Water is fundamental to life. Population growth, urbanization, and soaring industrial and agricultural use have increased demand for this precious natural resource. At the most basic level, people need freshwater supplies for drinking, but such resources are increasingly strained in arid areas in parts of America, Africa and inland regions of Asia and Australia. Groundwater reserves are being depleted. Water scarcity is a major problem, affecting one in three people.

Climate data and information underpin the planning and management of surface water supplies and disaster risk reduction: calculations of the frequency and duration of heavy rainfall, the probable maximum precipitation, low-flow and flood forecasting, assessments of water resources, etc. Such data collected on weekly, seasonal and annual timescales and at national, regional and local levels are now more essential than ever to develop operational water management strategies, including flood and drought preparedness and response.