Sir

Cynthia Rosenzweig and colleagues have taken a critical step towards a global synthesis of biological and physical impacts attributable to climate change (Nature 453, 353–357; 2008). They have expanded the database used in the recent Fourth Assessment from the Intergovernmental Panel on Climate Change (IPCC). We feel there are still many more studies that could be compiled to improve geographical and ecosystem imbalances and to provide a more comprehensive overview. Given the resources and effort required to identify these, it is beyond the scope of a limited number of individuals.

Climate-change impacts are being reported in a burgeoning literature from every ocean and continent. It is now time to shift the emphasis from proving climate impacts to providing key support for adaptation science. This requires a publicly accessible global database to collate research into climate-change impacts research and to allow the scientific community and the IPCC to focus additional efforts on attribution and adaptation. Global cooperation and sharing model outputs have led to breakthroughs in understanding the climate system, as illustrated by the scientific community's assembling of the physical-science basis (IPCC working group I). We suggest the impacts community (working group II) should follow a similar path.

Just as the IPCC endorsed the Program for Climate Model Diagnosis and Intercomparison data repository for model projections, so could it endorse an impacts repository, with researchers able continuously to upload research results that can then be quality-assured by a verification panel. The panel could be selected on the basis of expertise across a range of disciplines, and the repository website hosted by an international body, such as the International Geosphere–Biosphere Programme. Similar global initiatives underline the value of such an approach. These include the Ocean Biogeographic Information System (set up by the Census of Marine Life) and GenBank (National Center for Biotechnology).

This approach would allow greater efficiency, transparency and completeness in the compilation process, facilitate rapid identification of knowledge gaps and allow broader, expert-driven quality control of the interpretation of biological, aquatic and terrestrial data. This pathway to transparency and rigorous global synthesis is critical for a potential Fifth Assessment Report and for a world relying on scientific guidance.