Where Are Arctic Soils Defrosting? The Thermokarst
Like a giant ice cream cake left outside on a hot summer day, the Arctic is melting. In the land of frozen Earth, new wetlands are appearing, as are lake-sized puddles and kilometers-long rivulets of melt water. Scientists have long known about thermokarst—areas where permafrost has thawed and given way to land surface collapse and eroded gullies. But until now, they did not know just how much of the Arctic landscape was susceptible to thermokarst.
A holey, Swiss cheese-like landscape, thermokarst is distributed widely across the high latitudes of the northern hemisphere. According to new research, it makes up roughly 20 percent of the northern permafrost region. Thermokarst landscapes store as much as half of the region’s soil organic carbon (SOC)—a potentially significant source of future greenhouse gases. A study published in October 2016 in Nature Communications maps this Arctic thaw.
acquired 1990 – 2010
The maps above, which show the northernmost latitudes of North America and Eurasia, were created using data from the study. The map below offers a closer look at Siberia. The different colors reflect the types of landscapes—wetlands, lakes, hillslopes, etc.—where thermokarst is likely to be found today and where it is most likely to form in the future. The darker the color, the higher percentage of the landscape is covered by that landform. Coverage is classified as very high when 60 to 100 percent of the land fits into that category. High means 30 to 60 percent coverage; Moderate is 10 to 30 percent, and low is below 10 percent. Hillslope thermokarst landscapes do not reach very high levels, the researchers found.
In places where the permafrost has melted and become thermokarst, wetlands were the most prevalent landform, accounting for nearly 8 percent of the northern landscape. Lake thermokarst covered 7 percent and hillslope thermokarst was prevalent in 5 percent of the area. However, thermokarst landscapes sometimes overlapped, accounting for the marbled appearance of the maps.
While the three thermokarst landscapes have similar total areas, the paper notes, “their distributions differ with regards to both their spatial concentration and their relations to current climate conditions.” Wetland thermokarst has ‘very high’ coverage in boreal peatland regions like the West Siberian Lowlands and the Mackenzie River Valley. For lake thermokarst, ‘very high’ coverage areas include the Yukon Delta, the Alaska North Slope, and coastal regions along the Kara Sea, Laptev Sea, and East Siberian Sea. The map shows ‘moderate’ and ‘high’ regional coverage of hillslope thermokarst landscapes in tundra regions, including the Seward Peninsula and North Slope of Alaska, the Mackenzie River Valley, and the Canadian Arctic Archipelago.
acquired 1990 – 2010
NASA Earth Observatory maps created by Jesse Allen, using data provided by David Olefeldt, University of Alberta. Caption by Pola Lem.
Olefeldt, D., et al. (2016, October 11) Circumpolar Distribution and Carbon Storage of Thermokarst Landscapes.Nature Communications 8 (1-11). Doi:10.1038/ncomms13043.
NASA Earth Observatory (2011, August 14) Omulyakhskaya and Khromskaya Bays, Northern Siberia.
Source: http://www.ineffableisland.com/2017/01/where-are-arctic-soils-defrosting.html
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Please Help Support BeforeitsNews by trying our Natural Health Products below!
Order by Phone at 888-809-8385 or online at https://mitocopper.com M - F 9am to 5pm EST
Order by Phone at 866-388-7003 or online at https://www.herbanomic.com M - F 9am to 5pm EST
Order by Phone at 866-388-7003 or online at https://www.herbanomics.com M - F 9am to 5pm EST
Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!
HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation.
Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.
MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)
Oxy Powder - Natural Colon Cleanser! Cleans out toxic buildup with oxygen!
Nascent Iodine - Promotes detoxification, mental focus and thyroid health.
Smart Meter Cover - Reduces Smart Meter radiation by 96%! (See Video).