Global Warming and Bangladesh
Over the past century, the earth’s surface has increased in temperature by 0.60 C. Scientists believe it is likely for a further rise of earth’s temperatures by another 1.4 to 5.80 C by the end of 21st century. This predicted increase of temperatures is generally known as ‘Global Warming’. Global warming is caused by an increase in the concentration of the greenhouse gases due to human activities. These greenhouse gases are carbon dioxide, methane, nitrous oxide and chlorofluorocarbons. The enhanced greenhouse gases are results of the following human activities :
- Carbon dioxide : deforestation, burning of fossil fuels eg. coal, oil and natural gas for cars, electricity generation, heating of homes etc
- Methane : rice cultivation, livestock (ruminant) raising, coal mining, drilling for oil and natural gas, garbage in landfills
- Nitrous oxide : use of nitrogen based fertilisers, dispose of human and animal waste in sewage treatment plants, automobile exhaust
- Chlorofluorocarbons : use of aerosols, refrigerators, air conditioners
Global warming cause the oceans to warm and expand, inducing a rise in the sea levels (see Figure 1). As a result vast low lying areas (coastal areas) of Bangladesh may be submerged with the rise of sea levels. This sea level rise could further cause an intrusion of saline water into inland causing a destruction of agriculture land, freshwater resources and deterioration in water quality.
Bangladesh may experience an increase in rainfall due to global warming (a warmer air causes more water to evaporate). This could increase the frequency and intensity in rains that may lead to some worse floods. In addition, Global warming would help to melt down icy mountains tops of the Himalayas, from where melted water would flow down through Bangladesh to the sea causing more floods. Furthermore, warmer water and increased humidity may encourage an increase in the frequency and intensity of cyclones (a rise in sea surface temperature helps in formation of increasing cyclones).
Global warming may affect the types of crops being grown in Bangladesh, though it appears that some crops may be benefited in higher temperatures and increased carbon dioxide concentrations (an essential nutrient for photosynthesis) but other crops may be affected. Some plants and animals may not be able to cope with the predicted changed of temperatures that may cause the loss of biodiversity. There is a possibility for an increase of malaria and dengue fever due to more rains and moisture content predicted, which may help to breed mosquitos and other pests
Figure 1 : Graph showing history of sea level and extrapolating possible increases in sea level over the next century. The blue line represents the history of sea level. The yellow line is a high estimate of sea level extrapolated. The red line is a central estimate, and the green line is a low projection (source : www.envirolink.org/orgs/edf/sitemap.html)
The above information was based on various sources including the following: (a) Intergovernmental Panel on Climate Change (IPCC); (b) National Oceanic and Atmospheric Administration, USA; (c) United Nations Environment programme (UNEP); (d) United States Environment Protection Agency (USEPA). The information was compiled by Dr Golam Kibria in June 2005 for http://www.sydneybashi-bangla.com/ . Views expressed in this article are those of the author and are not to be taken to be the views of any others including third parties. The author disclaims any liability for any error, loss or other consequences which may arise from relying on any information in this article. Dr Golam Kibria, Ph.D is a Senior Environmental Scientist with a Rural Water Authority and based in Victoria, Australia.