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

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Presentation on theme: "IMPACTS OF CLIMATE CHANGE ON OUR COASTLINE By Shakira Khan & Edward Robinson Marine Geology Unit Department of Geography & Geology University of the West."— Presentation transcript:

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 climate over 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 ( )

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 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. Increased Rainfall -The Debris Flow 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 October storms: Ivan -September 2004 Dennis –July 2005 Emily – July 2005 Wilma – October 2005

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

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

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

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

15 Storm Surge

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

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

18 Impacts on mangroves along the coast

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

20 Coastline retreat in response to rising sea level (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). Brune Rule

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

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


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