In May 2008 a tropical cyclone hit Myanmar (the worst since 1991) causing more than 20,000 deaths (the total is still rising at the time of writing this). The cyclone had deteriorated to category 1 by the time it hit the main populated city of Yangon [http://www.msnbc.msn.com/id/24478247/]. But a 12 foot storm surge at high tide coupled with reduced mangrove protection of shorelines resulted in extreme damage.
Al Gore appeared on that day on NPR to publicly blame it on global warming: [http://www.businessandmedia.org/articles/2008/20080506160205.aspx]. But he has it wrong as usual.
The following figure, from the MSNBC article shows the path of the tropical cyclone.
The following figure shows the Hadley Climate Research Unit temperature anomaly data for the 5x5 degree grid encompassing the area hit by the cyclone. Since the 1930s peak, the temperatures declined into the late 1970s. In 1977-78 the pacific climate shift warmed the area and it has been cooling since. Except for 1998 (due to the strong El Nino that year) recent temperatures have been similar to 100 years ago.
A BBC article provides a more balanced evaluation (“Mangrove Loss ‘left Burma Exposed’ [http://news.bbc.co.uk/1/hi/sci/tech/7385315.stm]) which stated: “ASEAN secretary-general Surin Pitsuwan said coastal developments had resulted in mangroves, which act as a natural defence against storms, being lost. … Encroachment into mangrove forests, which used to serve as a buffer between the rising tide, between big waves and storms and residential areas; all those lands have been destroyed.”
The following figure shows Google satellite imagery for the area of Myanmar hit by the cyclone – the huge deforested areas are clearly visible.
The BBC article goes on to mention the significant effects of mangroves on coastal protection: “A study published in December 2005 said healthy mangrove forests helped save Sri Lankan villagers during the Asian tsunami disaster, which claimed the lives of more than 200,000 people. … While two people died in the settlement with dense mangrove and scrub forest, up to 6,000 people lost their lives in a nearby village without similar vegetation.”
According to the UN FAO, 20 percent of the world’s mangrove forests have been destroyed since 1980 [http://www.fao.org/newsroom/en/news/2008/1000776/index.html]. Myanmar has the third-largest rate of tropical deforestation in the world, behind Brazil and Indonesia, as shown in the following figure from Mongabay.com. The use of wood as fuel is the main reason for deforestation. The UNEP country profile states: “Deforestation in Myanmar, unlike in some other developing countries is not the result of commercial extraction of timber but due to shifting cultivation, fuel-wood problem. … about 81 percent of energy consumption depends upon biomass including woodfuel and agricultural residues, of which consumption of woodfuel account for 84.1 percent. Few rural homes in Myanmar have supply of gas or electricity. Thus there is heavy reliance on fuelwood resulting in depletion of forest cover” [http://countryprofiles.unep.org/profiles/MM/profile/state-of-the-environment/referencemanual-all-pages]
Sea surface temperatures (SST) vary significantly over relatively short periods of time. The following figure shows the SST anomalies for the week of April 30 when the storm started developing [http://www.ncdc.noaa.gov/img/climate/research/sst/wksst.20080430.gif]. The next figure shows a close up of the Bay of Bengal area.
The following figure shows the running 12-month sum of global tropical cyclone energy from 1978 to 2008. Recent years have seen decreasing ACE with current levels similar to the late 970s. [http://www.coaps.fsu.edu/~maue/tropical/]
Historically, fourteen of the world's twenty deadliest cyclones have been Bay of Bengal storms. For more details on tropical cyclone Nargis, see: