Costs of safeguarding the world’s fast-disappearing coral reefs and mangroves are small compared to the benefits they provide from tourism to fisheries, the U.N. Environment Program said on Tuesday.
The report, part of a recent trend trying to place a value on the natural world, said that pollution, global warming and expanding human settlements along coasts were among mounting threats to reefs and mangroves.
“Day in and day out and across the oceans and seas of the world nature is working to generate incomes and livelihoods for millions if not billions of people,” UNEP executive director Klaus Toepfer said in a statement.
The report, to be issued at a conference in Paris, estimated that intact coral reefs were worth $100,000-$600,000 per square kilometer a year to humankind. Mangroves were valued at $200,000-$900,000 a year.
“Most benefits from coral reefs and mangroves arise from fisheries, timber and fuelwood, tourism and shore protection,” it said.
Corals and mangroves protect coastlines from erosion caused by storms, for instance. The report said it was unclear, however, if they had shielded Indian Ocean coasts overall from the disastrous tsunami on Dec. 26, 2004.
By contrast, the cost of protecting a square kilometer of coral reef or mangroves in a marine park was just $775 a year, it reckoned.
It said that all estimates were based on vague data and had to be treated with caution but indicated that better protection made sense in a little-tested branch of ecosystem economics.
It said that about 30 percent of reefs were severely damaged and that 60 percent could be lost by 2030. About 35 percent of mangroves had already disappeared due to logging, disease and conversion to fish farms.
Toepfer said the report should make people “think twice about the pollution, climate change, insensitive development and other damaging practices that are undermining the economic basis for so many coastal communities worldwide.”
In trying to assess the value of reefs, for instance, the survey said that costs of building a concrete breakwater in the Maldives to replace a damaged reef had been $10 million per kilometer.
Under another survey, coral reefs in the Caribbean were estimated to be worth from $2,000 a year in remote areas to $1 million beside a tourist resort where it drew scuba divers.
In Egypt, about 11 percent of gross domestic product came from tourism, with a quarter or tourist revenues from beaches and reefs in the south Sinai.
And mangroves, for instance, were a source of prized building materials because the wood was resistant to rot.
The report, produced by UNEP with the International Coral Reef Action Network and the World Conservation Union, also estimated that reef fisheries were worth between $15,000 and $150,000 per square kilometer a year.
Fish caught for aquariums were worth $500 a kilo against $6 for fish caught as food.