• U.N. report: Polluted water kills about 2.2 million a year; wars claim fewer victims per year
• Report also says wastewater could become valued resource if treated
• Upfront costs to build treatment plants would be expensive, report says

(CNN) -- Contaminated and polluted water now kills more people than all forms of violence including wars, according to a United Nations report released Monday that calls for turning unsanitary wastewater into an environmentally safe economic resource.

ABIDJAN, March 22 (Reuters) - Human beings are flushing millions of tonnes of solid waste into rivers and oceans every day, poisoning marine life and spreading diseases that kill millions of children annually, the U.N. said on Monday. "The sheer scale of dirty water means more people now die from contaminated and polluted water than from all forms of violence including wars," the United Nations Environment Programme (UNEP) said.

Nearly a quarter of a billion people escaped life in the slums over the past decade, the United Nations says. The improvement was thanks largely to housing efforts in China and India, which made "giant strides", according to a report by the UN Habitat agency. But the housing efforts were more than countered by world population growth and the rural exodus to cities. So overall, the total number of slum dwellers actually increased from 776.7m to 827.6m, during the years 2000-2010.

Concerns about global warming, rising fossil fuel prices, and oil insecurity have prompted calls for a new energy economy, one that replaces fossil fuels with renewables. The sun is an enormous reservoir of energy; in fact, the sunlight reaching Earth in just one hour is enough to power the global economy for a whole year.