cc: gruebler@uea.ac.uk, m.hulme@uea.ac.uk date: Sat, 06 Dec 1997 17:03:12 +0100 from: Nebojsa NAKICENOVIC subject: Sulphate aerosol emissions to: Tim Carter Dear Tim, We are now working on new emissions scenarios, as Mike told you. They are not complete yet, the first pre-view should be available by April and final versions in early 1999. Arnulf is working of the literature assessment of sulfate aerosol emissions. He will forward you a copy of his most recent draft that we will be using to determine alternative sulfur emissions to go with new scenarios. As you will see, our current view is that older scenarios over-estimated sulfur emissions. They are going to be lower because of the need to protect against acidification, because of technological change in the energy system and because of the shift away from coal-intensive energy systems. Best regards, Naki >X-Sender: carter@popper.fmi.fi >Date: Fri, 05 Dec 1997 15:47:54 +0200 >To: naki@iiasa.ac.at >From: Tim Carter >Subject: Sulphate aerosol emissions > >Servus Naki, > >Just a quick enquiry about sulphate emissions. Mike Hulme reported to our >IPCC Task Group on Climate Scenarios in London in October some discussions >he had with you and others about the new IPCC emissions scenarios >(storylines, I believe they may be called). > >Although I realise that these are not available yet, one feature that Mike >reported was a considerable downward revision (relative to IS92a) of the >sulphate aerosol scenarios under all foreseeable futures. Since IS92a, or >something like it, was used to create the direct sulphate aerosol scenario >employed in several recent (1995-) coupled GCM runs, I would like to ask >what the latest opinion is about the concentrations assumed for 2050, >especially over east Asia. Mike suggested that the concentrations assumed in >the model runs were unrealistically high, to the extent of presenting a >potential toxic hazard. > >Do you know of any published article(s) that discusses this apparent >overestimation of the sulphate aerosol forcing? Unpublished will do, if it >is authoritative. > >Any thoughts would be much appreciated. > >Best regards to you and to all friends at IIASA. > >Tim > > >**************************************************** >Dr. Timothy Carter >Affiliation: Agricultural Research Centre of Finland >Postal address: c/o Finnish Meteorological Institute >Box 503, FIN-00101 Helsinki, FINLAND > >Tel: +358-9-1929-4125 >Fax: +358-9-1929-4129 >Email: tim.carter@fmi.fi >**************************************************** > > >