Scenarios can also help to improve the understanding of key relationships among factors that drive future emissions. Developing scenarios for a period of one hundred years is a relatively new field. Within that period we might expect two major technological discontinuities, a major shift in societal values and a change in the balance of geopolitical power. Additionally, most databases do not go back much further than 50 years and many less than that. Scenarios can be used as an integration tool, allowing an equal role for intuition, analysis and synthesis.
Scenarios are pertinent, plausible, alternative futures.
Their pertinence, in this case, is derived from the need for climate change modellers to have a basis for assessing the implications of future possible paths for greenhouse gas emissions. Their plausibility is tested by peer review, in an open process, which includes their publication on the World Wide Web. There are clearly an infinite number of possible alternative futures to explore. The alternative futures constructed are not, and cannot be, value free since like any work they self-evidently reflect the team's view of the possible. The scenarios should not be construed as being desirable or undesirable in their own right and have been built as descriptions of possible, rather than preferred, developments.