Search Results for Tag: ice
Record permafrost erosion in Alaska bodes ill for Arctic infrastructure
Sitting in my office on the banks of the river Rhine, I am trying to imagine what would happen if the fast-flowing river was eating into the river bank at an average rate of 19 metres per year. It would not belong before our broadcasting headquarters, the UN campus tower and the multi-story Posttower building collapsed, with devastating consequences.
Fortunately, Bonn is not built on permafrost, so we don’t have that particular concern.
Record erosion on riverbank
The record erosion German scientists have been measuring in Alaska probably hasn’t been making the headlines because it is happening in a very sparsely populated area, where no homes or important structures are endangered.
Nevertheless, it certainly provides plenty of food for thought, says permafrost scientist Jens Strauss from the Potsdam-based research unit of the Alfred Wegener Institute for Polar and Marine Research (AWI). He and an international team have measured riverbank, erosion rates which exceed all previous records along the Itkillik River in northern Alaska. In a study published in the journal Geomorphology, the researchers report that the river is eating into the bank at 19 metres per year in a stretch of land where the ground contains a particularly large quantity of ice.
“These results demonstrate that permafrost thawing is not exclusively a slow process, but that its consequences can be felt immediately”, says Strauss.
With colleagues from the USA, Canada and Russia, he investigated the river at a point where it cuts through a plateau, where the sub-surface consists to 80 percent of pure ice and to 20 percent of frozen sediment. In the past, the ground ice, which is between 13,000 and 50,000 years old, stabilized the riverbank zone. The scientists, who have been observing the location for several years, demonstrated that the stabilization mechanisms fail if two factors coincide. That happens when the river carries flowing water over an extended period, and where the riverbank consists of steep cliff, which has a front facing south, and is thus exposed to a lot of direct sunlight.
Minus 12C average no safeguard
The warmer water thaws the permafrost and transports the falling material away, and in spite of a mean annual temperature of minus twelve degrees Celsius, summer sunlight makes it warm enough to send lumps of ice and mud flowing down the slope, according to Michail Kanevskixy from the University of Alaska Fairbanks, lead author of the study.
Overall, between 2007 and 2011, the cliff – which is 700 metres long and 35 metres high – retreated up to 100 metres, resulting in the loss of 31,000 square metres of land area. That is a large area, around 4.3 football fields, the scientists calculate.
In August 2007, they also witnessed how fissures formed within a few days, up to 100 metres long and 13 metres deep.
“Such failures follow a defined pattern”, says Jens Strauss. “First, the river begins to thaw the cliff and scours an overhang at the base. From here, fissures form in the soil following the large ice columns. The block then disconnects from the cliff, piece by piece, and collapses”.
Infrastructure under threat
Although these spectacular events happened far from populated areas and infrastructure, the magnitude of the erosion gives cause for much concern, given the rate at which temperatures are increasing in the Arctic. The scientists want their information to be used in the planning of new settlements, power routes and transport links. They also stress that the erosion impairs water quality on the rivers, which are often used for drinking water.
But what about those areas of the High North where there are settlements and key infrastructure? Russia is starting to get very worried about the effects of increasing permafrost erosion.
Last month the country’s Minister of Natural Resources, Sergey Donsjkoy, expressed grave concern. The Independent Barents Observer quoted the Minister as saying, in an interview with RIA Novosti, he feared the thawing permafrost would undermine the stability of Arctic infrastructure and increase the likelihood of dangerous phenomena like sinkholes. Russia has important oil and gas installations in Arctic regions. Clearly, any damage would have considerable economic implications. There are also whole cities built on permafrost in the Russian north.
High time to adapt
In 2014, I interviewed Hugues Lantuit, a coastal permafrost geomorphologist with the Alfred Wegener Institute for Polar and Marine Research, about an integrated database on permafrost temperature being set up as an EU project. He told me it would be very hard to halt this permafrost thaw, and stressed that permafrost underlies 44 percent of the land part of the northern hemisphere.
“The air temperature is warming in the Arctic, and we need to build and adapt infrastructure to these changing conditions. It’s very hard, because permafrost is frozen ground. It contains ice, and sometimes this ice is not distributed evenly under the surface. It’s very hard to predict where it’s going to be, and thus where the impact will be as the permafrost warms and thaws”.
I remember being shocked to see that people in Greenland were having to use refrigeration to keep the foundations of their buildings on permafrost stable. The scale of the problem is clearly much greater in cities like Yakutsk.
