Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Earth Science News .




ICE WORLD
Thawing Permafrost: The speed of coastal erosion in Eastern Siberia has nearly doubled
by Staff Writers
Bremerhaven, Germany (SPX) Oct 31, 2013


Scientists are investigating a coastal area, where waves have hollowed out the thawing cliff line. The melt water which runs down the cliff intensives erosion additionally. Photos: M.N. Grigoriev, Alfred Wegener Institute.

The high cliffs of Eastern Siberia - which mainly consist of permafrost - continue to erode at an ever quickening pace. This is the conclusion which scientists of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research have reached after their evaluation of data and aerial photographs of the coastal regions for the last 40 years.

According to the researchers, the reasons for this increasing erosion are rising summer temperatures in the Russian permafrost regions as well the retreat of the Arctic sea ice.

This coastal protection recedes more and more on an annual basis. As a result, waves undermine the shores. At the same time, the land surface begins to sink. The small island of Muostakh east of the Lena Delta is especially affected by these changes. Experts fear that it might even disappear altogether should the loss of land continue.

The interconnectedness is clear and unambiguous: The warmer the east Siberian permafrost regions become, the quicker the coast erodes. "If the average temperature rises by 1 degree Celsius in the summer, erosion accelerates by 1.2 metres annually," says AWI geographer Frank Gunther, who investigates the causes of the coastal breakdown in Eastern Siberia together with German and Russian colleagues, and who has published his findings in two scientific articles.

In these studies, he and his team evaluated high resolution air and satellite photos from 1951 to 2012 as well as measurements of the past four years. In addition, the researchers surveyed four coastal sections along the Laptev Sea (see map) and on the island of Muostakh.

One example of the changes documented in their research are the warming summers. While the temperatures during the period of investigation exceeded zero degrees Celsius on an average of 110 days per year, the scientists counted a total of 127 days in the years 2010 and 2011. The following year, 2012, the number of days with temperatures above freezing increased to 134.

This increase in temperature is not without consequences. Whereas a thick layer of sea ice used to protect the frozen soil almost all year round, it now recedes in this part of the Arctic for increasing periods of time during the summer months. The number of summer days on which the sea ice in the southern Laptew Sea vanishes completely grows steadily.

"During the past two decades, there were, on average, fewer than 80 ice-free days in this region per year. During the past three years, however, we counted 96 ice-free days on average. Thus, the waves can nibble at the permafrost coasts for approximately two more weeks each year," explains AWI permafrost researcher Paul Overduin.

The waves dig deep recesses into the base of the high coasts. The result: The undermined slopes break off bit by bit. During the past 40 years, the coastal areas surveyed retreated on average 2.2 meters per year. "During the past four years, this value has increased at least 1.6 times, in certain instances up to 2.4 times to reach 5.3 meters per year," says Paul Overduin.

For the little island of Muostakh east of the harbour town of Tiksi, this may well mean extinction.

"In fewer than one hundred years, the island will break up into several sections, and then it will disappear quickly," predicts Frank Gunther. On its northern tip, the island shows fluctuating annual erosion rates between 10 and 20 meters per year, and it has already lost 24 per cent of its area in the past 60 years.

Because the subsurface here consists of more than 80 per cent of ice that has formed within the soil, and since the ice is gradually melting, the island's surface collapses as well. The scientists speak of a 34 per cent loss in volume.

"If one bears in mind that it took tens of thousands of years for the island to form through sedimentary deposition, then its disintegration is proceeding at a very rapid pace," says Paul Overduin.

In addition, long-term studies conducted by AWI scientists show the impact of coastal erosion for the sea as well. Depending on the kind of erosion and the particular structure of the coast, between 88 and 800 tons of plant-, animal, and microorganism-based carbon are currently washed into the sea per year and kilometer of coastline - these are materials that had been sealed in the permafrost thus far.

With regard to the Laptev Sea, this translates into approximately one eighth of the organic carbon that is transported by the Lena River annually - and the Lena is a river that encompasses a drainage basin the size of the Mediterranean.

"We can, however, assume larger quantities if this accelerating coastal erosion we currently observe continues," the scientists write in their subject-specific paper for the Biogeosciences special volume: "Interactions between the land and sea in the Lena Delta Region." Once in the water, carbon may turn into carbon dioxide and, as a result, contribute to the acidification of the oceans: the composition of our oceans becomes less alkaline.

These studies were conducted as part of the PROGRESS project which is funded by the Federal Ministry of Education and Research.

F. Gunther, P. P. Overduin, A. V. Sandakov, G. Grosse and M. N. Grigoriev: Short- and long-term thermo-erosion of ice-rich permafrost coasts in the Laptev Sea region Biogeosciences, 10, 4297-4318 , 2013, doi:10.5194/bg-10-4297-2013 (Link to the special edition "Interactions between the land and sea in the Lena Delta Region")

F. Gunther, P. P. Overduin, A. Baranskaya, T. Opel and M. N. Grigoriev: Observing Muostakh Island disappear: erosion of a ground-ice-rich coast in response to summer warming and sea ice reduction on the East Siberian shelf, The Cryosphere Discuss., 7, 4101-4176 , 2013, doi:10.5194/tcd-7-4101-2013

.


Related Links
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
Beyond the Ice Age






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ICE WORLD
Glacial history affects shape and growth habit of alpine plants
Basel, Switzerland (SPX) Oct 21, 2013
Alpine plants that survived the Ice Ages in different locations still show accrued differences in appearance and features. These findings were made by botanists from the University of Basel using two plant species. So far, it was only known that the glacial climate changes had left a "genetic fingerprint" in the DNA of alpine plants. During the Ice Ages the European Alps were covered by a ... read more


ICE WORLD
Space technologies boost disaster reduction int'l co-op

How to Manage Nature's Runaway Freight Trains

Uruguay to pull peacekeepers from Haiti: president

Storm-battered northern Europe slowly gets back to normal

ICE WORLD
Google boss says US data spying is "outrageous"

Historic Demonstration Proves Laser Communication Possible

UNC neuroscientists discover new 'mini-neural computer' in the brain

Birthing a new breed of materials

ICE WORLD
New study suggests coral reefs may be able to adapt to moderate climate change

Dublin faces water rationing after serious treatment plant problem

UCLA report urges new global policy effort to tackle crisis of plastic litter in oceans

Study maps human impacts on top ocean predators along US west coast

ICE WORLD
Thawing Permafrost: The speed of coastal erosion in Eastern Siberia has nearly doubled

Greenpeace says Russia moving jailed activists to St Petersburg

Vast Antarctic sanctuary plans fail

Melting Arctic sea ice could increase summer rainfall in northwest Europe

ICE WORLD
Study challenges soil testing for potassium and the fertilizer value of potassium chloride

Plant production could decline as climate change affects soil nutrients

Drink it while you can, as wine shortage looms: study

Second GM corn set for EU approval after Court ruling: EU sources

ICE WORLD
Improving earthquake early warning systems for California and Taiwan

Guatemala warns pilots of ash plume from volcano

Tropical Storm Sonia weakens after hitting Mexico

Hundreds evacuated as Indonesia volcano erupts

ICE WORLD
Tanzania halts anti-poaching drive after abuse claims

China backs African bid to suspend ICC Kenya case

Britain military eyes world hotspots training role

Tanzania minister defends anti-poaching campaign as ivory seized

ICE WORLD
Study: Humans made sophisticated stone tools earlier than thought

Did hard-wired fear of snakes drive evolution of human vision?

Hair regeneration method is first to induce new human hair growth

No known hominin is ancestor of Neanderthals and modern humans




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement