Special Report on Emissions Scenarios (SRES)

A report published by the IPCC which defined different future emissions pathways based on potential storylines for the future, including population, energy use etc.

In detail

UKCP09 provides users with future climate projections based on three emissions scenarios for the future based on SRES.

A1FI = high emissions scenario
A1B = medium emissions scenario
B1 = low emissions scenario

The SRES emissions scenarios assume no political intervention and are based on different assumptions about future socio-economic changes. No relative probability can be assigned to these scenarios but nor they should not be seen as equally probable.

• More information about the emissions scenarios that were used in the preparation of the UKCP09 projections is given in Section 3.2.13 of the UKCP09 Climate change projections report and in Annex 1. Further details about the uncertainties associated with emissions scenarios are provided in Section 2.4 of the UKCP09 Climate change projections report.

• One of the advances in UKCP09 is that realisations of time-dependent climate changes for the 21st century were obtained for all three emissions scenarios reported (SRES A1B1, B1 and A1FI), making the final results more robust than those presented in previous UK climate scenarios. However, constraints associated with the experimental design (such as that the discrepancy term for future projected variables was assumed to be the same for all three emissions scenarios as obtained using A1B1) mean that the results for B1 and A1FI are considered less robust than those for A1B1.

• It should be remembered that different UKCP09 data sources use one or more of these emissions scenarios. In addition, a High++ scenario has been developed to explore a high-end, very unlikely, scenario for sea level rise.

Find out more

• Nakićenović et al. (2000). Special Report on Emissions Scenarios 


• IPCC Fourth Assessment Report, Working Group 1 report The Physical Science Basis, Chapter 10