ABSTRACT
Human activities have changed the composition of earth's atmosphere to such an extent that it is part of the reason why climate scientists call our present geological period the Anthropocene. The changes observed in the earth's climate since the early 20th century are caused primarily by human activities, especially fossil fuel burning, which increases the heat-trapping greenhouse gas level in the atmosphere and also significantly increasing the surface temperature. Climate change would affect hydrology and water resources, as they are closely related and rely on the environmental processes. In this study a synoptic view is presented to better understand the impact of climate change on hydrological processes at the river basin to watershed scale. The major concerns discussed are effect of climate change on evapotranspiration, weather patterns, water discharge, groundwater and topography through case studies on climate and hydrological modeling. The chapter aims to evaluate and demonstrate the effect of that global climate change on watershed hydrology through case studies on climate and hydrologic modeling in different parts of the world.
