Conservation and rights groups used the opening of the World Water Forum in the French port city of Marseilles to highlight the role scarce water resources now plays in conflict and famine around the world.
The World Wide Fund for Nature (WWF) on Monday warned of an escalation in the global water crisis, saying that more than 50 violent conflicts had erupted around the world over water usage since the turn of the century.
WWF said demand for energy and food threatened to exacerbate the already simmering water crisis and would lead to more disputes.
Leaders and environmental experts were gathered in Marseilles for the week-long forum to discuss access to clean water, water rights and the use of modern water-related technologies. Some 20,000 participants were expected to take part in proceedings.
Opening the event, French Prime Minister Francoise Fillon said more than one million people died each year through consuming contaminated water, which he said was "an unacceptable situation."
A UN study released late Sunday called for a radical rethink on how global water resources were allocated, highlighting climate change and the growing food, energy and sanitary needs as a major concern.
"Freshwater is not being used sustainably," UNESCO Director-General Irina Bokova said in a statement. "Accurate information remains disparate, and management is fragmented ... the future is increasingly uncertain and risks are set to deepen."
The report claims that demand from agriculture, which already accounts for around 70 percent of the freshwater used globally, is expected to rise by at least 19 percent by 2050.
Delegates were due to debate the report, which envisages that the world's population will increase by an estimated 2 billion people to 9 billion in the next four decades.
Shortages in Europe predicted
The document claims that, as demand increases, it is probable that there will be shortages across the globe.
"Climate change will drastically affect food production in South Asia and Southern Africa between now and 2030," the report said. "By 2070, water stress will also be felt in central and southern Europe."
The document was written by experts in hydrology, economics and social issues under the banner of the UN's educational, scientific and cultural body, UNESCO.
A separate study published last week by the Organization for Economic Cooperation and Development (OECD) forecast that water demand would rise by 55 percent by 2050, with 40 percent of people likely to live in areas of potential water stress.
On a positive note, the World Health Organization at the same time said the UN's target to raise the proportion of people with access to safe drinking water by 2015 had already been achieved at the end of 2010.
dfm, rc/sjt (AFP, Reuters)