QUEST GSI was led by Nigel Arnell (University of Reading) with co-investigators from the Universities of Aberdeen, Leeds, UEA, Edinburgh, Southampton, UCL, London School of Hygiene and Tropical Medicine, CEH and CEFAS.

A central aim of this project was to assess the global-scale impacts of climate change under a range of scenarios, across a number of sectors. A methodology was developed to construct scenarios from a range of climate models, representing changes under different emissions scenarios and fixed amounts of change in global mean temperature. Impacts were estimated across a range of sectors, including water resources, fluvial and coastal flooding, crop productivity and food security, ecosystem productivity and human health, at regional and global scales.

The project has provided quantitative information on these impacts and their distribution across the world. The general conclusions are that impacts may be significant at relatively low levels of climate change, that estimates of impact in some sectors are very uncertain due largely to uncertainty in projected changes in rainfall (particularly in south Asia), that there are no obvious thresholds for step changes in impact that are consistent across region and sector, and that socio-economic conditions may amplify or reduce impacts, depending on context.

A second project aim was to develop the methodology in such a way that it could be readily applied to estimate impacts under other climate scenarios representing for example specific policy objectives. With additional funding from other sources, the project methodology has been applied successfully to estimate the impacts avoided by a set of feasible emissions policies.