Sea-salt aerosol response to climate change: Last Glacial Maximum, preindustrial, and doubled carbon dioxide climates

Sea-salt aerosols represent a significant fraction of the aerosol optical depth over the oceans, and thus their response to changes in climate represents an important potential feedback on climate. Model results for sea-salt aerosols in the Community Atmospheric Model (CAM3) show good agreement with observations for the current climate. Additionally, the current climate model simulations presented here are not sensitive to the sea surface temperature boundary conditions or model resolution. We show model results for the response of sea-salt aerosols to climate change for the Last Glacial Maximum, preindustrial, current, and doubled carbon dioxide climate model simulations. Our model results suggest that globally averaged sea-salt sources, deposition, and loading are not very sensitive to climate change and change <5% for these disparate climates. Regional differences are much larger, with differences in zonally averaged concentrations as large as 40% seen between the current climate and a doubled carbon dioxide climate. While ice core studies show twofold to fivefold changes in sea-salt fluxes between Last Glacial Maximum and the current climate, our simulations cannot reproduce these changes, even after including a proposed sea ice source of sea salts.