1. Detlef van Vuuren 1 Scenario analysis on the interaction betweeen climate and air pollution policy

2. Starting point: Critique on RCPs  Thruth: The are not too optimistic – but do not cover counterfactual or pessimistic scenarios SO 2 emissions NOx emissions RCPs were critiqued by the atmospheric modeling community for being to optimistic on air pollution Can we develop a set of scenarios relevant for both climate and air pollution analysis? Based on most recent inventories?

3. PEGASOS scenario analysis  In PEGASOS two tools to create scenarios: –RAINS (Short-term, Europe) –IMAGE (Long-term, World)  Policies introduced do not address biomass- burning emissions Climate policy No policy Stringent policy No policyStringent policy Air pollution policy RCP 6.0 - FRZ RCP 2.6 - FRZ RCP 6.0 - CLE RCP 6.0 MFR RCP 2.6 - CLE RCP 2.6 MFR RCP 6.0 - KTZ RCP 2.6 - KTZ Two key determinants of future emissions are future climate and air pollution policies

4.  Significant co-benefits of climate policy on future air pollution emissions globally  Less strong in regions with already stringent policy  Different for different air pollutants NO x PEGASOS scenario analysis Climate policy No policy Stringent policy No policyStringent policy Air pollution policy How will future climate and air policy influence air pollution?

5. 2005 2050 Co-benefit NO x PEGASOS scenario analysis Climate policy No policy Stringent policy No policyStringent policy Air pollution policy  Significant co-benefits of climate policy on future air pollution emissions globally  Less strong in regions with already stringent policy  Different for different air pollutants How will future climate and air policy influence air pollution?

6. 5 juni 2016 6 NO x PEGASOS scenario analysis Climate policy No policy Stringent policy No policyStringent policy Air pollution policy 2005 2050

7. PEGASOS scenario analysis  Level of co-benefits depends on type of air pollution: important for SO2 but less so for VOC  Same amount of reductions possible via different routes  For some component policy response becomes “saturated” Climate policy Air pol. policy Both High emissions Low emissions CO2 emissions % bl Air pollution emissions % bl

8. 5 juni 2016 8 2005 2050 NO x PEGASOS scenario analysis Climate policy No policy Stringent policy No policyStringent policy Air pollution policy  For BC, OC some emissions sources (biomass burning) are unabated.  As a result : convergence at certain emission levels. How will future climate and air policy influence air pollution?

9. PEGASOS scenario analysis Climate policy No policyStringent policy No policy Stringent policy Air pollution policy 2005 Climate and air pollution policy can reduce ozone concentrations globally

10. PEGASOS scenario analysis Climate policy No policyStringent policy No policy Stringent policy Air pollution policy Trade-off for SO2 control; substantially reduced for stringent climate policy MAGICC model calculations How will currently planned air quality regulations affect climate?

11. Comparison EDGAR, IMAGE, GAINS  Scenarios show a reasonably good fit 5 juni 2016 11 VOC CO SO2 NOx

12. Shared Socio-economic pathways (SSPs)… “PEGASOS” inside Strong Weak Forcing level (W/m 2 ) 8.5 6.0 4.5 2.6 SSP1SSP2SSP3 Shared Socio-economic Pathways SSP4SSP5

13. SSPs include wider range of emissions 200020202040206020802100 Emissions|Sulfur 0 20 40 60 80 100 120 140 160 AIM/CGE GCAM IMAGE MESSAGE-GLOBIOM REMIND-MAGPIE SSP1 SSP2 SSP3 SSP4 SSP5 WITCH-GLOBIOM 200020202040206020802100 Emissions|Sulfur 0 20 40 60 80 100 120 140 160 Baseline 450/2.6

14. 5 juni 2016 14 Optimal strategies of GHG emission reduction  CO 2 emissions hardly affected (and thus also co- benefits)  CH4 sensitive to choice of metric if changing from GWP 20, GWP 100, GWP 500 or GTP Impact of different metrics

15. In the PEGASOS project, we produced a range of air pollution emission scenarios to look into synergies and trade-offs. Multiple emission scenarios indicate scope for further improvements of air quality, either via air pollution control, climate policy or both. Important to look at synergies and trade-offs. Results depend strongly on air pollution component and region. The consequences of implementing globally the currently maximum feasible air pollution emission controls via changes in aerosols are in the order of ca. 0.3 °C warming worldwide over 20 years according to the simple MAGICC model.