Climate-change predictions are fraught with uncertainty. To build meaningful models of temperature and sea-level changes throughout the 21st century, researchers contributing to the Intergovernmental Panel on Climate Change's (IPCC) Third Assessment Report produced a set of four storylines that qualitatively assess social, economic, cultural, and political climes throughout the 21st century. These are developed into quantitative greenhouse-gas emission models called the Special Report on Emissions Scenarios (SRES), which replaced the IS92 emissions scenarios devised for the IPCC's first assessment. More than 40 such situations were developed, but the groups creating them selected six illustrative examples for use in climate-change studies. They come from four interrelated scenario families- A1, A2, B1, and B2 which give different weights to economics, globalization, and emphasis on the environment but do not account for specific policies to limit greenhouse gas emissions or adapt to climate change.
- Compiled by Brendan A. Maher