Climate and land surface models: Role of soil

The role of soil in current climate models is reviewed and discussed, with a focus on developments over the last two decades. Soil modeling may be divided into three major parts: simulation of soil hydrological dynamics, soil biogeochemistry and the soil thermal environment. Each of these three major parts is summarized with a brief description of current best practice and developments. Specific issues and modifications relevant to four extreme environments are highlighted: drylands, tropical moist and wet forests, cold regions, and peatlands and wetlands. Finally, current advances in the areas of hyperresolution and coupled model environments are discussed, which we see as the two leading edges of current soil model development.