Scenario A1
A rapidly growing and homogenizing world
The A1 storyline differs from the others in that it is divided into three subscenarios that assume different sources of energy. A1FI assumes a fossil-fuel intensive future, in which we continue to rely heavily on fossil fuels. A1T assumes a transition to alternative forms of fuel, and A1B assumes an intermediate scenario between abandoning or relying completely on fossil fuels.
This scenario paints a world with rapid growth and globalization and includes the following changes over the next century:
- Very rapid economic growth
- Low population growth
- Adoption of new and more efficient technology
- Significant reduction in (per capita) income between world regions
- Increased interaction between world regions, including cultural and social connections
Impacts vary widely
It's important to note that the impacts of the A1 scenarios vary greatly depending on the use of fossil fuels or alternative energy sources. The following table shows the estimate for greenhouse gas output in the A1 scenarios:
In cases in which we curtail or eliminate our reliance on fossil fuels, global yearly emissions of carbon dioxide (measured in gigatons) increase until about midcentury and then decline.
In the case in which we completely transition to alternative fuels, we can expect to see yearly emissions fall below 1990 levels.
However, in the case in which we continue our reliance on fossil fuels, we see yearly CO2 emissions increase substantially for most of the century before finally leveling off (though not decreasing) near the end of the century.
Temperature increases vary greatly
With these varying rates of greenhouse gas emissions, the three A1 scenarios also present very different levels of temperature change over the next century:
- A1FI: 4.3 to 11.5 degrees Fahrenheit
- A1B: 3.1 to 7.9 degrees Fahrenheit
- A1T: 2.5 to 6.8 degrees Fahrenheit
These increases will be felt differently through the world, with some regions seeing smaller increases and others seeing greater change.
More detailed information from the IPCC about the future world picture in the A1 scenarios can be found here.