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The IPCC’s Fifth Assessment Report: What’s in it for Small Island Developing States

The IPCC offers some specific messages about the impacts of climate change on small island states – and some of its general findings on climate change adaptation and mitigation are of particular relevance to Small Island Developing States (SIDS)


The Intergovernmental Panel on Climate Change (IPCC) has produced the most comprehensive assessment of climate change ever. The Fifth Assessment Report, which the IPCC is releasing in four parts between September 2013 and November 2014, is the work of 830 expert authors, from 85 countries. Its first three volumes already stretch to 5,000+ pages.

Now the Climate and Development Knowledge Network and Overseas Development Institute have released a succinct guide to the assessment for decision-makers in Small Island Developing States (SIDS).

The IPCC’s Fifth Assessment Report: What’s in it for Small Island Developing States? distils the richest material on climate impacts and trends in small islands, and SIDS’ experiences in adaptation and mitigation from the thousands of pages of the Fifth Assessment Report and complemented with similar, peer reviewed case studies from such countries. The IPCC’s Fifth Assessment Report: What’s in it for Small Island Developing States? aims to make the IPCC’s important material more accessible and usable and responds to wide demand for this type of information.

The guide is part of a suite of materials to promote the key findings of the IPCC’s Fifth Assessment Report, which include companion volumes for Africa and South Asia. Please visit for the publications and a range of communications resources, including free-to-use images and infographics.

How does the IPCC’s Fifth Assessment Report define scientific certainty?

The IPCC assigns a degree of certainty to each key finding based on the type, amount, quality, and consistency of evidence (e.g., data, theory, models, expert judgment), and the degree of agreement among scientists. The terms to describe evidence are: limited, medium or robust; and to describe agreement: low, medium or high.

When the Fifth Assessment Report talks about ‘confidence’ in a finding, the level of confidence derives from a synthesis of the evidence that exists and the degree of scientific agreement on what the evidence means. The levels of confidence IPCC assigns are: very low, low, medium, high and very high.

IPCC describes the likelihood or certainty of an outcome having occurred or occurring in the future in terms of percentages:

  • Virtually certain 99% or more
  • Extremely likely 95% or more
  • Very likely 90% or more
  • Likely 66% or more More likely than not more than 50%
  • About as likely as not 33–66%
  • Unlikely 33% or less
  • Very unlikely 10% or less
  • Extremely unlikely 5% or less
  • Exceptionally unlikely 1% or less

On this scale, the world’s leading climate scientists consider it extremely likely that human activities have been the dominant cause of observed warming. Scientists consider 95% confidence as the ‘gold standard’, the standard at which theories are accepted as valid. For example, the theory of evolution, the theory on the age of the Earth, and the Big Bang theory all meet this standard of scientific confidence.

It is notable that the IPCC’s Fifth Assessment Report finds high levels of confidence and robust agreement for many of the impacts of climate change on small islands – in contrast to the agreement and confidence levels for many other developing regions.

Key messages

  1. The climate is already changing and SIDS are already feeling the impacts
  2. Further climate change is inevitable in the coming decades
  3. Climate change is affecting SIDS’ growth and development
  4. Climate change poses an existential threat to some SIDS
  5. Adaptation can reduce the impacts of climate change, but there are limits and risks involved
  6. The economic cost of adaptation to climate change is high in SIDS relative to the size of their economies
  7. SIDS stand to benefit from further integration of climate adaptation, mitigation and development approaches
  8. Transformation to a low-carbon economy implies new patterns of investment
  9. International cooperation is vital to avert dangerous climate change and SIDS governments can promote ambitious global action

Suggested citation

CDKN., 2014. The IPCC’s Fifth Assessment Report: What’s in it for Small Island Developing States.

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