A global climate model (GENESIS) with a land-surface transfer scheme (LSX). Part II: CO₂ sensitivity

The sensitivity of the equilibrium climate to doubled atmospheric CO₂ is investigated using the GENESIS global climate model version 1.02. The atmospheric general circulation model is a heavily modified version of the NAR CCM1 and is coupled to a multicanopy land-surface model (LSX); multilayer models of soil, snow, and sea ice; and a slab ocean mixed layer. Features that are relatively new in CO₂ sensitivity studies include explicit subgrid convective plumes, PBL mixing, a diurnal cycle, a complex land-surface model, sea ice dynamics, and semi-Lagrangian transport of water vapor. The global annual surface-air warming in the model is 2.1°C, with global precipitation increasing by 3.3%. Over most land areas, most of the changes in precipitation are insignificant at the 5% level compared to interannual variability. -from Authors