May 8, 2017

Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra

by
R. Commane, J. Lindaas, J. Benmergui, K.A. Luus, R. Y.-W. Chang, B.C. Daube, E.S. Euskirchen, J.M. Henderson, A. Karion, J.B. Miller, S.M. Miller, N.C. Parazoo, J.T. Randerson, C. Sweeney, P. Tans, K. Thoning, S. Veraverbeke, C.E. Miller, and S.C. Wofsy
,
Proceedings of the National Academy of Sciences
  • States that high-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system
  • Combines aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012–2014
  • Finds that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration October through December
  • States that long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures
  • Results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming
  • Results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season