An overview is offered on the utility of numerical models for simulating and projecting the present and future states of the Earth's climate system. In response to demands for detailed regional information on environmental prediction, considerable efforts have been devoted in recent years to the development and experimentation of models with very high spatial resolution, typically in the range of 10-50 km. Such activities at the Geophysical Fluid Dynamics Laboratory are summarized, with emphasis on the simulation of weather and climate phenomena prevailing in the East Asian sector. Examples of model-generated meteorological features in this region include the continental-scale summer and winter monsoons, rainy episodes associated with Mei-yu (Plum Rain) fronts, diurnal cycle of precipitation, summertime heat waves, typhoons, and wintertime cold air surges. Parallel efforts to develop other building blocks of comprehensive earth system models are also briefly described. These endeavours include the incorporation of dynamical and biogeochemical processes in the oceans, terrestrial hydrology and vegetation, as well as coupling at the interfaces between the atmosphere, hydrosphere and land.