Mangroves Stop Tsunami

Back in April 2005 we published the feature “Mangroves Stop Tsunami,” which explained that much of the devastation from the tsunami that struck South East Asia in December 2004 could have been avoided if the mangrove forests hadn’t been ripped out to make room for aquaculture and timber. After the devastating cyclone hit Myanmar earlier this month, there was plenty of talk regarding the possible causes, but not much recognition of the role mangrove forests could have played in preventing much of the destruction.

One exception to this was the Hong Kong edition of the Wall Street Journal, where in a May 9th report entitled “Forest Clearing May Have Worsened Toll,” author Jane Spencer provided some facts regarding just how bad the deforestation has been along that Mayanmar’s Irrawaddy Delta. Apparently “vast swaths of mangroves have been cleared over the decades to make way for rice fields and shrimp ponds and to provide wood for fuel.” Spencer went on to report “researchers in Myanmar estimate that 83% of the mangroves in the Irrawaddy were destroyewd between 1924 and 1999.”

This is true elsewhere in the tropics. Thailand, Indonesia and India have developed a shrimp aquaculture industry that engages in completely unsustainable methods – flooding the shrimp ponds with chemicals and antibiotics that in sum will degrade the ponds to the point where every seven years or so they need to abandon the area and move on – each time destroying new mangrove reserves to make room. The Food and Agriculture Organization of the U.N. estimates that 1% of the world’s mangrove forests are being destroyed each year.

The significance of the degree to which mangroves can protect against storm surges and tsunami cannot easily be overstated. Stretching for miles into the ocean, these trees anchor themselves in the mud and sand, their branches and roots absorbing the waves. Further inland along the coastline, larger variants of the species stand as tall trees. These huge forest buffers absorb waves and winds, protecting the inhabited land further inland. Destruction of mangroves, along with land subsidence due to overutilization of ground aquifers, along with increased settlement along tropical coastlines is the reason for rampant destruction – not alleged global warming.

As for global warming, in an article on May 8th in the reputable Investors Business Daily entitled “Al Gore and Climate Ka-Ching,” the author references recent data on modern temperature buoys:

“The trend in the world’s oceans — as shown by measurements taken by a fleet of 3,000 high-tech ocean buoys first deployed in 2003 — is toward cooling. As Dr. Josh Willis, of NASA’s Jet Propulsion Laboratory, noted in a separate interview with National Public Radio, “there has been a very slight cooling” over the buoys’ five years of observation.”

Al Gore has made a great contribution to building global consciousness regarding environmental challenges. But his approach, with the inordinate focus on reducing CO2 emissions from fossil fuel, is not only failing to keep up with recent observational data (for those who are still paying attention), but misdirects priorities away from where they could really help – such as reforesting the world’s coastal mangrove forests – and creates a potentially dangerous moral outrage in the minds of well-meaning but misinformed multitudes everywhere.

Most of the world’s tropical coastlines have a barrier of
Mangrove forests, but only about 70% of these forests remain.

One Response to “Mangroves Stop Tsunami”
  1. Please STOP using the word “STOP”. Mangroves do not “STOP” tsunami. As I mentioned and presented in international/regional forum/conferences (i.e. FAO, ISME & UNEP) and based on the ground information on the effectiveness of mangroves against coastal erosion, cyclone, storm surges and the Indian Tsunami, mangroves only offer limited protection against these natural hazards. In many places, good mangrove stands can’t even stand against normal tidal waves and coastal erosion. Many case studies after the Tsunami also showed total mangrove destruction (uprooted) in areas near epicenter where the wave was storng. What we concern is the massive water flooding in the affected areas after cyclone and tsunami attack. In fact, some experts suggest that heavy coastal vegetation may hold the water longer and make thing worse!

    To reduce the casualty in the future disaster events like cyclone and tsunami, it is beyond mangroves (coastal vegetation) and warning system. In the case of Nargis, warnings have been given by Indian and Bangladesh authorities. The Junta also admitted they did give the warning to the local people. Of couse, knowing junta records, we doubt it! Mangroves and other coastal vegetation rehabilitation are generally good projects after the disaster. But this kind of project take many years (at least more than 20 years for mangroves) to realise their benefits (provide limited protection against natural hazards). It is for long-term benefits (food, fisheries, wood, etc). For immediate response to the next tragedy, we have to make use of warning system and the most important thing is “EFFECTIVE COMMUNICATION”. The Government need to inform local community effectively! Education and awareness are critical. For example, effective communication and evacuation plan in Bangladest have over the years reduced human casualty due to cyclones.


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