Simulated Climate and Carbon Cycle Response to Arctic Ocean Albedo Modification

Abstract Arctic Ocean albedo modification (AOAM) has been proposed as a potential means to mitigate some adverse climate impacts of amplified warming over the Arctic. Here we use an Earth system model to examine the response of physical climate and carbon cycle to a hypothetical AOAM implementation in which open seawater albedo in Arctic is set to the albedo of sea ice. Simulation results show that by the end of this century, relative to SSP5‐8.5, AOAM would reduce Arctic mean warming by 1.6°C and delay the occurrence of 4°C Arctic warming by more than 20 years. Meanwhile, AOAM would prevent about 16% Arctic sea ice from melting. Although AOAM directly targets the Arctic Ocean, it has much larger impacts on the land carbon sink than that of the ocean. By 2100, AOAM would reduce 6% Arctic permafrost from thawing and prevent the release of permafrost carbon by 22 PgC compared to that of SSP5‐8.5. On the other hand, AOAM would only decrease ocean carbon storage by 1 PgC. Regarding ocean acidification, AOAM would significantly postpone the onset of sea surface aragonite undersaturation over some Arctic Ocean areas by more than 10 years. Simulations show that a sudden termination of AOAM would cause rapid changes of climate and carbon cycle with a rate much larger than that under SSPs scenarios. Our study demonstrates the potential of AOAM to mitigate some impacts of Arctic warming, and illustrates modest effects of AOAM on the Arctic carbon cycle.