Coastal ecosystem destruction looms

Scientists have issued a blunt warning about the fate of coastal ecosystems around the world, saying many have been so degraded by humans they will collapse if governments don't change the way they're managed.

In a dire report released Wednesday, a team of international researchers said coastal waterways are growing more sick and less able to recover from a host of human activities that could eventually destroy their productivity.

Pollution, overfishing, intensified agriculture and poorly planned tourist operations have already created marine "dead zones" that have been depleted of oxygen and contaminated by chemicals.

"The management failure is serious - it really is a crisis - but the failure is not so bad that we should throw up our hands and start praying," Peter Sale said before presenting the report at a seminar at UN headquarters in New York.

"We need a revision of attitudes and, if the change in attitude doesn't occur, we've got a very grim future ahead of us."

The report, produced by a branch of the United Nations University in Hamilton, projects that in 40 years about 90 per cent of the world's coastlines will be affected by development.

If that projection holds true, fish stocks, water quality, biodiversity and the natural ability of a coastline to protect against storm damage will be negatively affected.

Sale said his report adds urgency to a growing body of research that has found that bays, sea grasses, mangroves, wetlands, fish stocks and corals have all suffered dramatically in the last five decades.

Development has altered the flow of water, over-nutrified the ocean with fertilizers and pesticides, fouled fragile ecosystems with commercial tourism operations and stripped the ocean of its biodiversity.

The researchers warn that continued degradation could be disastrous for the 40 per cent of the world's population that lives within 50 kilometres of a coastline.

"Fourteen of our 17 largest cities are on the coast, so around the world it is the coastlines that are bearing the brunt of the pressure from the human population," Sale said. "And yet these are incredibly important ecosystems in terms of the goods and services they supply us."

It's not clear how much coastal ecosystems are worth worldwide but in Australia alone, tourism and fisheries revenues from the Great Barrier Reef are valued at US$6.22 billion annually.