The relative impact of observed change in land cover and carbon dioxide as simulated by a climate model

The relative impact on temperature of a change in land use compared to a change in carbon dioxide was investigated using the Community Climate Model. We performed two 17 year equilibrium simulations, one using an estimate of natural land use at carbon dioxide levels of 280 ppmv, and a second simulation using an estimate of current land use. An identical pair of experiments, but at 355 ppmv, were also performed. Regionally, land use change causes air temperature changes of 50% to 100% of the size induced by the carbon dioxide perturbation although globally averaged the effect of land use change is negligible. The regional impacts of land cover change provides an avenue for improving modeling efforts to simulate recent global change. Including land cover change in transitory simulations may make detecting human-induced climate change easier by permitting a more accurate simulation of regional patterns of change across the Northern Hemisphere.