Geoffrey Lean: God and mangroves

The Almighty may have His critics over the tsunami, but man is to blame for the extent of its devastation
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God and Gaia are in the dock charged with the appalling slaughter of more than 150,000 people in the Christmas tsunami. Even the Archbishop of Canterbury has suggested that it would be natural for people to question divine beneficence in the wake of the catastrophe while others have been quick to blame the callous forces of nature.

But the Almighty and the Earth Mother, popularised by the pro-nuclear scientist James Lovelock, could be forgiven for entering a plea of mitigation. For the toll of the disaster appears to be magnified by two human failures. One is the well-publicised lack of an early-warning system for tsunamis in the Indian Ocean, which Asian leaders agreed to rectify at a one-day emergency summit in Indonesia on Thursday. The second, however, is even more important and has scarcely been mentioned at all: the wholesale and systematic destruction of the defences that nature provides against catastrophes from the sea.

In the past, the shores of the Indian Ocean have been protected from tsunamis, tidal waves and the angry seas stirred up by cyclones and typhoons by a double barrier of coral reefs and mangrove swamps.

The solid barriers of the reefs broke up and slowed down the waves while the tangled roots and dense vegetation of the mangroves absorbed much of their remaining energy. Yet both have been increasingly destroyed over the past 50 years, leaving coasts, and their people, defenceless.

Only a third of the world's coral reefs remain healthy - one-fifth of them have been destroyed completely - after onslaughts ranging from fishing with dynamite to global warming and from sewage pollution to quarrying for building material. The United Nations Environment Programme reported last week that half of the remaining reefs in the Indian Ocean are at risk.

It is the same story with the mangroves. More than half of them have been cut down in Thailand, India and other parts of South-east Asia to make way for towns, tourist resorts and shrimp farms - mainly to supply Western tables.

Preserving these would not, of course, have done anything to stop the massive earthquake that struck just off the coast of Indonesia or to prevent the development of the tsunami - any more than an early-warning system would have done. These, undoubtedly, were acts of God or nature, according to taste. But there is growing evidence that it would have spared many areas from the worst effects of the disaster, both immediately and in the future.

Reports are trickling in that areas which have kept these defences have suffered much less damage than those where they have been destroyed. One is Surin Island off the Thai coast. The island is not far from Phuket, the site of tragic scenes over the past two weeks, but only a handful of its people are known to have died. The reason, say Thai experts, is that a ring of coral still protects the island. It both broke the force of the tsunami and acted as a kind of early-warning system: people saw the waves breaking against the reefs and scrambled for safety.

Halfway across the ocean the Maldives should have been the most vulnerable of all the nations in the area. Very little of its land rises more than a couple of metres above sea level. Indeed, local reports say that the tsunami passed right over the archipelago, briefly submerging it.

But only about 100 people died on its 1,190 islands. The reports say that the waves, devastating elsewhere, passed as a relatively gentle swell. Most people were able to hold on and most of those swept out to sea were able to get back. They put this down to the healthy coral reefs still surrounding the islands which have been protected by strict regulations to preserve the tourist industry. "The waves hit the islands flat, with little force," says Ismail Firag, the Maldives' ministry of tourism's deputy director of planning and development, who has made a special study of tsunamis.

The islands have not escaped scot-free. Most of the land is polluted with salt and other areas have remained under water because the waves broke over walls erected to save them from the rising seas. But the Maldives were spared the horrific devastation that struck Sri Lanka, their neighbour.

Other reports suggest that the northern Andaman Islands and the British-owned Diego Garcia, home to a US naval base, were at least partly protected by their reefs. This comes as no surprise to Dr Doug Masson, a senior researcher at Southampton University's Oceanography Centre. As the wave hit the reefs, quickly passing from deep to shallow water, it would have been broken up with a huge dissipation of energy, he said. Coral is probably what saved the majority of people in the Maldives. The tsunami travelled forward as a broken wave and was far less deadly.

It is much the same story where mangrove forests remain intact. In the badly hit southern India region of Tamil Nadu, the areas with dense remaining mangroves in Pichavaram and Muthupet suffered much fewer casualties and much less damage than places where they have been destroyed. Similar reports are coming in from the island of Penang in Malaysia. And Burma, where much of the mangroves remain intact, appears to be far less affected than its largely denuded neighbour, Thailand.

Venkatigry Vivekandan, head of the 35,000-strong South Indian Fishermen's Federation, said: "Mangroves took the brunt of the attack. They were ravaged and uprooted but they protected their people and villages."

M S Swaminathan, one of India's leading scientists, who is heading an official committee examining developments on the country's coast, said the same: "The dense mangrove forests stood like a wall to save coastal communities living behind them."

This has happened before. In 1999 10,000 people died in a Orissa, India, when a super cyclone brought a 20ft wave crashing more than 12 miles inland. But the worst of the damage was where mangroves have been destroyed; the area around Bhitarkanika, home to one of the world's biggest forests, was largely spared. And the planting of new mangroves along 70 miles of the Vietnamese coast protected the land behind them from the worst typhoon in a decade in 2000 and the worst floods in 30 years just 18 months ago.

It is, of course, early days and the final assessment of the effectiveness of these natural barriers is far in the future. But if these early indications are borne out it suggests that world leaders should be paying even more attention to them than to a tsunami early-warning system. For though a warning could certainly save lives by giving a chance for tourists to get off the beaches and local people to head inland, it would do nothing to prevent wholesale destruction. If that is to be prevented in future disasters, the development of the coasts of the Indian and other oceans will have to be rethought.

Coral reefs and mangroves will have to be preserved and, where possible, regenerated, but the danger is that the lesson has not been learnt and the developers will move in to exploit the newly devastated land, creating even more vulnerable areas. If so, we will have even less reason to blame the effects of a similar catastrophe on Gaia or God.