The world’s population is growing by about 80 million people a year, implying increased freshwater demand of about 64 billion cubic metres a year. Competition for water exists at all levels and is forecast to increase with demands for water in almost all countries.
Part of the current pressure on water resources comes from increasing demands for animal feed. Meat production requires 8-10 times more water than cereal production.
Over 1.4 billion people currently live in river basins where the use of water exceeds minimum recharge levels
Over 1.4 billion people currently live in river basins where the use of water exceeds minimum recharge levels, leading to the desiccation of rivers and depletion of groundwater. In 60% of European cities with more than 100 000 people, groundwater is being used at a faster rate than it can be replenished.
15% of the world’s total water withdrawals in 2010 – or about 583 billion m3 - were used for energy production. Water demand for energy will certainly increase as energy demand is expected to increase by more than one third in the period 2010–2035.
Global water withdrawals are projected to increase by some 55% through 2050 due to growing demands from manufacturing (400%), thermal electricity generation (140%) and domestic use (130%).
Thermal power plants are responsible for roughly 80% of global electricity production. Power plant cooling is responsible for 43% of total freshwater withdrawals in Europe, nearly 50% in the USA, and more than 10% in China.
Hydroelectricity is currently the largest renewable source for power generation in the world. Hydropower’s share in total electricity generation is expected to remain around 16% through 2035.
Although hydropower generation is a major water user, most of the water used is returned to the river downstream even though it is in part consumptive (reservoir evaporation) and has important impacts on other attributes of streamflows (timing and quality).