File:IPCC Scenarios for 2100.png

From Global Warming Art



This figure summarizes some of the key variations amongst the six illustrative scenarios used by the Intergovernmental Panel on Climate Change (IPCC) in considering possible future emissions of greenhouse gases during the 21st century.

Key to table elements:

  • Population - The projected population in 2100, in billions (109).
  • Income - The projected per capita income in 2100 in thousands of US dollars relative to 1990 (i.e. not including inflation).
  • Energy Use - Total primary energy use in 2100, in 1018 Joules per year.
  • Cumulative CO2 - Total man-made carbon dioxide emissions between 1990 and 2100, in gigatonnes (1012 kg) of carbon (GtC)
  • Distribution Efficiency - The percentage of primary energy in 2100 that is available to end users after losses associated with energy conversion and distribution.
  • Fossil Fuel Portion of Energy Use - This is the percentage of primary energy in 2100 supplied by fossil fuel sources.

The IPCC divides their scenarios into 4 "storylines": A1, A2, B1, and B2. Each scenario is assumed to represent a plausible course of development of the world during this century, with the different scenarios marking different possible ways in which economic, political, social and environmental progress will be made within and across the various regions of the world. For the purpose of creating emissions scenarios as a result of this development, the IPCC assumes that no intentional action is taken in response to global warming. In this sense, each scenarios represents a vision of the world that might occur if global warming were not a factor; however, the B1 and B2 scenarios do presume a more environmentally aware world with an increased concern for sustainable development.


"The A1 storyline is a case of rapid and successful economic development, in which ... current distinctions between 'poor' and 'rich' countries eventually dissolve. The primary dynamics are:

  • Strong commitment to market-based solutions.
  • High savings and commitment to education at the household level.
  • High rates of investment and innovation in education, technology, and institutions at the national and international levels.
  • International mobility of people, ideas, and technology."


  • A1B is characterized by "'balanced' progress across all resources and technologies from energy supply to end use, as well as 'balanced' land-use changes".
  • A1T is characterized by "a 'non-fossil' future, with rapid development of solar and nuclear technologies on the supply side and mini-turbines and fuel cells used in energy end-use applications."
  • A1FI is characterized by aggressive exploitation of fossil fuel resources, combined with the development of pollution controls and technologies to eliminate pollution not associated with greenhouse gases.


"The A2 scenario family represents a differentiated world. ... Economic growth is uneven and the income gap between now-industrialized and developing parts of the world does not narrow... People, ideas, and capital are less mobile so that technology diffuses more slowly than in the other scenario families. International disparities in productivity, and hence income per capita, are largely maintained or increased in absolute terms. With the emphasis on family and community life, fertility rates decline relatively slowly, which makes the A2 population the largest among the storylines."


"The central elements of the B1 future are a high level of environmental and social consciousness combined with a globally coherent approach to a more sustainable development. ... [G]overnments, businesses, the media, and the public pay increased attention to the environmental and social aspects of development. Technological change plays an important role. ... Economic development ... is balanced, and efforts to achieve equitable income distribution are effective. ... [The] world invests a large part of its gains in improved efficiency of resource use ('dematerialization'), equity, social institutions, and environmental protection."


"The B2 world is one of increased concern for environmental and social sustainability compared to the A2 storyline. Increasingly, government policies and business strategies at the national and local levels are influenced by environmentally aware citizens, with a trend toward local self-reliance and stronger communities. International institutions decline in importance, with a shift toward local and regional decision-making structures and institutions. Human welfare, equality, and environmental protection all have high priority, and they are addressed through community-based social solutions in addition to technical solutions, although implementation rates vary across regions."


These scenarios lead to predictions for the greenhouse gas emissions during the 21st century and their expected concentrations in the atmosphere.

Carbon dioxide scenarios
Methane scenarios
Nitrous oxide scenarios


This figure was created by Robert A. Rohde from data published in the IPCC Special Report on Emissions Scenarios.

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current07:28, 6 November 2006Thumbnail for version as of 07:28, 6 November 2006550×622 (21 KB)Robert A. Rohde (Talk | contribs)