This study used several model-based tools to analyze the dynamics of the Arctic Basin between
1997 and 2006 as a linked system of land-ocean-atmosphere C exchange. The analysis estimates
that terrestrial areas of the Arctic Basin lost 62.9 Tg C yr-1 and that the Arctic Ocean gained 94.1
Tg C yr-1. Arctic lands and oceans were a net CO2 sink of 108.9 Tg C yr-1, which is within the
range of uncertainty in estimates from atmospheric inversions. Although both lands and oceans
of the Arctic were estimated to be CO2 sinks, the land sink diminished in strength because of
increased fire disturbance compared to previous decades, while the ocean sink increased in
strength because of increased biological pump activity associated with reduced sea ice cover.
Terrestrial areas of the Arctic were a net source of 41.5 Tg CH4 yr-1 that increased by 0.6 Tg CH4
yr-1 during the decade of analysis, a magnitude that is comparable with an atmospheric inversion
of CH4. Because the radiative forcing of the estimated CH4 emissions is much greater than the
CO2 sink, the analysis suggests that the Arctic Basin is a substantial net source of green house
gas forcing to the climate system.