Humanity's current voracious consumption of resources cannot be sustained, the United Nations Environment Programme (UNEP) cautioned in a new report, warning that the world was already running out of cheap and sources of some essential materials such as oil, copper and gold.

The report, the latest in a series of findings issued by the UN Environment Program (UNEP)'s International Resources Panel, called for global resources consumption to be "decoupled" from economic growth and for resources to be used more efficiently.

According to the report, by 2050, human beings could devour an estimated 140 billion tons of minerals, ores, fossil fuels and biomass per year – three times the current consumption rate, unless economic growth is "decoupled" from natural resource use.

"It is time to recognize the limits to the natural resources available to support human development and economic growth," said the report.

"Decoupling will require significant changes in government policies, corporate behavior, and consumption patterns by the public. Innovation, even radical innovation, will be required," it said.

Due to a growing population and increasingly high levels of consumption in industrialized countries, total resource use grew from 6 billion tons in 1900 to 49 billion tons in 2000. At present, the report estimated total resource use has grown up to 59 billion tons.

"People believe environmental 'bads' are the price we must pay for economic 'goods.' However, we cannot, and need not, continue to act as if this trade-off is inevitable," said Achim Steiner, UN under-secretary-general and UNEP executive director.

"Decoupling is part of a transition to a low carbon, resource efficient green economy needed in order to stimulate growth, generate kinds of employment and eradicate poverty in a way that keeps humanity's footprint within planetary boundaries," he added.

The report noted that the rising cost of many natural resources creates an economic imperative for both developed and developing countries to use less.

"We must realize that prosperity and well-being do not depend on consuming ever-greater quantities of resources. Decoupling is not about stopping growth. It's about doing more with less," the report added.