Ensemble model simulations of the climatic effects of observed historical landcover change in tropical eastern Asia will be presented and compared to the simulated effects of warm SST anomalies in the eastern Tropical Pacific representing idealized El Nino conditions. Results from the landcover change experiments indicate significant surface temperature and precipitation changes in regions far removed from tropical Asia as might be expected from a large surface heating perturbation in this region. Direct comparison with simulated El Nino conditions show that the observed land surface change results in changes in the tropical divergent circulation which are of similar magnitude to all but the largest El Nino events. The interactions between the circulation changes due to El Nino and those due to landcover change are non-linear and will be presented in the context of recently observed changes in natural modes of variability.