LAND-USE CHANGE AND CLIMATE

Human activities in Australia and world-wide cause, or contribute to, desertification, deforestation, salinization and soil erosion, and als o to reforestation, irrigation and landscape 'management'. Human-induc ed land-use changes impact on the Earth's climate both locally and on a larger scale, right up to disturbance of the general circulation and hence the global climate. People have become a major environmental ag ent acting on the future climate through land-use change, particularly deforestation (and reforestation), desertification (which often inclu des overgrazing and excessive exploitation of vegetation), agricultura l expansion, and soil erosion and degradation. The largest impact of l and-use change on the future climate seems likely to be as a result of enhanced greenhouse gas emissions. At the same time, rapidly increasi ng populations, especially in the tropics, demand additional food, wat er for drinking and cleaning, and materials for the construction of sh elters-all of which depend upon sustaining a reasonable climate. Clima te and human land-use requirements are linked, but the closeness of th at link varies from intimate dependency to callous disdain. In this pa per, the impacts of human-induced land-use changes on future climate a re explored in the context of the projections of global climate models .