How important is land cover change for simulating future climates?

Different future land cover patterns, as represented by two IPCC SRES scenarios, lead to contrasting future climate simulations. Conversion of forest to agriculture in the Amazon leads to local warming equivalent to atmospheric forcing effects. In other tropical locations land cover effects on local temperatures are minimized because of differences in large-scale circulation responses. Mid-latitude climate impacts include cooling with agricultural expansion. Daily diurnal temperature ranges are strongly affected over much of the terrestrial surface. These results indicate that choices humans make about future land use could have a significant impact on future climate change in addition to the effect of atmospheric greenhouse gases and aerosols.