Drinks heavyweights SABMiller, Coca-Cola Co and Nestle have called for greater investment in water sustainability amid a growing gap in global supply and demand.

All three drinks firms are members of the 2030 Water Resources Group, which has been formed to help tackle expected water shortages around the world, and particularly in key emerging markets.

The world faces a 40% gap in supply and demand in water by 2030, according to a new report published by the group yesterday (23 November) and endorsed by the United Nations.

"Water scarcity can no longer be tackled by environmentalists alone," said SABMiller CEO Graham Mackay at the launch of the group's report, named Charting Our Water Future.

"We must move the debate on and engage governments, business and industry leaders to show the commitments needed at an economic level to truly address this problem," said Mackay.

Failure to act, he added, will have "severe consequences" for SABMiller and its customers, as well as local communities.

The report, which focuses on China, India, South Africa and Brazil's Sao Paulo state, offers a "fact-based tool" to help businesses and governments decide how best to invest to preserve water supplies.

These four regions represent 40% of the world's population, 30% of global GDP and 42% of projected water demand by 2030.

2030 water needs could be met in these four regions for an estimated US$19bn per country per year, or 0.06% of their combined GDP forecast for 2030, the report found.

To read the full report, published by McKinsey & Company, click here.