50% of the world's population lacks fresh water by 2050

Half of the world's 9 billion people may face a shortage of freshwater by 2050, if governments fail to cooperate in protecting water resources.

>>>Clean water and talking numbers

The warning was made by 500 scientists around the world at the Conference on Water Resources, which took place in the city of Bonn in Germany.

According to scientists, fresh water is not an infinite renewable resource because in many cases, groundwater resources that humans exploit cannot recover quickly.

Professor Stuart Bunn, director of the Australian Institute of Rivers and Rivers, said there are many causes for water resources such as climate change, environmental pollution, water resource abuse and mismanagement. Climate change may increase the frequency and severity of droughts, floods, heat waves and storms.

Nitrogenous agricultural fertilizer waste has caused more than 200 'dead zones' in the seas and estuaries. Low-cost technology to pump water from the ground and river leads to overuse or waste of water for irrigation and other industries.

In addition, rapid population growth also pushed demand to exceed supply.

Poor countries will suffer the most due to their low resilience. People who live in areas of conflict, political instability will face more difficulties because of competition for water resources.

Developed countries will also be unable to avoid the risk of water shortage. For example, in Europe, some water sources are gradually depleted by over-exploitation of irrigation without following any sustainable development plans.

At the conference, scientists called on politicians to set new goals to improve water resources according to the goals of sustainable development, replacing the UN Millennium Development Goals, which will expire in 2015.