The world is waking up to huge economic benefits of investing in nature, from forests to coral reefs, after one of the great oversights of the 20th century, the head of the U.N. Environment Program said on Friday.

Achim Steiner told Reuters that governments had long placed too much faith in technology to fix problems such as global warming, water pollution or erosion, instead of looking to natural solutions.

At the beginning of the 21st century we are being thrown back onto nature because you can't fix all these problems with technology, he said.

The disproportion of investments in technological fixes versus investing in nature's ready-made solutions, tried and tested over millions of years, is one of the great oversights of the 20th century, he said.

A U.N.-backed study this week, for instance, indicated that tropical forests provide services worth an estimated $6,120 per hectare (2.47 acres) a year such as food, building materials, water purification or opportunities for tourism.

A new U.N. climate pact due for agreement in December in Copenhagen is set to encourage measures to safeguard tropical forests that soak up greenhouse gases when they grow.

Steiner said that governments should take an even wider view of the value of forests since storing heat-trapping carbon dioxide was only one aspect of a tree's worth.

COST BENEFITS

He said his advice to governments and investors was: Don't just look at a forest as a watershed, or a carbon sink, or as helping biodiversity, or a tourism attraction. Put them all together and then make a cost-benefit analysis.

The cumulative set of benefits you get from talking about a tree ... has to get economically captured, he said.

Among other natural systems, coral reefs provide services as nurseries for fish, protecting coasts from storms, or as scuba-diving holiday destinations. Or insects provide services, for instance, in pollinating crops.

These services are not new. The problem was that we did not capture their value, Steiner said.

Among examples, he said that Kenya planned to raise its forest cover to 10 percent from 1 percent by planting 7 billion trees to help restore an environment degraded by erosion and dwindling water supplies.

Steiner also said a call by UNEP last year for a Green New Deal of investments in clean economic growth to revive struggling economies had helped but that it was too soon to judge if it marked a permanent greener shift.

This concept struck a chord, he said of the idea, inspired by U.S. President Franklin D. Roosevelt's New Deal that helped end the Depression of the 1930s.

Given that it was born out of a crisis I think it's had significant impact, he said, saying that economies such as China had given a high proportion of spending to green jobs.

He said it was too early to predict if the Green New Deal had become a universal concept that will survive the calming down after the crisis.

A lot will depend on Copenhagen. The greatest stimulus package could be a deal in Copenhagen, he said of the new U.N: climate pact. Steiner was an early guest for a Reuters Global Climate and Alternative Energy Summit on September 8-10.

United nations