Mangroves role in tsunami questioned


Posted by Rohan Samarajiva on April 4, 2006  /  4 Comments

Mangroves failed to protect coastal villages in ‘04 tsunami – INQ7.net
The World Conservation Union, also known as IUCN, and other nongovernmental organizations earlier reported that mangroves saved lives in Sri Lanka and India — a finding they said could motivate hard-hit communities across Asia to consider replanting mangroves.

A quarter of mangroves have been destroyed in tsunami-impacted countries since the 1980s due to development and the rapid growth of shrimp and fish farms.

But Baird, of James Cook University in Queensland, Australia, and his co-authors argued that governments would be better off putting their resources into an early warning system and evacuation plans. They also called for many coastal communities to be moved to higher ground.

Obviously, this is quite controversial.  I have nothing against mangroves or coastal remediation, which should be done in any case.  The value of the debate this finding is likely to initiate is that it will help us to figure out what really saves lives and focus our limited disaster preparedness resources on those actions.

However, there may be no debate.  Scientific evidence exists that the elephants of Yala showed no change in behavior as a result of the tsunami.  However, no one engaged in debate on this and the theory that animals have an extra sense to perceive oncoming tsunamis is now common wisdom.  People seem to want to believe these kinds of stories because they mesh with some primal narrative of the superiority of “natural” living.

The animal myth is not harmful because it does not misallocate resources.  The mangrove myth (if the research in this article is not refuted, I will call it a myth) could be harmful because real policy actions are riding on  it.

4 Comments


  1. How can anyone know the strength of the NEXT Tsunami? It is good to have this kind of project with the view of protecting nature and not as a protection against a tsunami. The positive way to look at it is to find ways to re-locate families living near beaches to inland and have tsnami warning systems in place. Apart from Thailand, I really doubt any other country has paid enough attention to a tsunami warning system.
    It’s not worth to argue on the above subject and waste the time.

  2. What the Australian scholars are saying is that elevation from sea level contributed more to saving villages than mangroves. If their findings are unchallenged, the limited resources that countries littoral to the Indian Ocean have for disaster mitigation should be spent on moving people to higher locations and for warning systems. In places like the East Coast of Sri Lanka where there is a shortage of land, high or low, this translates into a focus on warning systems.

    It is a cop-out to say everything should be done. The end result of that approach is that nothing is done well.

  3. Dear Samarajiva

    Just a quick clarification. We do not recommend moving people to higher ground, because, this will rarely be practical.

    Logically, the safest course is to build farther from the sea or on higher ground. However, this cannot be considered in isolation from the social economic and emotional cost of shifting entire communities and their livelihoods, the researchers say.

    “Tsunamis are catastrophic but, fortunately, they are rare – and a well-organised early-warning and evacuation plan may be far more effective than buffer zones in saving lives,” Dr Baird said.

  4. Thank for that clarification, Dr Baird. We in Sri Lanka have experienced first hand the difficulties of relocating people, either away from the sea or to higher elevations.

    The specific focus of our activities is community centered disaster preparedness including warning: http://www.lirneasia.net/2006/01/last-mile-hazard-information-project-is-on/

    Therefore, we are in complete agreement on early warning being the most efficacious response. This is, unfortunately, not given due priority by governments in the region: http://www.lirneasia.net/2006/03/clinton-on-the-last-mile-in-disaster-warning/

    We hope that timely and policy relevant research such as yours will help us change the priorities.