Within geography, physical geography is concerned with the characteristics of the natural environment, the atmosphere, the lithosphere and the biosphere; how they influence human activities and how they are affected by them across the face of the globe. It comprises geomorphology, climatology and biogeography, and proceeds by monitoring, modelling and managing environmental change. Geographical research at first concentrated on the direct impacts of glaciation on the geomorphology of Britain, such as the glacial erosion of northern Britain and its indirect impacts, especially the effects of changing sea levels. Physical geographers in the last 100 years have taken some comfort from the knowledge that their skills are applied in matters of public interest and importance. Now the pace of global environmental change is such that these skills will be essential in the next 100 years, in solving some of the great contemporary environmental problems such as global warming, the global disappearance of forests, desertification and water pollution.