Climate change impacts on the hydrological cycle

Climate and water on the planet Earth are intimately linked. Water influences the climate, and is influenced by the climate. Every change in the climatic system induces a change in the water system, and the other way round. Climate change has been observed and even a stronger change is projected for the future by climate models. Discussion of changes is presented, with reference to such variables as temperature, precipitation, sea level, river flow, soil moisture, evapotranspiration, groundwater, and cryospheric characteristics. The weight of observational evidence indicates an ongoing intensification of the water cycle, with increasing rates of evaporation and precipitation. Climate change will alter the future world's freshwater resources in several aspects, such as freshwater availability, quality, and destructive potential. The likelihood of deleterious impacts, as well as the cost and difficulty of adaptation, would increase with the extent and the speed of global climate change. One of the effects of climate change is that hydrological extremes become more extreme. This leads to emergence of hot-spots and vulnerable areas, and the need for difficult adaptation. Globally, the negative impacts of climate change on freshwater systems are very likely to outweigh their benefits.