Projected climate change impacts in sundarbans


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A presentation by Mr. Debal Ray, Department of Environment (Government of West Bengal)

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Projected climate change impacts in sundarbans

  1. 1. Projected Climate Change in Sundarbans and its Impacts<br />Debal Ray<br />Department of Environment<br />Government of West Bengal<br />
  2. 2. scenarios<br />
  3. 3. Special Report on Emission Scenarios<br />A1 Scenario<br />Rapid economic growth.<br />A global population that reaches 9 billion in 2050 and then gradually declines.<br />The quick spread of new and efficient technologies.<br />A convergent world.<br />A2 Scenario<br />A world of independently operating, self-reliant nations.<br />Continuously increasing population.<br />Regionally oriented economic development.<br />Slower and more fragmented technological changes<br />
  4. 4. Special Report on Emission Scenarios<br />B1 Scenario<br />Rapid economic growth as in A1, but with rapid changes towards a service and information economy.<br />Population rising to 9 billion in 2050 and then declining as in A1.<br />Reductions in material intensity and the introduction of clean and resource efficient technologies.<br />An emphasis on global solutions to economic, social and environmental stability.<br />B2 Scenario<br />Continuously increasing population, but at a slower rate than in A2.<br />Emphasis on local rather than global solutions to economic, social and environmental stability.<br />Intermediate levels of economic development.<br />Less rapid and more fragmented technological change than in A1 and B1<br />
  5. 5. Scenarios of GHG and Projected Surface Temperature<br />(Modified from IPCC, 2007)<br />
  6. 6. Climatic and non-climatic fragility of sundarbans<br />
  7. 7. Inherent Fragility<br />An estuarine ecosystem is typically rich in biomass but poor in diversity.<br />Typically gives U shaped curve when biodiversity is plotted against salinity<br />Narrow base of biodiversity makes the ecosystem less resilient to stress.<br />Low redundancy species doing same ecological function.<br />Less resistance to invasive species.<br />Future adaptation option largely depends on ecosystem services.<br />
  8. 8. External Stressors<br />High population Pressure <br />Overexploitation of resources<br />Reduced freshwater supply<br />Tilting of Bengal Basin towards<br /> east<br />Sea level Rise & Progressive<br />salinization<br />Pollution<br />
  9. 9. Reasons for disproportionately Large Impact in Sundarbans<br />The phenomenon of recurvature of tropical cyclones in the Bay of Bengal<br />Shallow continental shelf, especially in eastern parts of Bangladesh<br />High tidal range<br />Triangular shape at the head of the Bay of Bengal<br />Almost sea level geography of coastal land<br />High density of population<br />
  10. 10. Projected temperature & precipitation<br />
  11. 11. Projected change in Rainfall in B1 scenario in 2080-2100 compared to 1980 -1999 (mm)<br />
  12. 12. Projected change in Temperature in B1 scenario in 2080-2100 compared to 1980 -1999 (mm)<br />
  13. 13.
  14. 14.
  15. 15.
  16. 16.
  17. 17. Sea level trend<br />
  18. 18. Sea Levels: past and future<br />
  19. 19. Net Sea Level Trends<br />Sinking of delta<br />Unnikrishnan & Shankar, 2007<br />
  20. 20. Important Tide Gauge Locations<br />
  21. 21. PSMSL record of Diamond Harbour<br />
  22. 22. PSMSL record for Sagar<br />
  23. 23. Projections of Global Sea level Rise<br />
  24. 24. Possibility of submergence of low lying areas<br />
  25. 25. Trend of tropical cyclone<br />
  26. 26. Tropical Cyclone : some facts<br /> Although science is not conclusive, IWTC (2006) noted that:<br />If projected rise in sea level due to global warming occurs, then the vulnerability to tropical cyclone storm surge flooding would increase<br />Some increase in cyclone peak wind speed and rainfall will occur if climate continues to warm<br />Model studies and theory project a 3-5% increase in wind speed per degree Celsius increase of sea surface temperature.<br />
  27. 27.
  28. 28. Composite Track of Cyclones in Bay of Bengal<br />1961-1990<br />2071-2100<br />(Unnikrishnan, 2009)<br />
  29. 29. Frequency Distribution of Cyclones in Bay of Bengal<br />1961-1990<br />2070-2100<br />
  30. 30. Trend of Storm Surge<br />Red line –A2 scenario<br />Blue line – B1 scenario<br />
  31. 31. impacts<br />
  32. 32. Projected per Capita Water Availability<br />
  33. 33. Natural Disaster: Relative Risk*<br />*Decile of global distribution of each variable. The higher the value, the higher the relative risk.<br />
  34. 34. Impact of CC on Agriculture in Sundarbans<br />
  35. 35. Projected Loss of Rice in Bangladesh<br /><br />
  36. 36. Endangered plant species <br />Botanical Survey of India, 2006<br />
  37. 37. Endemic Plant Specis<br />Sonneratiaapetala<br />Heritierafomes<br />Phoenix paludosa<br />
  38. 38. Thank you<br />