A recent study found that investing in the protection of nature can produce huge financial returns, often more lucrative than an investment in gold.

This is the first attempt to evaluate the economic value of "ecosystem services", the freebies of the natural world, such as purifying drinking water or protecting coasts from storms.

While individual environmentalists have suggested this phenomenon in the past, this recent comprehensive survey reviewed over 1,100 different studies, covering various regions and ecosystems for a global view. The result? "And we find that with protected areas, for example, no matter how you slice the figures up you come up with a ratio of benefits to costs that's between 25-to-one and 100-to-one," said study leader Pavan Sukhdev, a Deutsche Bank economist.

Putting that into hard numbers helps to understand why this study is so important...and hopefully enlightening. Sukhdev explains the financial possibilities. "If we were to expand marine protection from less than 1% to 30%, say, what would that cost? Establishing reserves, policing them and so on, would cost about $40-50 billion per year - and the annual benefit would be about $4-5 trillion."

The benefits would come from increasing fish catches and tourism revenue and, in the case of reefs,  protecting shorelines from storms.

Other examples given in the report include:

• A Costa Rican study showing that areas of intact forest increase the yield of coffee farms by 20% because they shelter pollinating insects

• A grassland conservation area in New Zealand that supplies the Otago region with free water that would cost $100 million annually to bring in from elsewhere

• In Vietnam, planting and protecting nearly 12,000 hectares of mangroves cost the government $1.1 million, but saved annual expenditures on dyke maintenance of $7.3 million