New Delhi, Oct. 26: Humans are devouring the Earth’s natural resources in a manner that threatens humanity’s very survival, a UN report said today, predicting land and water shortages, deaths from pollution and disease, and extinction of species.

Major threats to the planet including climate change, the loss of species, and the challenge of feeding a growing population remain unresolved and have put humanity at risk, the United Nations Environment Programme said in its Global Environment Outlook-4.

“The systematic destruction of the Earth’s natural resources has reached a point... where the bill we hand on to our children may prove impossible to pay,” said Achim Steiner, executive director of UNEP.

The 540-page GEO-4 report said progress to clean up the atmosphere over the past 20 years has been “patchy” and more than two million people die prematurely every year from air pollution — two-thirds of these deaths in Asia.

“We’re at a point at which damage and danger is not far in the future, but it is happening now,” said Rajendra Pachauri, executive director of the energy and resources institute (TERI), one of the collaborating centres in the UNEP exercise.

The report said the world’s resources of freshwater are declining and has predicted that up to 1.8 billion people will live in countries with absolute water scarcity within the next 18 years. The ecosystem is losing its capacity to provide fresh water, food and other services to humans, and marine fish catches are being maintained only by fishing further offshore and deeper in the oceans, it said.

Fossils have revealed five mass extinction of species — all attributed to natural causes. “A sixth major extinction is under way, this time caused ... by human population growth and consumption patterns,” the report said.

“What we need now is action... a will, a resolve to bring about the necessary shift towards sustainability,” Pachauri said, after releasing the report in New Delhi, one of 40 sites worldwide picked for simultaneous launch of the report.

The report indicated that to avert irreversible damage from climate change, emissions of the heat-trapping greenhouse gases need to be cut by 60 to 80 per cent from their 1990 levels by 2050 in the developed countries, and significant cuts for developing countries.

But one climate change expert told The Telegraph that an 80 per cent cut in emissions in the developed countries appears “unrealistic”.