Arjen Y. Hoekstra, a professor of water management at the University of Twente in the Netherlands, said that nearly four billion people or two-thirds of the population, worldwide experiences severe water shortage at least in a month annually. The new study estimates have presented water scarcity as a bigger problem than thought earlier.

A paper that appeared on Friday in the journal Science Advances carried Dr. Hoekstra and his colleague Mesfin M. Mekonnen’s designed computer model for the creation of a more accurate picture of water scarcity worldwide.

Severe water shortage can result in crop failure and low crop yields, which may cause food price hikes and famine and widespread starvation.

A region experiences severe water scarcity when water consumption by its farms, industries and households becomes double the water amount present in that area.

In an email, Dr. Hoekstra said that it means that groundwater levels have been dropping, lakes have been drying up, less water is present there in rivers, and water supplies for industry and farmers have become threatened.

Everyone won’t suffer equally as in the developed richer countries severe water shortages may indicate water rations for showering and gardening, whereas in very poor nations it could result into drinking water scarcity.

Dr. Hoeskstra said that 50% of the four billion people, experiencing severe water scarcity conditions at least one month every year belong to either China or India. Out of the rest two billion, most of people live in Pakistan, Nigeria, Mexico, Bangladesh, and the western and southern parts of the United States, including Texas, Florida and California.

Earlier studies had estimated that between 1.7 and 3.1 billion people got affected by severe water shortages. However, as per Dr. Hoekstra, the studies either relied on measurements that were quite general in size or used annual averages that weren’t as exact as monthly data.

Dr. Hoekstra said, “Freshwater scarcity is a major risk to the global economy, affecting four billion people directly. But since the remaining people in the world receive part of their food from the affected areas, it involves us all”.