He reminded business and political leaders at the World Economic Forum that the conflict in the Darfur region of Sudan was touched off by drought - and he said shortages of water contribute to poverty and social hardship in Somalia, Chad, Israel, the Palestinian territories, Nigeria, Sri Lanka, Haiti, Colombia and Kazakhstan.
"Too often, where we need water we find guns instead," Ban said. "Population growth will make the problem worse. So will climate change. As the global economy grows, so will its thirst. Many more conflicts lie just over the horizon."
He said a recent report identified 46 countries with 2.7 billion people where climate change and water-related crises create "a high risk of violent conflict" and a further 56 countries, with 1.2 billion people "are at high risk of violent conflict." The report was by International Alert, an independent peace-building organization based in London.
Ban noted that it was a drought that precipitated the violence in Darfur, Sudan. "Fighting broke out between farmers and herders after the rains failed and water became scarce," he said of the conflict, which has so far claimed about 200,000 lives and displaced several million people. "But almost forgotten is the event that touched it off - drought, a shortage of life's vital resource."
Ban told the VIP audience that he spent 2007 "banging my drum on climate change," an issue the Forum also had as one of its main themes last year. He welcomed the focus on water this year saying the session should be named: "Water is running out."
"We need to adapt to this reality, just as we do to climate change," he said. "There is still enough water for all of us - but only so long as we can keep it clean, use it more wisely, and share it fairly."
Ban said he will invite world leaders to "a critical high-level meeting" in September to focus on meeting U.N. development goals - including cutting by half the number of people without access to safe drinking water by 2015 - particularly in Africa.
The links between climate change and supplies of clean water were underscored by Fred Krupp, president of Environmental Defense, who suggested that the repercussions of rising temperatures - water shortages and droughts - should spur increased efforts to limit greenhouse gas emissions. "Unless we put caps on the global warming pollution we're throwing up into atmosphere, we're walking into a hell for water shortages," he said.
Ban urged top business executives to join a U.N. project to help poor people gain access to clean water - and he praised Coca-Cola, Dow Chemical and Nestle for their programs and their efforts to be part of the water solution.
Ban's call for global action on water got strong support from several top business executives.
"Water is today's issue," said Andrew Liveris, chairman and CEO of Dow Chemical Co., the world's second largest chemical company. "It is the oil of this century, not a question."
"The technology is there [to improve supplies]. We need the innovation to get the business model and the delivery systems to the table, and we're very committed to doing that," he said.
Liveris said there is a lot of water on the planet and "all of us" should be trying to meet the challenge of affordable desalination of sea water and accessing ground water above and below bedrock.
E. Neville Isdell, chairman and CEO of The Coca-Cola Co., said "this is an issue which ranks next to climate change. ... However, water has got lost as part of the climate change debate."
"The solutions are there," he said, but "the awareness globally and the commitment globally is not there yet."
Isdell urged the world to "raise the issue of water to the level that we have managed to raise the issue of climate change."
He also issued "a clarion cry for engagement," especially with the agricultural sector which uses 70 percent of water resources, compared with 23 percent by industry and 7 percent by "humanity in general."
Peter Brabeck-Letmathe, chairman and CEO of Nestle SA, the world's biggest food and drink company, said "time is still on our side but time is running out, just like water is running out."
He said the demand for biofuels is misguided because 9,000 liters of water are needed to produce one liter of biodiesel.
"This can only work because water has no price," Brabeck said. "If we are going to use 1,950 cubic kilometers of water for biofuels when at the same time our ... water reservoirs are already depleted now, you can see that this strategy that we have today - and which is backed by all major governments - is not the right strategy."
"If you would allow market forces to define how to define the value of the water, we could make a big step forward," Brabeck said.
Krupp agreed that ethanol was not only using massive amounts of water but was diverting food crops for fuel, leading to higher food prices.
"We need a market price ... for industrial users and massive (water) consumers," he said. "That will get tremendous efficiency and be a key to solving this problem."
There also has to be a cap on the amount of water withdrawn from rivers and a solution to the global warming problem "because climate is going to be a great accelerator of water shortages," Krupp said.