Reconciling the observed surface temperature and precipitation trends in the satellite era

The global-mean surface temperature has increased approximately by 0.5 degree Celsius since 1979 (the start of the satellite era). If one follows the classical view of atmospheric longwave cooling being balanced by latent heating, the surface warming should give rise to a significant increase in the global-mean precipitation. However, the Global Precipitation Climatology Project (GPCP) data show no such trend. Here, we make use of a set of climate simulations created by forcing an atmospheric-only general circulation model (namely the GFDL AM3) with historical sea surface temperature as well as different combinations of anthropogenic and natural forcings. It is found that the increased atmospheric absorption caused by greenhouse gases and aerosols are crucial for reconciling the two observed trends. The implications for empirically constraining aerosol forcing and transient climate response are also discussed.