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Historical and Projected Trends in Landscape Drivers Affecting Carbon Dynamics in Alaska [electronic resource].

Published:
Washington, D.C. : United States. Dept. of Energy, 2017.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description:
1,383-1,402 : digital, PDF file
Additional Creators:
Los Alamos National Laboratory, United States. Department of Energy, Geological Survey (U.S.), National Aeronautics and Space Administration Announcement, United States. Department of the Interior, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary:
Modern climate change in Alaska has resulted in widespread thawing of permafrost, increased fire activity, and extensive changes in vegetation characteristics that have significant consequences for socio-ecological systems. Despite observations of the heightened sensitivity of these systems to change, there has not been a comprehensive assessment of factors that drive ecosystem changes throughout Alaska. In this paper, we present research that improves our understanding of the main drivers of the spatiotemporal patterns of carbon dynamics using in situ observations, remote sensing data, and an array of modeling techniques. In the last 60 years, Alaska has seen a large increase in mean annual air temperature (1.7 °C), with the greatest warming occurring over winter and spring. Warming trends are projected to continue throughout the 21st century and will likely result in landscape-level changes to ecosystem structure and function. Wetlands, mainly bogs and fens, which are currently estimated to cover 12.5% of the landscape, strongly influence exchange of methane between Alaska's ecosystems and the atmosphere and are expected to be affected by thawing permafrost and shifts in hydrology. Simulations suggest the current proportion of near-surface (within 1 m) and deep (within 5 m) permafrost extent will be reduced by 9–74% and 33–55% by the end of the 21st century, respectively. Since 2000, an average of 678,595 ha/yr was burned, more than twice the annual average during 1950–1999. The largest increase in fire activity is projected for the boreal forest, which could result in a reduction in late-successional spruce forest (8–44%) and an increase in early-succession deciduous forest (25–113%) that would mediate future fire activity and weaken permafrost stability in the region. Climate warming will also affect vegetation communities across arctic regions, where the coverage of deciduous forest could increase (223–620%), shrub tundra may increase (4–21%), and graminoid tundra might decrease (10–24%). Finally, this study sheds light on the sensitivity of Alaska's ecosystems to change that has the potential to significantly affect local and regional carbon balance, but more research is needed to improve estimates of land-surface and subsurface properties, and to better account for ecosystem dynamics affected by a myriad of biophysical factors and interactions.
Report Numbers:
E 1.99:la-ur-17-23048
la-ur-17-23048
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Note:
Published through SciTech Connect.
04/08/2017.
"la-ur-17-23048"
Ecological Applications 27 5 ISSN 1051-0761 AM
Neal J. Pastick; Paul Duffy; Hélène Genet; T. Scott Rupp; Bruce K. Wylie; Kristofer D. Johnson; M. Torre Jorgenson; Norman Bliss; A. David McGuire; Elchin E. Jafarov; Joseph F. Knight.
Funding Information:
AC52-06NA25396
G10AC00588
G08PC91508
View MARC record | catkey: 23775885