Then, of course comes the feedback problem, when thawing permafrost releases the organic carbon stored within it. Let me give the last word to Hugues Lantuit:
“This is a major issue, because it contains a lot of what we call organic carbon, and that is stored in the upper part of permafrost. And if that warms, the carbon is made available to microorganisms that convert it back to carbon dioxide and methane. And we estimate right now that there is twice as much organic carbon in permafrost as there is in the atmosphere. So you can see the scale of the potential impact of warming in the Arctic.”
DateJanuary 29, 2016 | 3:52 pm
TagsAlaska, Arctic, AWI, Barrow, Climate, Erosion, Greenland, ice, permafrost, research, Russia, science, USA, Warming
Cloudy skies speed up Greenland melt
With Greenland known to be one of the main contributors to global sea level rise, mainly through increased meltwater runoff, it is hardly surprising that there is increasing and widespread scientific interest in finding out exactly what factors influence the melting and to what extent. Approximately half of Greenland’s current annual mass loss is attributed to runoff from surface melt.
In my last Ice Blog post, I looked at a study showing that recent atmospheric warming is reducing the ability of some layers of the Greenland ice sheet to store meltwater. That, in turn, can mean runoff is released into the ocean faster than previously assumed, rushing down a kind of icy chute.
Clouds as a night-time warmer
This week, a study led by the University of Leuven in Belgium was published in Nature Communications that suggests that clouds are playing a greater role in this whole process than previously thought. The study concludes that clouds could be enhancing meltwater runoff by about a third relative to clear skies. The scientists used a combination of satellite observations, ground observations, climate model data and snow model simulations.
The impact is not just because the radiative effect of the clouds directly increases surface melt, but because the clouds actually reduce meltwater refreezing at night. They trap heat like a kind of blanket.
Tristan L’Ecuyer, professor in the Department of Atmospheric and Oceanic Sciences at the University of Wisconsin-Madison and co author of the study, is quoted on the phys. Org science website as saying we could be dealing with another foot of sea level rise around the world over the next 80 years. “Parts of Miami and New York City are less than two feet above sea level; another foot of sea level rise and suddenly you have water in the city”, he warns.
L’Ecuyer stresses that clouds are still not adequately accounted for in climate models. He also stresses that climate models have not kept pace with the rate of melting actually observed on the Greenland ice Sheet.
Viewing clouds from above
Improved satellite coverage is improving the situation. L’Eciyer is affiliated with the UW-Madison Space Science and Engineering Center, a pioneer institute in satellite meteorology. Within the last 10 years, NASA has launched two satellites which, L’Ecuyer says, have changed our view of what clouds look like around the planet. He used “X-ray images” of Greenland’s clouds taken by CloudSat and CALIPSP between 2007 and 2010 to determine the structure of clouds, how high they were in the atmosphere, their vertical thickness and whether they were composed of ice or liquid. The Belgian team combined this data with ground-based observations, snow model simulations and climate model data to map the net effect of clouds. This indicated that cloud cover prevents ice that melts in the daytime sunlight from refreezing at night. That, in turn, flows off as meltwater.
The lead author of the study, Kristof Van Tricht from the University of Leuven, who spent six weeks in Madison last year working with L’Ecuyer, uses the sponge image to describe the snowpack. “At night, clear skies make a large amount of meltwater in the sponge refreeze. When the sky is overcast, by contrast, the temperature remains too high and only some of the water refreezes. As a result, the sponge is saturated more quickly and excess meltwater drains away”.
Clouds can cool the earth’s surface by reflecting sunlight back into space. Or they can trap heat like a blanket. On Greenland, scientists agree that clouds primarily act to trap heat.
As with so many climate phenomena, clouds can both affect the climate, and be changed by it. While on the one hand cloud cover can lead to more warming and more meltwater, the resulting effect on the ice sheet can, in turn, affect the cloud cover itself.
The scientists hope studies like this one, making use of advanced satellite technology, can help make future climate models become more accurate by taking this into account. To date, different models disagree on how clouds affect the largest body of ice and so freshwater in the northern hemisphere.
DateJanuary 15, 2016 | 4:22 pm
Greenland ice a speedy chute to rising seas?
As I checked through the news agencies to keep tabs on what’s been happening with Greenland as 2016 kicks off, the only agency piece I came across is a German story (on AFPD) on how climate change is apparently bringing the world’s biggest island an “economic upswing”. New fish species off the coast, better conditions for agriculture and exportable powdered rock from retreating glaciers are listed amongst the benefits.
No mention of a study published in Nature Climate Change this week showing that recent atmospheric warming – especially the exceptional summers in 2010 and 2012 – are reducing the ability of some layers of the giant ice sheet to store meltwater. That, in turn, can mean runoff is released into the ocean faster than previously assumed, rushing down a kind of icy chute. Clearly, this has considerable implications for global sea level rise.
