When intense winds blow over large surfaces of water, such as the sea, the seawater piles up against the coast causing flooding that threatens lives and crops, as well as infrastructure and property. This happens especially where water is bounded by shallow basins. Storm surges are serious hazards along the east coast of Bangladesh, India and Sri Lanka. The cyclone which hit Bangladesh in November 1970 killed around 300 000 people and the recent cyclone Nargis caused 100 000 deaths in Myanmar, Burma. Whereas in New Orleans, which was recently hit by hurricane Katrina, the loss of lives was significantly
smaller (around1800). Read on to find out why.Cycloneeye_lancidaniele_flickr

The eye of a cyclone (Lanci Daniele/Flickr)

The reason for the much lower loss of life in New Orleans was the accurate weather predictions and warning systems available there. The Science and Development Network presented a series of articles focusing on the nature and impacts of tropical cyclones and on how science and technology can be used for such disaster mitigation, by predicting when and where such events are likely to occur and delivering credible early warnings.  The articles discuss how countries can better forecast tropical cyclones, prepare to adapt to future cyclones and cope with the impacts of extreme events, by highlighting lessons learnt from countries like Bangladesh and India. These articles are intended to inform policy makers, researchers and international donors about ways of improving cyclone management.

The introduction article explains how cyclones develop in South Asia, the damage they cause and what can be done to protect vulnerable population. The second article describes the efforts being made by India to cut deaths in the region through improved storm prediction and research. The third article suggests investing in detailed maps of potential cyclone damage to save lives in Indian Ocean countries. In the fourth article Mark Tadross argues that combining statistical and physical models offers the best hope for predicting changes in local cyclone risks in the Indian Ocean. The fifth article warns that preparing for cyclones can save lives, but to save livelihoods nations must also help people adapt to cyclones’ impacts. The sixth and last article warns that although disaster research can help future interventions, urgency should never excuse the exploitation of survivors.

In a paper entitled ‘Tropical Cyclones in a Warmer Climate’ Professor Lennart Bengtsson, from the University of Reading, describes the climate model of the Max Plunk Institute of Meteorology in Hamburg. His paper discusses likely future changes in tropical cyclones, questioning whether they will become more intense following higher sea surface temperatures. The article outlines the different approaches currently taken to climate modelling and discusses the results of characterising current and future climate using the model, comparing them to observations. What would happen as greenhouse gases emissions causes the climate to become warmer? Most climate models predict stronger tropical cyclones in a warmer climate, as an increase in latent heat provides more energy for the storms. The author claims there is less evidence for a reduction in the frequency of storms in a warmer climate. Still, such a reduction could result from a general weakening of large-scale atmospheric circulation (which reduces the number of cyclones) caused by the rapid increase in water vapour that would follow a rise in global temperatures.

The CABI Environmental Impact database has a large amount of material on effects of a warmer climate on the environment.

Leave a Reply