1. Emission metrics inferred from regional aerosol perturbations
by Apostolos Voulgarakis,
Department of Physics, Imperial College London
PDRMIP Meeting, London, 12th of May 2017
Acknowledgements: Carlo Corsaro1, Peter Steiglechner1,2, Mathew Kasoar1, Alyssa Gilbert1, Dilshad Shawki1, Laura Mansfield1,3
(+thanks to the Met Office for computing resources)
1Imperial College London, UK, 2FAU Erlangen-Nuremberg, Germany, 3University of Reading, UK

2. Emission metrics
Climate policy makers use metrics to evaluate and compare pollutants in terms of their impacts on global warming.
Traditional metrics include the global warming potential (GWP), which is the only metric used in the Kyoto Protocol.
IPCC 2013

3. Global emission metrics
Temperature response due to a pulse of emission (i.e. iAGTP):
IPCC (2013)
- Global emission metrics have been used widely and been valuable for climate policy.

4. Motivation Can we develop metrics that:
Provide information on both global and regional climate impacts of emissions from specific locations of the globe?
Go beyond just warming, capturing multiple environmental impacts of air pollutant emissions, such as on rainfall and air quality in addition to temperature?
-> Global composition-climate modelling is now in the position to help explore such possibilities.

5. Past work on regional metrics
Collins et al. (2013)
[Also Aamaas et al. (2016)
& Aamaas et al. (in review)]
Novel and useful analysis. Though a two-step approach, and using regional
climate sensitivities from zonal rather than regional forcing perturbations.

6. Regions where emissions where perturbed
SO2

7. US EU China SW Flux Temperature Precipitation
Kasoar et al. (2016 & in review)
Shawki et al. (in prep.)

8. Global impacts of regional emissions
See Grantham Institute policy Briefing note No 5:

9. Regional
impacts
(European
SO2)
(See Grantham policy Briefing note)

10. Regional
impacts
(European
BC)
(See Grantham briefing note)

11. Next steps that we took (this week!):
Included time-dependence in the metrics
Attempted to make the metrics more model-independent

22. Potential future work:
Conclusions:
Strong remote responses. Substantial variation by emission region, and large variation when it comes to the response region. Regional, multi-impact metrics are mecessary for summarising these effects.
First results show a good agreement with past two-step approach based on zonal perturbations.
Potential future work:
Perform uncertainty analysis.
Calculate such metrics with more models.
Include more pollutants in this framework.
Include time-dependence for precipitation & air quality.
Differences in models’ RF is potentially compounded by existing differences in models’ climate sensitivities