The tone of the report is serious but nuanced. Rather than fatalistically depicting future disasters, it depicts the “opportunity space” of pathways towards climate-resilient development.
Who is most at risk? According to the report, climate change impacts will most severely affect slum dwellers (especially in low-lying coastal regions), subsistence farmers, “first peoples” or indigenous people living in extreme-weather areas (for example, near the North and South Poles) and pastoralists who depend on marginal land. Geographically, the most vulnerable people are concentrated in Africa and Asia, and on small islands.
The report’s timing is opportune, because things need to come together in 2015. In December, the UN climate change summit in Lima, Peru will aim to pave the way to reaching a binding global agreement on efforts to tackle climate change at the subsequent summit in Paris, France. And a new set of global development goals is being designed, ready to start after 2015. A conference I chaired earlier this year concluded that these need to deliver for people in the least developed countries and small island states, whose livelihoods are most at risk. 
A rise in average global temperatures of four degrees Celsius or more could overwhelm development efforts. But UN University rector David Malone has suggested that the “catastrophist” tendency in development thinking — though understandable as a “fundraiser” — is unhelpful as it devalues the positive changes of the last 20 years. 
The IPCC’s new report records some such positive changes. For example, it reports that most African countries are working on governance systems for adaptation, including disaster risk management, climate-proofing infrastructure and technologies, and diversification of livelihoods. SciDev.Net also recently profiled local projects for sustainable development, called Nationally Appropriate Mitigation Actions, which could help developing countries reduce emissions voluntarily.
So how can we encourage such efforts? Thinking about past successful global initiatives, one may offer an answer. UNESCO’s big push on primary education (Education for All), launched in 1990, got many more children into school partly because of the principle that no country with a well-developed plan should lack the finance to implement it.
Could a similar principle be agreed by the time of the Paris summit? Then no sound national plan to address adaptation and mitigation would lack the finances for implementation. It would be an investment in our common future.
Roger Williamson is an independent consultant and visiting fellow at the Institute of Development Studies at the University of Sussex, United Kingdom. Previous positions include organising nearly 80 international policy conferences for the UK Foreign Office and being head of policy and campaigns at Christian Aid.