Bangladesh is located between the Himalayas in the north and the encroaching Bay of Bengal to the south. Bangladesh is most vulnerable to natural disasters due to the frequency of extreme climate events and its high population density. The impacts of higher temperatures, precipitation that is more variable, extreme weather events and sea level rise are already felt in Bangladesh and will continue to intensify. The impacts result not only from gradual changes in temperature and sea level but also, in particular, from increased climate variability and extreme events, including more intense floods, droughts, and storms.
Climate change and Biodiversity are interconnected. There is ample evidence that climate change affects biodiversity. According to Millennium Ecosystem Assessment, climate change is likely to become one of the most significant drivers of biodiversity loss by the end of the century. Climate change resulting in sea level rise would cause a severe environmental impact on the living resources including people and biodiversity in the affected areas. There are so many coastline associated islets and islands in the Bay of Bengal in the southern part of Bangladesh, e.g. Shandip of Chittagong, Shahpari and St. Martin of Teknaf, Kutubdia, Moheshkhali and Sonadia of Cox’s Bazar and islets like Nijhumdip, Char Kukrimukri, Char Dale, Char Fashon, etc of Patuakhali, Barguna and Bhola districts.
Human-induced climate change and other heedless human actions are eroding this natural capital at an alarming rate. Globally, species have been disappearing at 50-100 times the natural rate. Based on Current trends, an estimated 3400 plants and 5200 animals species including one in eight of world bird species face extinction (IUCN, 2009). Human-induced climate change tends to reduce the genetic diversity of individual species.
The 2010 Millennium Ecosystem Assessment estimates that by the end of this century, climate change will be the main cause of biodiversity loss. However, as climate changes, the value of biodiversity for food and agriculture will increase. The Intergovernmental Panel on Climate Change (IPCC) reports that a significant number of species will be at risk of extinction as the global mean temperature increases. Of particular concerns are relatives of major crops surviving in the wild.
The Sundarbans is the largest single block of tidal halophytic mangrove forest in the world consisting 6200km² of forest and riverine areas with 334 plant species, 49 species of mammal, 400 fish species, 320 bird species, 53 species of reptile and 11 amphibian species.
The loss of habitats due to salinity intrusion and extreme cyclonic events will significantly hamper the biodiversity composition of Sundarbans. Salinity intrusion will have its impacts on Sundarbans ecosystem and its species. The Goran (Ceriops decandra) and Gewa (Excoecaria agallocha) species rather than Sundri (Heritiera fomes) species due to salinity intrusion will eventually dominate Sundarban forest.
Climate change also threatens fishery, an important source of income and nutrition for the 200 million poor people with more than 98 percent from developing countries. Impacts of climate change will affect fish diversity and availability in particular. Here, what climate change will bring include higher water temperatures, rising sea levels, melting glaciers, changes in ocean salinity and acidity, more cyclones in some areas, less rainfall in others, thus shifting patterns and an abundance of fish stocks. The species of fish that will be able to adapt the changed aquatic conditions will survive but which will not be able to do so will face extinction.
Climate change could have the devastating impact on agriculture. Agriculture is a key economic driver in Bangladesh, accounting for nearly 20 percent of the GDP and 65 percent of the labour force. The performance of this sector has considerable influence on overall growth, the trade balance, and the level and structure of poverty and malnutrition. Moreover, much of the rural population, especially the poor, is reliant on the agriculture as a critical source of livelihoods and employment.
The impacts of climate change could affect agriculture in Bangladesh in many ways:
• The predicted sea-level rise will threaten valuable coastal agricultural land, particularly in low-lying areas.
• Climate unpredictability will make the planning of farm operations more difficult.
The effects of these impacts will threaten food security for the most vulnerable people of Bangladesh. The country’s agriculture sector is already under stress from lack of productivity and population growth. Any further attempt to increase productivity will likely to add pressure to available land and water resources.
Successful adaptation to climate change may depend largely on the ability of species to disperse to new areas but this ability also increasingly impeded by human-induced landscape change. If we cannot mitigate and tackle climate disasters properly, the global biotic community will seriously be in danger in future.