Seven climate models (with prescribed observed sea-surface temperatures and sea ice extent) were used to explore the biogeophysical impacts of human-induced land cover change (LCC) at regional- and global-scales. In four of the seven models the imposed perturbation led to statistically significant decreases in northern hemisphere summer latent heat flux and decreases in near-surface temperature over the regions of LCC, but only a few significant changes in precipitation. Our results show no common remote impacts of LCC. There was little consistency in the changes simulated by the seven models due to at least four critical factors: 1) the implementation of LCC despite agreed maps of agricultural land, 2) the representation of the phenology of crops and 3) the parameterisation of albedo, and 4) the representation of evapotranspiration (and corresponding parameter choice) for different land cover types. This study highlights a dilemma for both historical hind-casts and future projections; LCC is regionally significant, but it is not feasible within the time frame of the next IPCC (AR5) assessment to implement this change commonly across multiple models.
AJ Pitman, N de Noblet, FT Cruz, EL Davin, GB Bonan, V Brovkin, M Claussen, C Delire, V Gayler, BJJM van den Hurk, PJ Lawrence, MK van der Molen, C Mueller, CH Reick, 3 co-authors. Land use and climate via the LUCID intercomparison study: implications for experimental design in AR5
published, Geophys. Res. Lett., 2009, 36