Yuri Shur

Abrupt increase in permafrost degradation in Arctic Alaska

[1]xa0Even though the arctic zone of continuous permafrost has relatively cold mean annual air temperatures, we found an abrupt, large increase in the extent of permafrost degradation in northern Alaska since 1982, associated with record warm temperatures during 1989–1998. Our field studies revealed that the recent degradation has mainly occurred to massive wedges of ice that previously had been stable for 1000s of years. Analysis of airphotos from 1945, 1982, and 2001 revealed large increases in the area (0.5%, 0.6%, and 4.4% of area, respectively) and density (88, 128, and 1336 pits/km2) of degrading ice wedges in two study areas on the arctic coastal plain. Spectral analysis across a broader landscape found that newly degraded, water-filled pits covered 3.8% of the land area. These results indicate that thermokarst potentially can affect 10–30% of arctic lowland landscapes and severely alter tundra ecosystems even under scenarios of modest climate warming.

Arctic patterned‐ground ecosystems: A synthesis of field studies and models along a North American Arctic Transect

Arctic landscapes have visually striking patterns of small polygons, circles, and hummocks. The linkages between the geophysical and biological components of these systems and their responses to climate changes are not well understood. The Biocomplexity of Patterned Ground Ecosystems project examined patterned-ground features (PGFs) in all five Arctic bioclimate subzones along an 1800-km trans-Arctic temperature gradient in northern Alaska and northwestern Canada. This paper provides an overview of the transect to illustrate the trends in climate, PGFs, vegetation, n-factors, soils, active-layer depth, and frost heave along the climate gradient. We emphasize the thermal effects of the vegetation and snow on the heat and water fluxes within patterned-ground systems. Four new modeling approaches build on the theme that vegetation controls microscale soil temperature differences between the centers and margins of the PGFs, and these in turn drive the movement of water, affect the formation of aggradation ice, promote differential soil heave, and regulate a host of system propel-ties that affect the ability of plants to colonize the centers of these features. We conclude with an examination of the possible effects of a climate wan-ning on patterned-ground ecosystems.

Cryogenesis and soil formation along a bioclimate gradient in Arctic North America

[1]xa0In arctic tundra, cryoturbation resulting from frost heave, cracking, and other cryogenic processes produces patterned ground such as nonsorted circles, stripes, nonsorted polygons, and earth hummocks. We studied cryogenic structures and morphological properties of soils associated with patterned-ground features along a bioclimate gradient in Arctic Alaska and Canada from north (subzone A) to south (subzone E). Most of these soils have strongly developed cryogenic features, including warped and broken horizons, and organic matter moved into the upper permafrost. The expression of cryoturbation generally increases with the gradient southward. Soil color reflects the lithology of the soil, weathering, and accumulation of organic matter. The organic horizons form around the circles, and gleyed matrix with redoximorphic features develop in the lower active layers due to saturation above the permafrost. Cryostructure development depends more on hydrology controlled by microtopography than position along the gradient. The cryostructures form due to freeze-thaw cycles and ice lens formation, which include granular, platy, lenticular, reticulate, suspended (ataxitic), ice lens, and ice wedges. On the surface, the density of nonsorted circles reached their maximum in subzones C and D. However, once the vegetation cover was removed, the nonsorted pattern grounds reached their optimum stage and become closed packed in subzone E. Frost heave decreases in the south as the vegetation changes from tussocks to shrub tundra. Cryogenesis is the controlling factor in patterned ground formation resulting in cryoturbated soil profiles, cryostructures, and carbon sequestration in arctic tundra soils.

Concept Study: Exploration and Production in Environmentally Sensitive Arctic Areas

The Alaska North Slope offers one of the best prospects for increasing U.S. domestic oil and gas production. However, this region faces some of the greatest environmental and logistical challenges to oil and gas production in the world. A number of studies have shown that weather patterns in this region are warming, and the number of days the tundra surface is adequately frozen for tundra travel each year has declined. Operators are not allowed to explore in undeveloped areas until the tundra is sufficiently frozen and adequate snow cover is present. Spring breakup then forces rapid evacuation of the area prior to snowmelt. Using the best available methods, exploration in remote arctic areas can take up to three years to identify a commercial discovery, and then years to build the infrastructure to develop and produce. This makes new exploration costly. It also increases the costs of maintaining field infrastructure, pipeline inspections, and environmental restoration efforts. New technologies are needed, or oil and gas resources may never be developed outside limited exploration stepouts from existing infrastructure. Industry has identified certain low-impact technologies suitable for operations, and has made improvements to reduce the footprint and impact on the environment. Additional improvements aremorexa0» needed for exploration and economic field development and end-of-field restoration. One operator-Anadarko Petroleum Corporation-built a prototype platform for drilling wells in the Arctic that is elevated, modular, and mobile. The system was tested while drilling one of the first hydrate exploration wells in Alaska during 2003-2004. This technology was identified as a potentially enabling technology by the ongoing Joint Industry Program (JIP) Environmentally Friendly Drilling (EFD) program. The EFD is headed by Texas A&M University and the Houston Advanced Research Center (HARC), and is co-funded by the National Energy Technology Laboratory (NETL). The EFD participants believe that the platform concept could have far-reaching applications in the Arctic as a drilling and production platform, as originally intended, and as a possible staging area. The overall objective of this project was to document various potential applications, locations, and conceptual designs for the inland platform serving oil and gas operations on the Alaska North Slope. The University of Alaska Fairbanks assisted the HARC/TerraPlatforms team with the characterization of potential resource areas, geotechnical conditions associated with continuous permafrost terrain, and the potential end-user evaluation process. The team discussed the various potential applications with industry, governmental agencies, and environmental organizations. The benefits and concerns associated with industrys use of the technology were identified. In this discussion process, meetings were held with five operating companies (22 people), including asset team leaders, drilling managers, HSE managers, and production and completion managers. Three other operating companies and two service companies were contacted by phone to discuss the project. A questionnaire was distributed and responses were provided, which will be included in the report. Meetings were also held with State of Alaska Department of Natural Resources officials and U.S. Bureau of Land Management regulators. The companies met with included ConcoPhillips, Chevron, Pioneer Natural Resources, Fairweather E&P, BP America, and the Alaska Oil and Gas Association.«xa0less