Global and regional greenhouse gas emissions scenarios

This article presents a set of 30 greenhouse gas (GHG) emissions scenarios developed by six modeling teams. The scenarios describe trajectories up to 2100 by four world regions. Today the distribution of both income and GHG e missions is very unbalanced between various world regions. Furthermore, the relative importance of individual gases and sources of emission differ fro m region to region. A feature shared by all scenarios is higher growth rate s of population, income and GHG emissions in the current developing countri es (DEV) than in industrialized countries (IND). Today the DEV regions acco unt for about 46% of all emissions, but by 2100 no less they contribute 67- 76% of the global total. By that same year the total income generated in th e DEV regions reaches 58-71% from only 16% in 1990. As a result of these tw o developments, GHG emissions per unit of income converge over time. Carbon emitted from fossil fuel use remains the primary source of GHG emissions o ver the next century; by 2100 CO2 makes up 70 to 80% of total GHG emissions . The role of sulfur warrants special attention. Contrary to many earlier s tudies, all scenarios presented here assume that sulfur emissions are contr olled in all regions sooner or later, and to various degrees. As sulfur pla ys a role in cooling of the atmosphere through formation of sulfate aerosol s, a local effect, this abatement constitutes a relative local warming effe ct. The decrease of sulfur emissions is already observed the IND regions, a nd is expected also in ASIA after an initial rise. (C) 2000 Elsevier Scienc e Inc.