sunday, August 19, 2012

Tipping Points

The increasing melt may be a harbinger of greater changes such as the release of methane compounds from frozen soils that could exacerbate warming, and a thaw of the Greenland ice sheet, which would contribute to rising sea levels, NASA’s top climate scientist, James Hansen, said in an e-mail interview, reports Bloomberg.

“Our greatest concern is that loss of Arctic sea ice creates a grave threat of passing two other tipping points -- the potential instability of the Greenland ice sheet and methane hydrates,” Hansen said. “These latter two tipping points would have consequences that are practically irreversible on time scales of relevance to humanity.”


Above image shows methane levels over a period of four years, from August 1, 2008, to August 1, 2012.


Above image shows methane levels over one years, from August 1, 2011, to August 1, 2012. This shows a marked increase in methane levels on the last of the four years further above.


Above image shows methane levels from August 1, 2012, to August 15, 2012. The image shows high levels of methane across the northern hemisphere. Note the high levels above Greenland.

Tuesday, July 24, 2012

Greenland is melting at incredible rate

The combination-image below shows how much the ice on Greenland melted between July 8 (left) and July 12 (right).

On July 8, about 40% of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and some 97% of the ice sheet surface had thawed by July 12. 

In the image, the areas classified as “probable melt” (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected surface melting. The satellites are measuring different physical properties at different scales and are passing over Greenland at different times. Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory.
For several days this month, Greenland's surface ice cover melted over a larger area than at any time in more than 30 years of satellite observations. Nearly the entire ice cover of Greenland, from its thin, low-lying coastal edges to its two-mile-thick center, experienced some degree of melting at its surface, according to measurements from three independent satellites analyzed by NASA and university scientists.

On average in the summer, about half of the surface of Greenland's ice sheet naturally melts. At high elevations, most of that melt water quickly refreezes in place. Near the coast, some of the melt water is retained by the ice sheet and the rest is lost to the ocean. But this year the extent of ice melting at or near the surface jumped dramatically. According to satellite data, an estimated 97% of the ice sheet surface thawed at some point in mid-July.

This extreme melt event coincided with an unusually strong ridge of warm air, or a heat dome, over Greenland. The ridge was one of a series that has dominated Greenland's weather since the end of May. "Each successive ridge has been stronger than the previous one," said Mote. This latest heat dome started to move over Greenland on July 8, and then parked itself over the ice sheet about three days later. By July 16, it had begun to dissipate.

As the ice warms, it loses albedo, i.e. less sunlight is reflected back into space. Darker surface absorbs more sunlight, accelerating the melting. The image below shows the Greenland ice sheet albedo from 2000 to 2011.

Credit: NOAA Arctic Report Card 2011.

The image below, from the meltfactor blog and by Jason Box and David Decker, shows the steep fall in reflectivity for altitudes up to 3200 meters in July 2012. 



The image below, from the meltfactor blog, shows how the year 2012 compares with the situation at approximately the same time in previous years, 2011 and 2010, which are recognized as being record melt years. 


The photo below shows how dark the ice sheet surface can become.

Photo shot by Jason Box on August 12, 2005
Loss of albedo occurs as the darker bare ground becomes visible where the ice has melted away. Darkening of snow and ice can start even before melting takes place. Warming changes the shape and size of the ice crystals in the snowpack, as described at this NASA Earth Observatory page. As temperatures rise, snow grains clump together and reflect less light than the many-faceted, smaller crystals. Additional heat rounds the sharp edges of the crystals, and round particles absorb more sunlight than jagged ones. 

Dirty ice surrounds a meltwater stream near the margin of the ice sheet. Compared to fresh snow and clean ice, the dark surface absorbs more sunlight, accelerating melting. © Henrik Egede Lassen/Alpha Film, from the Snow, Water, Ice, and Permafrost in the Arctic report from the U.N. Arctic Monitoring and Assessment Programme. From NOAA Climatewatch.
Another factor contributing to darkening is aerosols, in particular soot (i.e. black carbon) from fires and combustion of fuel, dust and organic compounds that enter the atmosphere and that can travel over long distances and settle on ice and snow in the Arctic. 

The July data since 2000, from the meltfactor blog, suggest a exponential fall in reflectivity that, when projected into the future (red line, added by Sam Carana), looks set to go into freefall next year. 

Is a similar thing happening all over the Arctic? Well, the map below, edited from a recent SSMIS Sea Ice Map, shows that sea ice concentration is highest around the North Pole. 



So, can water be expected to show up at the North Pole? Well have a look at the photo from the North Pole webcam below. 


Photo from the North Pole webcam
It does look like melting is going on at the North Pole. Water is significantly darker than ice, meaning the overall reflectivity will be substantially lowered by this water. 

It's important to realize that surface albedo change is just one out of a number of feedbacks, each of which deserves a closer look. 

As shown on the image below, the IPCC describes four types of feedbacks with a joint Radiative Forcing of about 2 W/sq m, i.e. water vapor, cloud, surface albedo and lapse rate. 




The image below, from James Hansen et al., may at first glance give the impression that all aerosols have a cooling effect. 





When components are split out further, it becomes clear though that some aerosols are reflective and have a cooling effect, whereas black carbon has a warming effect, while changes in snow albedo also contribute to warming. On the interactive graph below, you can click on or hover over each component to view their radiative forcing. When isolated from other factors, it's clear that snow albedo has an increasing warming effect.
How much could Earth warm up due to decline of snow and ice? Professor Peter Wadhams estimates that the drop in albedo in case of total loss of Arctic sea ice would be a 1.3 W/sq m rise in radiative forcing globally, while additional decline of ice and snow on land could push the the combined impact well over 2 W/sq m.

Locally, the impact could be even more dramatic. The image below, from Flanner et al., shows how much the snow and ice is cooling the Arctic. 


Image, edited by Sam Carana, from Mark Flanner et al. (2011).
Conversely, above image shows how much the Arctic could warm up without the snow and ice. Due to albedo change, sunlight that was previously reflected back into space will instead warm up the Arctic. What could have a big impact locally is that, where there's no more sea ice left, all the heat that previously went into melting will raise temperatures instead, as described at Warming in the Arctic.

The big danger is methane. Drew Shindell et al. show in Improved Attribution of Climate Forcing to Emissions that inclusion of aerosol responses will give methane a much higher global warming potential (GWP) than the IPCC gave methane in AR4, adding that methane's GWP would likely be further increased by including ecosystem responses. Indeed, as pictured in the image below, accelerated warming in the Arctic could trigger methane releases which could cause further methane releases, escalating into runaway global warming