Objective Problems to be solved.In order to quantify the potential climate impact of changing atmospheric constituents such as "greenhouse gases" two simple measures have been used, namely "Global Warming Potential" (GWP) and "Radiative Forcing" (RF). These measures are convenient "metrics" allowing estimation of potential climate change in terms of e.g. global mean temperatures from an emission into the atmosphere of greenhouse gases. It has recently been found, however, that these metrics have shortcomings, in particular when considering short lived, chemically active and not well mixed chemical species.Scientific objectives and approachThe objectives are to assess current metrics of climate change e.g. Radiative Forcing and Global Warming Potential as used in the Kyoto Protocol, to refine metrics of climate change suitable for climate forcing agents arising from inhomogeneously distributed perturbations of the atmosphere e.g. aerosols, ozone, contrails and from gases with different levels of thermal infrared optical thickness and different atmospheric adjustment times e.g. CO2 versus CH4 and to evaluate the refined metrics with respect to their usefulness for policy makers. Several cases of localised emission perturbations of ozone precursors will be defined. Using two different chemical transport models, the indirect impact on ozone and other greenhouse gases (e.g. methane) will be calculated and radiative forcing will be determined. Idealised and realistic cases of perturbations of climate change agents will be defined. The equilibrium climate responses to these forcings will be compared using three different general circulation models, and the causes of disagreement will be analysed. A review of available metrics of climate change will be made. Available metrics (like radiative forcing and global warming potential) will be applied to the simulations. Finally, on this basis it will be assessed in which cases the current metrics are sufficiently good predictors of climate change. Refined metrics will be developed and it will be assessed under which circumstances metrics are good predictors of climate change. The requirements of policy makers for metrics of climate change will be discussed and formulated. Current and refined metrics will be assessed with respect to their applicability as tools for decision making.Expected impactsThe project will contribute to a further development of environmentally effective policy measures under e.g. the UNFCCC and to better control and regulation of anthropogenic impact on the atmosphere and climate. Fields of science natural scienceschemical sciencesorganic chemistryaliphatic compoundsnatural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changes Programme(s) FP5-EESD - Programme for research, technological development and demonstration on "Energy, environment and sustainable development, 1998-2002" Topic(s) 1.1.4.-2. - Key action Global Change, Climate and Biodiversity Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator GERMAN AEROSPACE CENTRE EU contribution No data Address Muenchener Strasse 20, Oberpfaffernhofen 82234 WESSLING Germany See on map Total cost No data Participants (4) Sort alphabetically Sort by EU Contribution Expand all Collapse all CENTER FOR INTERNATIONAL CLIMATE AND ENVIRONMENTAL RESEARCH OSLO Norway EU contribution No data Address Blindern 0318 OSLO See on map Total cost No data CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE France EU contribution No data Address 10-12,Boulevard Vauban, 47 78047 GUYANCOURT See on map Total cost No data UNIVERSITY OF READING United Kingdom EU contribution No data Address Earley Gate 2, Whiteknights RG6 6BB READING / SILCHESTER See on map Total cost No data WUPPERTAL INSTITUTE FOR CLIMATE, ENVIRONMENT AND ENERGY Germany EU contribution No data Address 19,Doeppersberg 19 42103 WUPPERTAL See on map Total cost No data