Intergovernmental Panel on Climate Change IPCC

The Intergovernmental Panel on Climate Change (IPCC) developed long-term emissions scenarios in 1990 and 1992. These scenarios have been widely used in the analysis of possible climate change, its impacts, and options to mitigate climate change.
In 1995, significant changes in the understanding of driving forces of emissions and methodologies have been made relating to the carbon intensity of energy supply, the income gap between developed and developing countries, and sulfur emissions.
Since then, a new set of scenarios has been developed.

What are the scenarios and what is their purpose?
Future greenhouse gas (GHG) emissions are the product of very complex dynamic systems, determined by driving forces such as demographic development, socio-economic development, and technological change. Scenarios are alternative images of how the future might unfold and are an appropriate tool with which to analyse how driving forces may influence future emission outcomes. They assist in climate change analysis, including climate modeling and the assessment of impacts, adaptation, and mitigation.

What are the main characteristics of the new scenarios?
A set of scenarios was developed to represent the range of driving forces and emissions to reflect current understanding and knowledge about underlying uncertainties.
Four different narrative storylines were developed to describe consistently the relationships between emission driving forces and their evolution. Each storyline represents different demographic, social, economic, technological, and environmental developments, which may be viewed positively by some people and negatively by others.
The scenarios cover a wide range of the main demographic, economic, and technological driving forces of GHG and sulfur emissions.
Furthermore government policies can, to varying degrees, influence the GHG emission drivers such as demographic change, social and economic development, technological change, resource use, and pollution management.