Climate Change Impacts, Adaptation and Vulnerability: Small Islands - South West Pacific Penehuro F. Lefale Lead Author (LA), Chapter 16 Manager, International Cooperation & Development NZ Meteorological Service (MetService) Climate Change 2007: Climate Change Impacts, Adaptation and Vulnerability; Chapter 16: Small Islands
Chapter 16: Small Islands Now available online at http://www.ipccwg2.org/index.html Task: to assess recent scientific information on vulnerability to climate change and sea level rise, adaptation to their effects and implications of climate related policies, including adaptation, to the sustainable development of small islands Small Islands regions: low, mid and high (Indian Ocean, Caribbean, Pacific, Mediterranean)
Small Islands vulnerability Primarily a function of 4 interrelated factors 1. The degree of exposure to climate and climate related factors 2. Their limited capacity to adapt to projected impacts 3. Adaptation to climate change is not a high priority given more pressing problems 4. The uncertainty associated with global climate change projections and their local validity Internal and external processes/stresses: Geographically located in regions most prone to natural hazards (extreme weather events tropical cyclones) Rapid population growth, attempts to increase economic growth thus destroying natural environment, weakening social capital, political instability Most economies reliant on a limited resource base, and are subject to external forces such as globalisation Adaptive capacity generally low, though traditionally there is some resilience in the face of environmental change
February 2005 Natural hazards in Pacific SIDS e.g. tropical cyclones 2005-06 TC season
Highly vulnerable Storm surges associated with Tropical Cyclone Meena, February 1, 2005. Impacts on Traders Jack Bar & Restaurant, Rarotonga, Cook Islands
Box 16.2: Non-climate change threats to coral reefs of small islands A large number of non-climate change stresses and disturbances, mainly driven by human activities can impact coral reefs (Hughes et al., 2003; Nyström, et al., 2000). Indeed, Buddemeier et. al., (2004) believe that the coral reef crisis is almost certainly the result of complex and synergistic interactions among globalscale climatic stresses and local-scale human-imposed stresses. Four human-threat factors: coastal development, marine pollution, overexploitation and destructive fishing, and sediment and nutrients from inland, provide a composite indicator of the potential risk to coral reefs associated with human activity for 800 reef sites (Bryant et.al., 1998). Their map (above) identifies low risk (blue) medium risk (yellow) and high risk (red) sites, the first being common in the insular central Indian and Pacific Oceans, the last in maritime Southeast Asia and the Caribbean archipelago.
Observed Climate Trends Consistent warming trends in all small islands regions over the 1901 to 2004 period trends not linear Annual and seasonal ocean surface and island air temperature have increased by 0.6 to 1.0 o C since 1910 throughout a large part of the South Pacific, southwest of the South Pacific Convergence Zone Decadal increases of 0.3 to 0.5 o C in annual temperatures are only widely seen since the 1970s, preceded by some cooling after the 194o, to the northeast of the SPCZ. Significant increases were detected in the annual number of hot days & warm nights Significantly decreases in the annual number of cool days and cold nights, particularly in years after the onset of El Niño, for the period 1961-2003.
Observed Trends: sea levels Sea level rise varies from place to place. Estimates for whole Pacific Basin: +0.77 to +1.6 mm/yr Max rate of rise in central & eastern Pacific near 90 o E, peaking at over 3 mm/yr Min rate of rise along equator in eastern Pacific, linking through to just west of 180, less than 1.5 mm/yr
Observed Trends: extreme events The global view of tropical storm activity highlights the important role of ENSO in all basins The most active year was 1997 when a very strong El Niño began, suggesting that observed record high Sea Surface Temperatures (SSTs) play a key role In the tropical South Pacific, the distribution of tropical storms and their tracks are dominated by ENSO and decadal variability (IPO), with small islands to the east of the dateline highly likely to receive a higher number of tropical storms during an El Niño event compared to a La Niña event and vice versa.
Future trends Increased seasonal surface air temperature ranging from 0.45 to 3.11 o C by 2100 (baseline 1961-1990). Warming likely to be somewhat smaller than the global average Annual mean warming in all seasons Rainfall: unclear, either marginal increase (e.g. equatorial Pacific) or marginal decrease (e.g. east of French Polynesia in DJF) by 2100. It range from -14.0 to +14.6% for the Southern Pacific by 2100. More rainfall is projected during summer months, with likelihood of more frequent heavy rainfall events. All models simulated a broad rainfall maximum stretching across the South Pacific Convergence Zone (SPCZ) and Intertropical Convergence Zone (ITCZ), but not all models resolved a rainfall minimum between these two regions. Problem with simulating the spatial structure of the Madden Julian Oscillation (MJO) resulting in tendencies for the convective anomaly to split into double ITCZs in the Pacific
Future trends Sea levels: likely to continue to rise, within global range of 0.19 to 0.58 cm/yr. The number of intense cyclones is likely to increase, though the total number of cyclones overall may decrease on a global scale. Max tropical cyclone wind intensity: could go up by 5 to10% by ~ 2050.
Scaling problems Since AOGCMs do not have sufficiently fine resolutions to see the islands, the projections are given over ocean surfaces rather than over land and very little work has been done in downscaling these projections to individual islands. Assessments also are made difficult because some climate processes are still not well understood, such as ENSO, MJO, IPO in the case of the South Pacific.
Box 16.1: Range of Future Impacts and Vulnerabilities in Small Islands
Region and System at Risk 6. Pacific and Mediterranean Sim Weed (Chromolaena odorata) 7.Tropical and Sub-tropical small islands: Coral reefs 8. Pacific small islands: Coastal erosion, water resources and human settlement 9. Pacific (Fiji): Tourism Box 16.1: Range of Future Impacts and Vulnerabilities in Small Islands Scenario and Reference None (CLIMEX model) Kriticos et al., 2005 A2 and B2 Donner et al., 2005 A2 and B2 World Bank, 2000 None (Survey) Becken, 2005. Changed Parameters Increase in moisture, cold, heat & dry stress Projected thermal stress, Climate sensitivity of 3.0 o C (2xCO2) Changes in temperature and rainfall, and sealevel rise Increased frequency and severity of extreme events Impacts and Vulnerability Pacific Islands at risk of invasion by sim weed Mediterranean semiarid and temperate climates predicted to be unsuitable to invasion. Bleaching could become annual or bianual event for vast majority of world s coral reefs in next 30-50 years without increase in thermal tolerance of 0.2 o C to 1.0 o C per decade Accelerated coastal erosion, saline intrusion into freshwater lenses and increased flooding from the sea cause large effects on human settlements. Less rainfall coupled with accelerated sea-level rise compound the threat on water resources; a 10 percent reduction in average rainfall by 2050 is likely to correspond to a 20 percent reduction in the size of the freshwater lens on Tarawa Atoll, Kiribati. Tourism highly vulnerable to climate change. Degradation of natural systems, e.g. coral reefs & forests further impacted by climate change
Box 16.7: Capacity Building for Development of Adaptation Measures in Small Islands: a Community Approach Capacity-building for development of adaptation measures in Pacific island countries uses a Community Vulnerability and Adaptation Assessment and Action approach. Such an approach is participatory, aims to better understand the nature of community vulnerability, and identifies opportunities for strengthening the adaptive capacity of communities. It seeks to promote a combination of bottom-up and top-down mechanisms to implementation, and supports the engagement of local stakeholders at each stage of the assessment process. If successful, this should enable integration or mainstreaming of adaptation into national development planning and local decision-making processes. Pilot projects in Samoa, Vanuatu and Cook Islands.
Box 16.4: Future Island Condition and Well-Being: The Value of Adaptation