Approximately half of Greenland’s current annual mass loss is attributed to runoff from surface melt. At higher elevations, the melt does not necessarily equal runoff, because meltwater can refreeze in the porous snow and firn near the surface. Horst Machguth from the Geological Survey of Denmark and Greenland, the lead author of the study, explains the background in a news release by CIRES, the Cooperative Institute for Research on Environment Sciences, Boulder Colorado: “The near-surface of the large ice sheet interior is comprised of snow that is slowly being converted into glacier ice. This porous firn layer can be up to 80 m thick,” he writes. Recent studies indicated that this firn is an important buffer against contributing to sea level rise for decades to come, because it absorbs and stores the meltwater like a sponge, refreezing it to form ice layers as it percolates down from the ice sheet surface. But the authors say the new study shows this may not be the case.
After the Greenland Ice Sheet was hit by a series of warm summers, it was unknown how the firn reacted to exceptional amounts of meltwater, says Machgut. The research aimed to clarify whether the firn was indeed capable of retaining the meltwater, or whether the sponge had been “overwhelmed” by all the extra water.
The scientists drilled cores to sample the firn at sites where similar cores had been drilled 15 to 20 years ago. They found that the amount of refrozen ice layers in the firn had increased substantially over the past two decades in many places, but not everywhere. Cores drilled at lower elevations suggested the recent exceptional meltwater amounts had only trickled through to shallow depths within the firn, conglomerating into massive ice layers directly below the ice sheet surface.
“It appears that the firn was overwhelmed by the melt to a degree where so many ice lenses had formed that they started to hinder percolation of further meltwater. Initially small ice lenses grew to form ice layers of several meters in thickness that act as a lid on top of otherwise sponge-like firn. Radar measurements identified that these massive ice lenses were continuous over tens of kilometres,” says Dirk van As, a co-author of the study from the Geological Survey. “Surface meltwater wants to refreeze in firn locally, which it does at higher elevation, but at lower elevations it hits that lid of ice and is forced to stay at the surface where it cumulates.”
Satellite images show that meltwater then formed rivers on the surface flowing towards the margin of the ice sheet.
More data required
“In contrast to storing meltwater in porous firn, this mechanism increases runoff from the ice sheet,” says CIRES researcher Mike MacFerrin, a second author on the study. “This process has not previously been observed in Greenland. The extent of this ice lid capping the ice sheet firn remains unknown. For this reason, the total amount of additional ice sheet runoff associated with this newly observed process cannot yet be quantified.”
The scientists are now combining their core data with radar measurements from NASA, which cover the entire ice sheet. They say similar changes in firn structure have been observed on various ice caps in the neighbouring Canadian Arctic, which indicates the phenomenon could be widespread in Greenland. Only west Greenland was covered by the new study.
The Greenland ice sheet is already a great concern, with the melting ice rate increasing continually as the atmosphere and the oceans warm. As well as contributing to rising sea levels, the increase in runoff from the ice sheet could also result in feedback processes which could lead to even more melt in the future. The water running down the ice sheet can create darker, slushy channels, the scientists say, which can reduce the albedo effect of the ice sheet, its ability to reflect sunlight away from its surface. As more sunlight is absorbed instead of being reflected off, the surface temperature could warm further.
Given the huge significance of the Greenland ice sheet in terms of global sea level rise and its role in the global climate system, the findings of this study deserve a little more attention than being confined to the publications of the scientific communities.
But maybe potatoes from the “ice island” and mackerel and tuna off its snow-tipped coasts make for more striking headlines?
DateJanuary 6, 2016 | 3:09 pm
TagsArctic, CIRES, Climate, firn, Geological Survey of Denmark and Greenland, glaciers, Greenland, ice, Machguth, meltwater, research, science, Sea level, snow, Warming
As 2015 draws to a close, the NOAA report card on the state of the Arctic and a substantial new study on the Greenland ice sheet belie the myth that the Paris climate conference has put us on track for averting the worst climate change impacts. NOAA confirms that the Arctic experienced record air temperatures and a new low in peak ice extent during 2015, and the scientists warn that climate change is having “profound effects” on the entire marine ecosystem and the indigenous communities that rely on it.
DateDecember 18, 2015 | 11:51 am
TagsArctic, Climate, COP21, Emissions, Greenland, Greenpeace, ice, Living Planet, Paris, Renewables, science, sea ice, UN talks, wildlife
Paris: A COP-out for Arctic Peoples?
