The IPCC Fourth Assessment on Climate Change 2007: Impacts, Adaptation and Vulnerability (IPCC 2007a) addressed three main issues: a) impacts of climate change which are observable now; b) future effects of climate change on different sectors and regions; and c) responses to such effects. The assessment included 12 key messages, which are summarized here.

We will probably overshoot our current climate targets, so policies of adaptation and recovery need much more attention, say Martin Parry, Jason Lowe and Clair Hanson.

Investment and Financial Flows to Address Climate Change Several recent studies have reported the costs of adapting to climate change, including for developing countries. They have similar-sized es...

Several recent studies have reported the costs of adapting to climate change, including for developing countries. They have similar-sized estimates and have been influential in United Nations (UN) negotiations aimed at tackling climate change. Our reassessment of one of these studies, which reports the UN Framework Convention on Climate Change (UNFCCC) approximations for 2030, suggests that they are likely to be substantial underestimates, for several reasons. First, some sectors have not been included in an assessment of cost (for example, ecosystems, energy, manufacturing, retailing, and tourism). In addition, some of the sectors that have been included have been only partially covered. Finally, the additional costs of adaptation have sometimes been calculated as “climate markups” against low levels of assumed investment. In some parts of the world low levels of investment have led to a current adaptation deficit, and this deficit will need to be made up by full funding of development, without which the funding for adaptation will be insufficient. Residual damages also need to be evaluated and reported because not all damages can be avoided due to technical and economic constraints. There is an urgent need for more detailed assessments of these costs, including case studies of costs of adaptation in specific places and sectors

Both emissions reduction and adaptation will need to be much stronger than currently planned if dangerous global impacts of climate change are to be avoided. June's UN talks in Bonn and July's G8 summit present opportunities for world leaders to face this challenge.