Particles and Soot Connecting Climate Change and Airpollution Abatement

The climate abatement negotiations are based on the assumption that a doubling of the natural CO2 concentrations (2xCO2) will give 20C increases in global temperature. In the debate concerning the uncertainties in the climate models concerns have been raised that the climate warming will be considerably larger at 2xCO2. On the other hand soot has been suggested to cause a considerable fraction of the observed global warming indicating that the climate sensitivity to higher CO2 concentrations is lower than anticipated (Ramanathan and Carmichael, 2008). Another complicating factor is the climate cooling by atmospheric particles is still quite uncertain as indicated by IPCC (2007) giving a range of 0.5 to 2 W/m for the total anthropogenic aerosol forcing. The climate cooling hides the actual warming by climate warming components as soot, ozone and other greenhouse gases. Further complications are the feedback processes in the interaction between e.g. the atmosphere, the hydrosphere and the biosphere.