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Future Emissions

Box 2

The correlation between CO2 emissions and population size and energy use raises the question of what CO2 emissions may be like in the future. The IPCC examined this issue in depth, exploring a wide range of emissions and the forces underlying them. Six scenarios were then selected to illustrate the range of possible futures. The CO2 emissions associated with the six illustrative scenarios are shown in Figure 9 below.

Scenario Descriptors
A1 family: Global population peaks around 2050 and declines thereafter. New technologies are rapidly introduced and economic disparities between regions are substantially reduced. All scenarios in the A1 group use the same basic population, technology, and economic assumptions. They differ in assumptions about how energy is supplied. Three illustrative scenarios have been used:

A1FI - fossil fuels continue to supply most of the energy.
A1T - non-fossil fuel energy sources dominate.
A1B - energy supply is balanced among fossil fuel and non-fossil energy sources.

A2 family: Global population continues to increase throughout the 21st century. Disparities in economic growth of regions persist, and technological change occurs more slowly than in any of the other illustrative scenarios.

B1 family: Global population peaks around 2050 and declines thereafter. Economies rapidly become service and information oriented, income disparities decrease and non-fossil fuel energy technologies are introduced.

B2 family: Global population continues to increase throughout the 21st century but not as rapidly as in the A2 family. Economic growth is less rapid than in the B1 family and less concentrated in the energy, service or information sectors than in either B1 or A1. Decreases in economic disparities occur primarily at local and regional levels.

Figure 9

CO2 Emissions from the IPCC Emissions Scenarios