5.6 Costs of mitigation and long-term stabilisation targets
The macro-economic costs of mitigation generally rise with the stringency of the stabilisation target and are relatively higher when derived from baseline scenarios characterised by high emission levels. {WGIII SPM}
There is high agreement and medium evidence that in 2050 global average macro-economic costs for multi-gas mitigation towards stabilisation between 710 and 445ppm CO2-eq are between a 1% gain to a 5.5% decrease of global GDP (Table 5.2). This corresponds to slowing average annual global GDP growth by less than 0.12 percentage points. Estimated GDP losses by 2030 are on average lower and show a smaller spread compared to 2050 (Table 5.2). For specific countries and sectors, costs vary considerably from the global average. {WGIII 3.3, 13.3, SPM}
Table 5.2. Estimated global macro-economic costs in 2030 and 2050. Costs are relative to the baseline for least-cost trajectories towards different long-term stabilisation levels. {WGIII 3.3, 13.3, Tables SPM.4 and SPM.6}
| Stabilisation levels (ppm CO2-eq) | Median GDP reductiona (%) | Range of GDP reductionb (%) | Reduction of average annual GDP growth rates (percentage points) c,e |
|---|
| | 2030 | 2050 | 2030 | 2050 | 2030 | 2050 |
|---|
| 445 – 535d | Not available | < 3 | < 5.5 | < 0.12 | < 0.12 |
| 535 – 590 | 0.6 | 1.3 | 0.2 to 2.5 | slightly negative to 4 | < 0.1 | < 0.1 |
| 590 – 710 | 0.2 | 0.5 | -0.6 to 1.2 | -1 to 2 | < 0.06 | < 0.05 |