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Permafrost Fragile Nature of Permanently (or not so permanently) Frozen Ground Presented by Julie Brigham-Grette and Beth Caissie Julie Brigham-Grette.

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Permafrost Fragile Nature of Permanently (or not so permanently) Frozen Ground Presented by Julie Brigham-Grette and Beth Caissie Julie Brigham-Grette.

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Presentation on theme: "Permafrost Fragile Nature of Permanently (or not so permanently) Frozen Ground Presented by Julie Brigham-Grette and Beth Caissie Julie Brigham-Grette."— Presentation transcript:

1 Permafrost Fragile Nature of Permanently (or not so permanently) Frozen Ground Presented by Julie Brigham-Grette and Beth Caissie Julie Brigham-Grette and Beth Caissie

2 Continuous Discontinuous

3 Ground cracks Water or sand fall in Process repeats many times for many years

4 Beth Caissie, from Russia B Hallett, Svalbard, NGS Massive ice ices and ground ice Elaborate stone circles

5 Cold is powerful. It freezes subsurface water, which can force frozen ground upward to form cone-shaped mounds with cores of ice pingoson Canadas Tuktoyaktuk Peninsula. Photograph by Bernhard Edmaier

6 High above the treeline in Swiss National Park, icy soil warms in the summer sun, slipping over layers of earth like icing dripping down the side of a cake. Photograph by Bernhard Edmaier

7 Permafrost terrain encompasses vast reaches of the Northern Hemisphere. In Icelands central highlands, braids of summer meltwater flow from a nearby glacier and flank a cluster of ragged ponds. Perched on impermeable ground, the shallow pools spread, likely shaped by prevailing winds. Photograph by Bernhard Edmaier

8 Darker than surrounding Canadian tundra, ponds absorb more heat from the sun, amplify their own melting, and over time thread together into beaded streams. As the Earth warms, its vast frozen lands are being transformed and we are only starting to grasp the consequences. Photograph by Bernhard Edmaier

9 Thawing and refreezing each year, an active layer of soil lies over permafrost. Fine sediments and coarse gravels on the surface shift and tilt as the active layer expands and contracts, sorting themselves over centuries into labyrinths of circles and lines decoration for an Arctic island. Photograph by Bernhard Edmaier

10 Ice wedges penetrate deep into frozen soil, chiseling tundra into room-size polygonsa signature texture of permafrost landscapes. Climate change may be marking the Canadian Arctic, too, as meltwater erodes the edges of some polygons and deepens pools in their centers. Photograph by Bernhard Edmaier

11 Warming waters may have formed the embayment expanding across an icy spit of land in the Canadian Arctic. When carbon-rich blocks of thawing permafrost crumble into the water, they decompose and can release potent greenhouse gases such as methane. Photograph by Bernhard Edmaier

12 In Iceland, where volcanic fire does battle with glacial ice, green folds of hummocky terrain and a reddish slash of oxidized soil rise above a black expanse of newer lava. Photograph by Bernhard Edmaier

13 Drunken Forests

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15 Damage from Melting Permafrost F. Nelson permafrost.html Cherskii, Siberia Fairbanks, AK

16 Permafrost damage in Fairbanks, AK and Tibet Thawing permafrost can render railroad tracks useless, as seen in this photo from the northern Tibetan Plateau taken in the early 1960s. Credit: Tingjun Zhang gallery/perma_frost/0/

17 Engineering Solutions Refrigeration of ground Build on stilts (c)2005 Derek Ramsey

18 Ammonia NH3 refrigeration (temp and pressure driven)

19 IPCC Projections 2100 AD CO 2 ( ) CH 4 ( ) Petit et al. (1999) Nature 399: Carbon Dioxide and Methane: The last 400 thousand years

20 Karen Frey, images. Thawing permafrost forecast to release CO2 and CH4 -- huge areas of Siberia are a gigantic source of additional green house gases, as across many parts of the Arctic

21 Karen Frey; image CH 4

22 Shakova et al, 2010, Science 327 Methane venting from East Siberian Arctic Shelf

23 Katey Walters Videos

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