Healthy coastlines mitigate disasters.

• Author: Mastny, Lisa

Studies of the environmental impacts of last December's Indian Ocean tsunamis point to the vital role healthy coastal resources play in reducing disaster risks. Places that had relatively intact natural barriers, including coral reefs, mangroves, and sand dunes, were largely spared from the devastation of the waves, which killed more than 200,000 people in seven countries.

In February, the UN Environment Programme reported that mangrove forests in Thailand buffered buildings from the force of the massive waves, and vegetated sand dunes in Sri Lanka's Yala and Bundala National Parks prevented seawater from intruding inland. In the Maldives, notes the World Wide Fund for Nature, considerable damage was prevented by the government's diligence in protecting reefs, which bore the brunt of the impact.

Conversely, in areas where natural defenses had been degraded by coastal development, shrimp farming, coral mining, and other human activities, damage and loss of life were much greater. Indian environmentalists have attributed the high death toll and damage in Tamil Nadu state to widespread coastal clearing in recent decades, which destroyed nearly one-third of the mangrove area. In Sri Lanka, some of the heaviest damage was in...