John Madeley

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Natures Barrier to Tsunamis

Church Times, 11 March 2005

 A MANGROVE doesn’t look like much. A kind of shrubby tree, which has tangled roots above the ground, and grows in muddy, mainly tropical, coastal swamps, it is just there, part of nature. The problem is that the mangrove isn’t there, at least not in the way it used to be.

The UN Food and Agricultural Organisation says that 40 per cent of the world’s mangrove forests are in Asia, but many of these have been destroyed in recent years to make way for shrimp farms and tourism, among other things. Some of these developments have been encouraged by the World Bank and aid agencies.

Asian coastlines that were once lined with thick strands of resilient mangroves now lie exposed. Nature’s buffer zones have been flattened. When the tsunami struck on 26 December, the barriers had gone, and the sea crashed over. Asian scientists are now speaking out about how the loss of mangroves seriously escalated the disaster. While the Asian press has reported this, the British press has remained largely silent.

Mangroves play an essential part. They act as a barrier, protecting coastlines and the hinterland by absorbing the energy of waves. They provide double protection. A layer of red mangroves, with flexible branches and tangled roots, absorbs the first shock waves. A second layer of tall, black mangroves then operates like a wall, withstanding much of the sea’s fury.

“The severity of this disaster could have been greatly lessened, and much loss in human life and suffering could have been averted, had healthy mangrove forests, coral reefs, sea-grass beds, and peatlands been conserved in a healthy state along these same now devastated coastlines,” says Alfredo Quarto, executive director of the Mangrove Action Project.

The destruction has been on a huge scale. Since the 1960s, fish farming in Thailand has resulted “in a loss of over 65,000 hectares of mangroves”, says Devinder Sharma, an agricultural-policy analyst based in New Delhi.

In Indonesia, Java has lost 70 per cent of its mangroves in the past 30 years, Sulawesi 49 per cent, and Sumatra 36 per cent. In India, “mangrove cover has been reduced to less than a third of its original in the past three decades,” says Dr Sharma.

Aid agencies and governments have supported shrimp-farming, without paying attention to social and ecological security. Scientific findings confirm that mangroves, “if in their original state, could have served as a vital protective buffer against the tsunami”, Dr Quarto maintains.

Asian coastlines where mangroves are still largely intact have suffered far less damage in the tsunami. On the Indonesian island of Simeulue, 25 miles from the epicentre of the earthquake, only four deaths were reported from a population of about 76,000. The island has a vast mangrove area. Eyewitnesses reported that no waves penetrated the mangrove belt, but that the water rose smoothly, like a rising tide.

A group of five villages, 60 miles south-east of Banda Aceh, was also reported to have been saved by extensive mangroves. But similarly populated places on the mainland had casualties in the tens of thousands.

In Malaysia, in areas where the mangrove forests were intact, there was again reduced damage, according to the Penang Inshore Fishermen Welfare Association. In India and Sri Lanka, a similar picture has emerged.

MANGROVES saved lives on 26 December, and could have saved many more. They have often served “as a barrier to the fury of water”, says Professor M. S. Swaminathan, who holds the UNESCO Chair in Ecotechnology in Madras.

A mangrove belt 100 metres wide, with a density of two to three trees every three metres, could have considerably reduced the height of the waves and prevented people from being dragged out to sea, says Faizal Parish, director of the Global Environment Centre in Malaysia.

The part played by consumers in Western countries cannot escape attention. More than 70 per cent of shrimp farming is now in Asia. Shrimp consumption in Western Europe, North America and Japan has tripled in the past ten years. “Over the last several decades,” says Jeff McNeely, chief scientist of the Swiss-based World Conservation Union, “Many mangroves have been cleared to grow shrimp ponds, so that we, here in Europe, can have cheap shrimps.”

These shrimps and prawns are bought by Europeans “at a price that does not include the environmental cost”, says Dr McNeely. Nor does it cover the loss of life.

Much devastation could have been avoided, and “can be avoided in the future, if we take some basic steps”, Dr Quarto argues. He wants to see the re-establishment of mangrove buffer-zones, “greenbelts”, along threatened zones.

“Denuded coastlines will, if left unprotected, face future disasters. As sea levels rise, and as hurricane and tsunami threats mount, extensive mangrove restoration and conservation programmes must be undertaken,” he says.

It is now clear that the December disaster was not all nature’s fault.