1 bn will face water shortage by 2050

Rapid urban growth and climate change will leave more than 1 billion urban dwellers with a water shortage by 2050, according to a study published in the Proceedings of the National Academy of Sciences. The study shows urban growth rates alone leaving 993 million city residents living on less than 100 liters of water a day. The effects of climate change add 100 million people to that toll.

The 100-liter-per-day benchmark comes from the World Health Organization and the U.S. Agency for International Development. Both recommend it as the minimum amount for consumption in normal uses like bathing, drinking and cooking. In contrast, the average American uses 376 liters a day!

Between now and 2050, the study projects the world will add 3 billion people in cities, most of them in developing areas in India, West Africa and China. Much of this urban growth will occur in areas with seasonal water shortages. The study projects 3.1 billion people will be dealing with seasonal water shortages by 2050.

Agriculture, the world's biggest water consumer, is also one of its the biggest wasters. The report recommends improving the industry's efficiency and cites previously successful approaches. One, in South Africa, had farmers remove plantations of non-native trees that require a lot of water to survive.