We all as professionals in the field of climate change have heard of the SRES Scenarios published by IPCC in 2000 for use in their Third Assessment Report. The whole idea behind constructing the SRES scenarios was to explore future developments in the global environment with special reference to the production of greenhouse gases and aerosol precursor emissions.
To stay in touch with the SRES scenarios, it is essential to keep in mind the following terminology:
- Storyline: a narrative description of a scenario (or a family of scenarios), highlighting the main scenario characteristics and dynamics, and the relationships between key driving forces.
- Scenario: projections of a potential future, based on a clear logic and a quantified storyline.
- Scenario family: one or more scenarios that have the same demographic, politico-societal, economic and technological storyline.
The narrative storylines defined by the SRES team are:
- A1
- A2
- B1
- B2
These narrative storylines are based on relationships between two major factors:
- Forces driving greenhouse gas and aerosol emissions
- Evolution during the 21st century for large world regions and globally
Each storyline represents different demographic, social, economic, technological, and environmental developments that diverge in increasingly irreversible ways.
To put it in simple words, the four storylines combine two sets of divergent tendencies: one set varying between strong economic values and strong environmental values, the other set between increasing globalization and increasing regionalization.
After determining the basic features of each of the four storylines, including quantitative projections of major driving variables such as population and economic development taken from reputable international sources (e,g, United Nations, World Bank and IIASA), the storylines were then fully quantified using integrated assessment models, resulting in families of scenarios for each storyline. In all 40 scenarios were developed by six modelling teams. All are equally valid, with no assigned probabilities of occurrence.
Six groups of scenarios were drawn from the four families: one group each in the A2, B1 and B2 families, and three groups in the A1 family, characterising alternative developments of energy technologies: A1FI (fossil intensive), A1T( predominantly non-fossil) and A1B (balanced across energy sources). Illustrative scenarios1 were selected by the IPCC to represent each of the six scenario groups.
The final and complete SRES scenario data can be viewed and downloaded following the link below: http://sres.ciesin.org/final_data.html
Sources: Nakicenovic, N. et al (2000). Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, U.K., 599 pp. Available online at: http://www.grida.no/climate/ipcc/emission/index.htm
