CLIMATE-CHANGE AND ENERGY-POLICY - THE IMPACTS AND IMPLICATIONS OF AEROSOLS

Anthropogenic increases in aerosol concentrations are believed to sign ificantly affect climate, notably by exerting a negative radiative for cing which counteracts, to some extent, the positive radiative forcing of greenhouse gases (GHGs). The potential effects of aerosols and the ir short atmospheric lifetimes raise issues which are critical to clim ate policy This paper isolates the implications of aerosols by treatin g aerosol emissions as a policy variable separate from GHG emissions, but Linked through energy policy, Using a simple climate model, result s show that with no GHG abatement, changes in aerosol emissions can si gnificantly affect net radiative forcing, but that the positive forcin g of GHGs continues to dominate, Aerosols are also shown to reduce the difference in net radiative forcing between abatement and 'business-a s-usual' policies, while the ability to reduce this effect through aer osol emissions from energy policy is limited, However, the conclusion that aerosols are beneficial to climate because they counteract greenh ouse warming is then questioned; scenarios with high aerosol and GHG e missions are expected to yield both greater uncertainty in mean temper ature and a greater likelihood of changes in other climate parameters. (C) 1997 Published by Elsevier Science Ltd. All rights reserved.