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IMPACTS OF CLIMATE CHANGE ON OUR COASTLINE

IMPACTS OF CLIMATE CHANGE ON OUR COASTLINE. By Shakira Khan & Edward Robinson . Marine Geology Unit Department of Geography & Geology University of the West Indies, Mona. What is Climate Change?.

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IMPACTS OF CLIMATE CHANGE ON OUR COASTLINE

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  1. IMPACTS OF CLIMATE CHANGE ON OUR COASTLINE By Shakira Khan & Edward Robinson Marine Geology Unit Department of Geography & Geology University of the West Indies, Mona

  2. What is Climate Change? • Is simply a change of climate, that is, a regional change in temperature and/or weather patterns. • This term is commonly used interchangeably with "global warming" and "the greenhouse effect," but is a more descriptive term and refers to any change in climateover time, whether due to natural variability or as a result of human activity (IPCC, 2007) . • The latter refers primarily to the buildup of man-made gases in the atmosphere that trap the suns heat, causing changes in weather patterns on a global scale. The effects include changes in rainfall patterns, sea level rise, potential droughts, habitat loss and heat stress. The greenhouse gases of most concern are carbon dioxide, methane, and nitrous oxides (www.nsc.org/ehc/glossary.htm )

  3. What does this mean? Scientists have identified some of the likely effects:- • Rainfall - Some regions will experience more extreme rainfall while others will experience drought. • Storms- More frequent and intense storms • Temperature -both atmospheric and sea surface temperate are projected to increase • Sea level - the sea level could rise by more than 40cm by the end of the century.

  4. Increased Rainfall -The Debris Flow Flooding and debris flows occur when normally dry gullies fill to overflowing as infiltration is overwhelmed and all precipitation becomes surface runoff, carrying rock debris. Geological evidence for this kind of hazard: Gullies (blue); Marls and muddy sandstones (brown & orange); Debris fans (darker browns); Significant recent marine erosion event (red bands). The activity in such systems was well described by Eleanor Jones (1981).

  5. Sea level rise is a natural consequence of global warming

  6. The International Panel for Climate Change (IPCC) has examined models of likely sea level rise over the next hundred years:- The models range from a conservative 10 cm to a high of some 80 cm. Most of the rise will be due to thermal expansion of seawater, a lesser amount due to melting of glaciers and ice caps. However, the rate at which the large ice caps (Antarctica and Greenland) will melt is still a matter for debate.

  7. What will this do to a beach?

  8. Cyclic physical processes occurring on beaches • Beach Erosion & Accretion- Carbonate beaches Long Bay, Portland

  9. Progressive Beach recession, Orange Bay, Portland

  10. More intense & frequent storms 13 month period September 2004- October 2005 3 storms: Ivan -September 2004 Dennis –July 2005 Emily – July 2005 Wilma – October 2005 http://www.haitiaction.net/News/storm/IVAN/9_9_4.html

  11. Impacts of climate change on cliffed coastlines Galina, St. Mary Photo: N. Butterfield

  12. Intense storms result in Boulders moving joints When severe wave events occur (hurricanes or tsunami) blocks of rock can be torn off the cliff face and hurled inland

  13. Communities on rocky shores can be engulfed by storm wave debris Some wave debris can be very big… Manchioneal one here

  14. Rising sea levels lead to increased inundation from storm surge…..

  15. Storm Surge

  16. Hazards affecting our coastline J. Tyndale Biscoe Copacabanna STORM SURGE Annotto Bay – Storm surge inundation distances Photo: N. Butterfield

  17. Threat to Wild life – destruction of Habitat Threat to breeding areas, roosting, nesting and fish nurseries Impact of storm surge on Mangroves

  18. Impacts on mangroves along the coast

  19. House destroyed by encroaching sea Impacts on coastal areas- Retreating coastline

  20. Coastline retreat in response to rising sea level Brune Rule (A) Beaches follow a characteristic profile shape based on the wave climate and the types of sediments. (B) When sea level rises, the initial effect is inundation; (C) But eventually enough material will be deposited offshore to re-establish the profile at the higher elevation. Thus, the shore retreat will be based on the slope of the entire beach profile, which is usually flatter than the slope just above the shore. Source: Titus (1986). http://users.rcn.com/jtitus/Holding/fig4.html .

  21. Shoreline retreat Negril Negril Tree 2003 tree line Between 1971 and 2003 sea level rose about 8 cm (IPCC Report , 2007) 2003 base of beach 1971 tree line 1971 base of beach 200 m

  22. Acknowledgements The Marine Geology Unit would like to thank- • The Environmental Foundation of Jamaica • Mr. Rafi Ahmad • Miss Deborah-Ann Rowe • Miss Kadean Mitchell • Mr. Richard Coutou Photos in presentation were taken by MGU, except where noted

  23. THANK YOU! Sediment and freshwater plume from Rio Grande flood, February 13, 1999

  24. Website • Further information about the Marine Geology Unit at the University of the West Indies http://www.mona.uwi.edu/geoggeol/mgu/

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