In less than 20 years, close to two billion people will be without water and two thirds of the world will not have enough water, the United Nations Food and Agriculture Organization (FAO) warned here on Wednesday.

According to the head of FAO's Water, Development and Management Unit, Pasquale Steduto, water use has expanded at twice the rate of population growth over the past 100 years creating conditions of water scarcity.

Water shortages are obviously most acute in the driest areas of the world, which are home to more than 2 billion people and to half of all poor people.

Agriculture is the number-one user of water worldwide, accounting for about 70 percent of all freshwater withdrawn from lakes, waterways and aquifers around the world.

"Water has a major impact on the capacity of people everywhere to improve their lives. In many regions, farmers trying to produce enough food and income face the added challenges of repeated droughts and competition for water," Steduto said.

One way to deal with water scarcity is through farming-related techniques that harvest more rainfall, reduce waste in irrigation and increase productivity, and in changes in crop and dietary choices, Steduto added.

Steduto is currently chairman of the UN's coordinating agency UN-Water, which includes UN departments that have a significant role in tackling global water concerns as well as non-UN partners.

This year Rome-based FAO is coordinating World Water Day, on March 22, which will be dedicated to the theme of "Coping With Water Scarcity" and focus on the need for increased cooperation at international and local levels to protect global water resources.