Emission scenario
An emission scenario is a framework used to evaluate the potential future impacts of global greenhouse gas (GHG) emissions based on different narratives and assumptions. The Intergovernmental Panel on Climate Change (IPCC) utilizes these scenarios to analyze the science, impacts, and socio-economic aspects of climate change. Developed through a combination of literature reviews and expert feedback, these scenarios encompass emissions from diverse GHG sources and their driving factors. The Special Report on Emissions Scenarios (SRES) presents scenarios that incorporate various demographics, technologies, and economic developments, providing insights for international climate negotiations.
Each scenario is presented as a storyline reflecting distinct future possibilities, such as rapid economic growth paired with peak population or slower growth with a continuously increasing global population. While these scenarios serve as valuable tools for understanding climate dynamics and informing policy, they also face criticism for potentially overlooking climate-specific initiatives and inaccurately estimating future economic growth and emissions. Despite these critiques, emission scenarios remain widely used across the globe, highlighting their role in shaping the discourse on climate change and sustainable development.
Emission scenario
Definition
An emission scenario is a means of assessing the future impact of global greenhouse gas (GHG) emissions through different story lines that use a variety of assumptions. The Intergovernmental Panel on Climate Change (IPCC), established by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), uses various emission scenarios to periodically review the science, impacts, and socioeconomics of climate change. The IPCC developed the projected scenarios using a variety of sources including literature searches, alternative modeling approaches, and feedback from informed groups and individuals. These models include emissions from all types of GHGs and their driving forces.
Significance for Climate Change
The Special Report on Emissions Scenarios (SRES) allows a forward-looking assessment of the causes and impact of emissions as viewed from demographic, technological, and economic developments. Armed with information provided by the emission scenarios, the IPCC is able to advise the Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC). The SRES team included fifty members from eighteen countries representing a range of scientific disciplines. In order to provide the UNFCCC with useful information covering a variety of possibilities, the IPCC used forty different scenarios; each scenario makes different assumptions for future GHG pollution. Included in the report are assumptions about possible technological and future economic development for each scenario, as well as options to reduce the predicted environmental hazards.
The reports come in the form of story lines, with each story line representing a different future possibility. For example, one of the story lines allows for a future of rapid economic growth, advanced technologies and global population peaking in mid-century and then declining. Another story line presents continuously expanding global population with slower economic growth, while another assumes the introduction of cleaner, more efficient technologies that are environmentally friendly and assumes growth of service and information technologies. A fourth story line presents variations on the other three possible outcomes.
As with any attempt to divine the future, emission scenarios have their critics. The critics argue that the scenarios don’t include climate-specific initiatives and that they miss the mark on their assessment of economic growth and degree of future GHG emissions. For example, overestimating economic growth might point to higher GHG emissions than reality would suggest. Also, the scenarios do not assume implementation of the UNFCCC or the emissions targets of the Kyoto Protocol. However, emission scenarios are a useful tool used throughout the world, and many models exist independent of the IPPC model.