On the Sensitivity of Runoff to Climate Change

Human activities associated with the utilization of natural resources benefit societies, but may also cause serious disturbances in the natural environment. In particular, changes in climatic processes may affect both the water resources availability and demand for water by agriculture, industry and population. There is need for an intensive research on possible consequences of climatic variations on hydrological processes, as well as on development of methods for incorporating hydrological uncertainties into planning and operation of water resource systems. The IIASA Water Resources Project concentrates its activity on the effects of anthropogenic changes on inland waters on a global and regional scale. This paper deals with the sensitivity of river runoff to changes in precipitation, air temperature and net radiation. The problem is controversial, mostly due to difficulties in relating the outputs of General Circulation Models to the main hydrological fluxes. At the same time a quantitative assessment of runoff changes due to variations in climate forcing is a prerequisite for rational decision making in water management. The author's discussion of this important issue may contribute to the better understanding of complex interdependence of climatic and hydrological phenomena