IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability

16.1 Introduction

While acknowledging their diversity, the IPCC Third Assessment Report (TAR) also noted that small island states share many similarities (e.g., physical size, proneness to natural disasters and climate extremes, extreme openness of their economies, low adaptive capacity) that enhance their vulnerability and reduce their resilience to climate variability and change.

Analysis of observational data showed a global mean temperature increase of around 0.6°C during the 20th century, while mean sea level rose by about 2 mm/yr, although sea-level trends are complicated by local tectonics and El Niño-Southern Oscillation (ENSO) events. The rate of increase in air temperature in the Pacific and Caribbean during the 20th century exceeded the global average. The TAR also found much of the rainfall variability appeared to be closely related to ENSO events, combined with seasonal and decadal changes in the convergence zones.

Owing to their high vulnerability and low adaptive capacity, small islands have legitimate concerns about their future, based on observational records, experience with current patterns and consequences of climate variability, and climate model projections. Although emitting less than 1% of global greenhouse gases, many small islands have already perceived a need to reallocate scarce resources away from economic development and poverty alleviation, and towards the implementation of strategies to adapt to the growing threats posed by global warming (e.g., Nurse and Moore, 2005).

While some spatial variation within and among regions is expected, the TAR reported that sea level is projected to rise at an average rate of about 5.0 mm/yr over the 21st century, and concluded that sea-level change of this magnitude would pose great challenges and high risk, especially to low-lying islands that might not be able to adapt (Nurse et al., 2001). Given the sea level and temperature projections for the next 50 to 100 years, coupled with other anthropogenic stresses, the coastal assets of small islands (e.g., corals, mangroves, sea grasses and reef fish), would be at great risk. As the natural resilience of coastal areas may be reduced, the ‘costs’ of adaptation could be expected to increase. Moreover, anticipated land loss, soil salinisation and low water availability would be likely to threaten the sustainability of island agriculture and food security.

In addition to natural and managed system impacts, the TAR also drew attention to projected human costs. These included an increase in the incidence of vector- and water-borne diseases in many tropical and sub-tropical islands, which was attributed partly to temperature and rainfall changes, some linked to ENSO. The TAR also noted that most settlements and infrastructure of small islands are located in coastal areas, which are highly vulnerable not only to sea-level rise (SLR) but also to high-energy waves and storm surge. In addition, temperature and rainfall changes and loss of coastal amenities could adversely affect the vital tourism industry. Traditional knowledge and other cultural assets (e.g., sites of worship and ritual), especially those near the coasts, were also considered to be vulnerable to climate change and sea-level rise. Integrated coastal management was proposed as an effective management framework in small islands for ensuring the sustainability of coastal resources. Such a framework has been adopted in several island states. More recently, the Organisation of Eastern Caribbean States (OECS, 2000) has adopted a framework called ‘island systems management’, which is both an integrated and holistic (rather than sectoral) approach to whole-island management including terrestrial, aquatic and atmospheric environments.

The TAR concluded that small islands could focus their efforts on enhancing their resilience and implement appropriate adaptation measures as urgent priorities. Thus, integration of risk reduction strategies into key sectoral activities (e.g., disaster management, integrated coastal management and health care planning) should be pursued as part of the adaptation planning process for climate change.

Building upon the TAR, this chapter assesses recent scientific information on vulnerability to climate change and sea-level rise, adaptation to their effects, and implications of climate-related policies, including adaptation, for the sustainable development of small islands. Assessment results are presented in a quantitative manner wherever possible, with near, middle, and far time-frames in this century, although much of the literature concerning small islands is not precise about the time-scales involved in impact, vulnerability and adaptation studies. Indeed, independent scientific studies on climate change and small islands since the TAR have been quite limited, though there are a number of synthetic publications, regional resource books, guidelines, and policy documents including: Surviving in Small Islands: A Guide Book (Tompkins et al., 2005); Climate Variability and Change and Sea-level rise in the Pacific Islands Region: A Resource Book for Policy and Decision Makers, Educators and Other Stakeholders (Hay et al., 2003); Climate Change: Small Island Developing States (UNFCCC, 2005); and Not If, But When: Adapting to Natural Hazards in the Pacific Island Region: A Policy Note (Bettencourt et al., 2006).

These publications rely heavily on the TAR, and on studies undertaken by global and regional agencies and contracted reports. It is our qualitative view that the volume of literature in refereed international journals relating to small islands and climate change since publication of the TAR is rather less than that between the Second Assessment Report in 1995 and the TAR in 2001. There is also another difference in that the present chapter deals not only with independent small island states but also with non-autonomous small islands in the continental and large archipelagic countries, including those in high latitudes. Nevertheless the focus is still mainly on the autonomous small islands predominantly located in the tropical and sub-tropical regions; a focus that reflects the emphasis in the literature.