Science Source

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

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