CASE STUDY: MANGROVES
Mangroves: a bio-shield against tropical storms
389,000 people (United Nations Institute for
Mangrove forests, which in most places are no
land where mangroves had been cleared, mostly
more than a couple of hundred metres wide, are
since 1989 for paddy fields (Water Resources
found along tropical coasts. They act as a first
Management ES4OD, n.d.), with some later
and vital line of defence against storm and wave
converted for salt production. Cyclone Nargis
damage. In the wake of the Indian Ocean
generated a 3–4-metre-high surge, which easily
tsunami in 2004 and Cyclone Nargis in 2008, it
flooded the largely unprotected paddies and salt
became clear that the damaged caused was
pans. Elsewhere in the world, intact coastal
exacerbated by the over-felling of mangroves,
wetlands reduce the height of hurricane surges
inappropriate coastal development and a lack of
by 4.7–7.9 cm per kilometre (Day and others,
preparedness. Global warming is responsible for
2007). Although wave attenuation varies from
rising sea levels and other more extreme
site to site, 20 km of wetlands have the potential
weather events such as tropical cyclones and
to reduce storm surges by 0.94–1.58 m.
Training and Research [UNITAR], n.d.). Around half of the flooded area comprised reclaimed
floods. It is therefore crucial that decision makers and practitioners develop coastal
With the clearing of the Ayeyarwady Delta’s
management plans that prioritize mangrove
mangroves in the past two decades, this buffer
conservation and development to mitigate these
has been lost. Prior to Cyclone Nargis, the last
climate change impacts.
severe hurricane or cyclone in central Myanmar occurred in 1982. Given predicted sea level rise
When Cyclone Nargis made landfall on
and the increased frequency of extreme weather
Myanmar’s Ayeyarwady Delta in May 2008,
events, post-Nargis reconstruction efforts
84,500 people were killed (United States Agency
should reconsider agricultural expansion into the
for International Development [USAID], 2008).
delta and instead focus on recovering coastal
This huge mortality has been blamed on
wetlands to buffer storm surges, while also
insufficient warnings (Human Rights Watch,
supporting locally-based coastal resource
2010), though other factors are also important.
management and social development to improve
Among these is the large-scale agricultural
communities’ resilience. Such restoration efforts
expansion into the natural habitats of low-lying
could also inform resilience-building in other
areas, which left them exposed to waves. The
heavily populated Asian deltas.
most extensive flooding (271,000 hectares or 57 per cent of the area) occurred in the townships of Labutta and Bogalay, which are home to 55
PROGRESS ON FRESHWATER ECOSYSTEMS - 2021
