Simulations by the Community Atmosphere Model (CAM) and 15 other climate models suggest that climate sensitivity is linked to continental middle to high latitude present-day springtime albedo. We compare 1xCO2 and 2xCO2 CAM simulations against similar simulations with snow cover fraction purposely increased. Greater snow cover fraction leads to higher albedo and lower temperatures at 1xCO2 but has less influence at 2xCO2 when little snow remains due to global warming. This makes the simulation with higher albedo at 1xCO2 more sensitive to increased CO2, in agreement with past work. We show that the wide variation in simulated snow-albedo feedbacks and climate sensitivities among 15 other models correlates well with variations in the continental middle to high latitude present-day springtime albedo, in agreement with our CAM results. The development of more accurate snow and albedo parameterizations should improve model estimates of climate sensitivity.

Last Updated: 2007-09-06