Carbon fluxes in the Arctic Ocean—potential impact by climate change

Abstract

Because of its ice cover the central Arctic Ocean has not been considered as a sink of atmospheric carbon dioxide. With recent observations of decreasing ice cover there is the potential for an increased air–sea carbon dioxide flux. Though the sensitivity of the carbon fluxes to a climate change can at present only be speculated, we know the responses to some of the forcing, including: melting of the sea ice cover make the air–sea flux operate towards equilibrium; increased temperature of the surface water will decrease the solubility and thus the air-sea flux; and an open ocean might increase primary production through better utilization of the nutrients.The potential change in air-sea CO2 fluxes caused by different forcing as a result of climate change is quantified based on measured data. If the sea ice melts, the top 100 m water column of the Eurasian Basin has, with the present conditions, a potential to take up close to 50 g C m?2. The freshening of the surface water caused by a sea ice melt will increase the CO2 solubility corresponding to an uptake of ? g C m?2, while a temperature increase of 1°C in the same waters will out-gas 8 g C m?2, and a utilization of all phosphate will increase primary production by 75 g C m?2.