As I write, the climate negotiations have been extended into Saturday. Same procedure as every year? While I still hope the seemingly never-ending bickering will result in a document which will at least signal the end of the fossil fuels era, I cannot help feeling a sense of sadness and regret, that this is all way too late for the Arctic, as I discussed in the last blog post. And I wonder how all this feels to indigenous folk living in the High North, as they see their traditional lifestyles melting away.
On a recent edition of DW’s Living Planet programme, Lakeidra Chavis reported on the effect of melting permafrost on indigenous communities in Alaska. Chatting to a colleague in between times about the story, she told me how moved she was to hear how skulls had been washed up in a river as the permafrost at a burial site thawed.
Climate change impacts the present, future – and past
I had a kind of déjà vu feeling. Back in 2008, in those early days of the Ice Blog, I travelled out to Point Barrow, the northernmost point in the USA, with archaeologist Anne Jensen. We visited the site where a village had had to be re-located because of coastal erosion, with melting permafrost and dwinding sea ice. She told me how she was called up by distraught locals in the middle of the night and asked to help recover the remains of their ancestors before they were washed into the ocean. My colleague here in Bonn was surprised to hear that I had conducted that interview back in 2008. How could this have been known at that time already, yet so little publicized?
Victims or culprits?
While a lot of attention is focused (and rightly so) on the impacts on developing countries, Asia, Africa, rising sea levels, this is an issue a lot of people know very little about. In an article for Cryopolitics Mia Bennet puts her finger on an interesting aspect of all this. The Arctic indigenous peoples are living in industrialized, developed states. That gives them an interesting status, somewhere between being victims and perpetrators of climate warming.
“A discourse of victimization pervades much Western reporting on the Arctic”, she writes. A lot of people in the region tend to blame countries outside the region for climate change. She quotes a study in Nature Climate Change in which researchers found that emissions from Asian countries are the largest single contributor to Arctic warming. But she notes that gas flaring emissions in Russia and forest fires and gas flaring emissions in the Nordic countries are the second two biggest contributors. And these industries are often supported by locals, not least because of the jobs and prosperity they bring.
This brings me back to some encounters I had during that trip to Alaska in 2008 – and others since, with Inuit people employed in the oil sector. They were reluctant to accept that the industries that provided their livelihoods could ultimately be literally eroding the basis of their cultures. Russia, the USA, Canada, Norway – are all countries involved in oil and gas exploitation. Some northern regions are highly dependent on the industries which are warming the climate.
“And for their part, Arctic countries must realize that reducing emissions begins at home on the region’s heavily polluting oil platforms and gas flaring stacks – not in Paris”, says Mia Bennet.
All up to Paris?
The sad truth is that even the two-degree target – or the 1.5 currently being debated – will not have much of an impact on Arctic warming.
Mia Bennet puts it bluntly. “Regardless of whether a positive or negative outcome is reached in Paris at COP 21, it will not dramatically affect the Arctic.”
A delegation of indigenous leaders from the Arctic countries is in Paris at the talks. Both the Inuit Circumpolar Council and the Saami Council have sent delegates, with the aim of highlighting the consequences of a warming climate for the polar regions.
Council representatives are from three distinct Inuit regions: Canada, the USA and Greenland. The Chukotka region of Russia also has a substantial Inuit population, who are not directly represented in Paris, but belong to the Council. The Saami Council has representatives from Finland, Russia, Norway and Sweden. Both sets of delegates are attending as observers, without voting rights.
In a position paper, Inuit Circumpolar Council Chair Okalik Eegeesiak of Canada stresses the Inuit’s deep concern about the impacts of climate change on their cultural, social and economic health.
She describes the Arctic’s sensitive ecosystem as a “canary in the coal mine for global change”. Following that metaphor, the canary must be close to suffocating.
The Inuit representatives in Paris are appealing for stronger measures to keep global temperature rise below 1.5 degrees C. They stress that the land and sea sustain their culture and wildlife, “on which we depend for food security, daily nutrition and overall cultural integrity”.
But ultimately, in a world where altruism seldom plays a part, it may be their other argument – the role of the Arctic in influencing the global climate system – that convinces negotiators of the need to work against global warming. With increasing knowledge and awareness of the extent to which the Arctic influences global processes and thus weather and climate all over the globe, the willingness to take measures to prevent further deterioration of the cryosphere is likely to increase. Whether it will be in time is another question. Any negotiator in Paris who has taken a brief moment off to read this – remember, we are not talking about a remote region with a small population. We are all in this together.
DateDecember 11, 2015 | 2:51 pm
TagsAlaska, Arctic, Barrow, Climate, Climate Change College, COP21, Greenland, Greenpeace, ice, Oil, Paris, permafrost, sea ice, snow, UN talks, Warming