Impacts of increasing land-ocean interactions on carbon cycles in the Arctic

Global warming accelerates the retreat of cryosphere, significantly impacting the Arctic land-ocean carbon cycle and potentially contributing to climate change feedback. Terrestrial and marine zones are inextricably linked; however, the impacts of retreating cryosphere on the Arctic carbon cycle remain uncertain due to a limited understanding of land-ocean interactions and their biogeochemical response to climate and environmental change. In this review, we synthesized recent advances in research on the impact of increasing Arctic land-ocean interactions on carbon cycles and nutrient exports, as well as how changes in the Arctic Ocean affect the land. In addition to the exports of organic carbon and other key substances from rivers, groundwater, coastal erosion, and meltwater from glaciers and Greenland ice sheet, there is a risk that large amounts of methane can be released into the atmosphere due to the warming of shallow Arctic shelves. Moreover, a decline in sea ice increases the carbon sink of the Arctic Ocean and promotes the growth of terrestrial vegetation in the northern high latitude region. These findings suggest that the Arctic land–ocean interactions are intensifying with climate warming. Therefore, coupled land and ocean carbon cycles should be incorporated into Earth System Models and policymaker's decisions to address climate change.