Climate Change Impacts on Small Island Developing States (SIDS) Water Resources Prepared by  Floyd Homer [email_address]
Projected Temperature and Precipitation <ul><li>Simulated annual temperature increases at the end of the 21st century rang...
Projected Sea Level Rise <ul><li>Sea level is projected to rise between the present (1980–1999) and the end of this centur...
Projected Hurricanes <ul><li>There is less certainty about the changes in frequency and intensity of tropical hurricanes o...
El Nino Southern Oscillation (ENSO) <ul><li>El Niño/La Niña-Southern Oscillation , or  ENSO , is a  quasi-periodic   clima...
ENSO <ul><li>ENSO causes extreme weather such as floods, droughts and other weather disturbances in many regions of the wo...
Key future impacts and vulnerabilities <ul><li>Water resources  </li></ul><ul><li>Coastal systems and resources  </li></ul...
Water Resources <ul><li>Vulnerable to changes and variations in climate, especially in rainfall, since many small islands ...
Water Stress Likely in the Caribbean <ul><li>Lower rainfall typically leads to a reduction in the amount of water that can...
ENSO Impacts in Pacific SIDS <ul><li>The wet and dry cycles associated with ENSO episodes can have serious impacts on wate...
Potable Water Demand <ul><li>Given the major investments needed to develop storage and provide treatment and distribution ...
 
Key References <ul><li>IPCC Fourth Assessment Report: Climate Change 2007 </li></ul><ul><li>http://www.ipcc.ch/publication...
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Climate Change Impacts on SIDS

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Presentation made at GWP-C's first Regional Media Workshop on IWRM held in Barbados in December 2010.

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Climate Change Impacts on SIDS

  1. 1. Climate Change Impacts on Small Island Developing States (SIDS) Water Resources Prepared by Floyd Homer [email_address]
  2. 2. Projected Temperature and Precipitation <ul><li>Simulated annual temperature increases at the end of the 21st century range from 1.4°C to 3.2°C with a median of 2.0°C, somewhat below the global average. </li></ul><ul><li>Statistical downscaling of HadCM3 results using the selected emission scenarios gives around a 2°C rise in temperature by the 2080s. </li></ul><ul><li>Most models project decreases in annual precipitation and a few increases, varying from –39 to +11%. </li></ul><ul><li>Observations suggest that warming is ongoing. </li></ul><ul><li>Observed trends in precipitation are unclear. </li></ul>
  3. 3. Projected Sea Level Rise <ul><li>Sea level is projected to rise between the present (1980–1999) and the end of this century (2090–2099) by 0.35 m (0.23 to 0.47 m). </li></ul><ul><li>Due to ocean density and circulation changes, the distribution will not be uniform. </li></ul><ul><li>However, large deviations among models make estimates of distribution across the Caribbean, Indian and Pacific Oceans uncertain. </li></ul><ul><li>Global sea level rise over the 20th century is estimated at 0.17 ± 0.05 m. </li></ul><ul><li>The rise in the Caribbean appeared to be near the global mean. </li></ul>
  4. 4. Projected Hurricanes <ul><li>There is less certainty about the changes in frequency and intensity of tropical hurricanes on a regional basis than for temperature and precipitation changes. </li></ul><ul><li>In general there is no clear picture with respect to regional changes in frequency and movement, but increases in intensity are indicated (SW Pacific). </li></ul><ul><li>ENSO fluctuations have a strong impact on patterns of tropical cyclone occurrence in the southern Pacific, and that therefore uncertainty with respect to future ENSO behaviour, contributes to uncertainty with respect to tropical cyclone (hurricane) behaviour. </li></ul>
  5. 5. El Nino Southern Oscillation (ENSO) <ul><li>El Niño/La Niña-Southern Oscillation , or ENSO , is a quasi-periodic climate pattern that occurs across the tropical Pacific Ocean on average every five years, but over a period which varies from three to seven years. </li></ul><ul><li>It is characterized by variations in the temperature of the surface of the tropical eastern Pacific Ocean - warming or cooling known as El Niño and La Niña respectively - and air surface pressure in the tropical western Pacific - the Southern Oscillation . </li></ul><ul><li>The two variations are coupled: the warm oceanic phase, El Niño, accompanies high air surface pressure in the western Pacific, while the cold phase, La Niña , accompanies low air surface pressure in the western Pacific. Mechanisms that cause the oscillation remain under study. </li></ul>
  6. 6. ENSO <ul><li>ENSO causes extreme weather such as floods, droughts and other weather disturbances in many regions of the world. </li></ul><ul><li>Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected. </li></ul><ul><li>During the last several decades the number of El Niño events increased, and the number of La Niña events decreased. </li></ul><ul><li>The studies of historical data show that the recent El Niño variation is most likely linked to global warming. </li></ul>
  7. 7. Key future impacts and vulnerabilities <ul><li>Water resources </li></ul><ul><li>Coastal systems and resources </li></ul><ul><li>Agriculture, fisheries and food security </li></ul><ul><li>Biodiversity </li></ul><ul><li>Human settlements and well-being </li></ul><ul><li>Economic, financial and socio-cultural impacts </li></ul><ul><li>Infrastructure and transportation </li></ul>
  8. 8. Water Resources <ul><li>Vulnerable to changes and variations in climate, especially in rainfall, since many small islands water supply are dependent on rainfall. </li></ul><ul><li>Model projections suggest that a 10% reduction in average rainfall by 2050 is likely to correspond to a 20% reduction in the size of the freshwater lens in some Pacific islands. </li></ul><ul><li>Increases in sea level may also shift water tables close to or above the surface, resulting in increased evapotranspiration, thus diminishing the resource. </li></ul>
  9. 9. Water Stress Likely in the Caribbean <ul><li>Lower rainfall typically leads to a reduction in the amount of water that can be physically harvested, to a reduction in river flow, and to a slower rate of recharge of the freshwater lens, which can result in prolonged drought impacts. </li></ul><ul><li>Recent modeling of the current and future water resource availability on several small islands in the Caribbean, found that many of these islands would be exposed to severe water stress. </li></ul><ul><li>Since most of the islands are dependent upon surface water catchments for water supply, it is highly likely that demand could not be met during periods of low rainfall. </li></ul>
  10. 10. ENSO Impacts in Pacific SIDS <ul><li>The wet and dry cycles associated with ENSO episodes can have serious impacts on water supply and island economies. </li></ul><ul><li>For instance the strong La Niña of 1998 to 2000 was responsible for acute water shortages in many islands in the Indian and Pacific Oceans which resulted in partial shut-downs in the tourism and industrial sectors. </li></ul><ul><li>In Fiji and Mauritius, borehole yields decreased by 40% during the dry periods, and export crops including sugar cane were also severely affected. </li></ul>
  11. 11. Potable Water Demand <ul><li>Given the major investments needed to develop storage and provide treatment and distribution of water, climate change impacts would further decrease the ability of many islands to meet their future requirements. </li></ul><ul><li>Several small island countries have begun to invest, at great financial cost, in the implementation of various augmentation and adaptation strategies to offset current water shortages. </li></ul><ul><li>The Bahamas, Antigua and Barbuda, Barbados, and Trinidad and Tobago have invested in desalination plants. </li></ul>
  12. 13. Key References <ul><li>IPCC Fourth Assessment Report: Climate Change 2007 </li></ul><ul><li>http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch16s16-4-1.html </li></ul><ul><li>El Niño/La Niña-Southern Oscillation </li></ul><ul><li>http://en.wikipedia.org/wiki/El_Ni%C3%B1o-Southern_Oscillation#ENSO_and_global_warming </li></ul>

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