| Discount Rate and Statistic | ||||
|---|---|---|---|---|
| Emissions Year |
5% Average |
3% Average |
2.5% Average |
3% 95th Percentile |
| 2020 | 5800 | 18000 | 27000 | 48000 |
| 2025 | 6800 | 21000 | 30000 | 54000 |
| 2030 | 7800 | 23000 | 33000 | 60000 |
| 2035 | 9000 | 25000 | 36000 | 67000 |
| 2040 | 10000 | 28000 | 39000 | 74000 |
| 2045 | 12000 | 30000 | 42000 | 81000 |
| 2050 | 13000 | 33000 | 45000 | 88000 |
While point estimates are important for providing analysts with a tractable approach for regulatory analysis, they do not fully quantify uncertainty associated with the SC-GHG estimates. Figures ES-1 through ES-3 present the quantified sources of uncertainty in the form of frequency distributions for the SC-GHG estimates for emissions in 2020. The distributions of SC-GHG estimates reflect uncertainty in key model parameters chosen by the IWG such as the equilibrium climate sensitivity, as well as uncertainty in other parameters set by the original model developers. To highlight the difference between the impact of the discount rate and other quantified sources of uncertainty, the bars below the frequency distributions provide a symmetric representation of quantified variability in the SC-GHG estimates for each discount rate. There are other sources of uncertainty that have not yet been quantified and are thus not reflected in these estimates. When an agency determines that it is appropriate to conduct additional quantitative uncertainty analysis, it should follow best practices for probabilistic analysis.[1] The full set of information that underlies the frequency distributions in Figures ES-1 through ES-3 is available on OMB’s website[2].
- ↑ See e.g. OMB’s Circular A-4, section on Treatment of Uncertainty. Available at: https://www.whitehouse.gov/sites/whitehouse.gov/files/omb/circulars/A4/a-4.pdf.
- ↑ Available at https://www.whitehouse.gov/omb/information-regulatory-affairs/regulatorymatters/#scghgs
