1. The changing ozone depletion potential of N2O in a future climate
Laura Revell1,2, Fiona Tummon2, Ross Salawitch3,
Andrea Stenke2, and Thomas Peter2
1Bodeker Scientific, New Zealand,
2Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland
3Department of Atmospheric and Oceanic Sciences, University of Maryland, US
Revell et al., GRL, 2015, doi: /2015GL065702

2. Increasing CO2 and CH4 lead to less N2O-induced ozone destruction
x x x
Rate of NOx-induced ozone loss
(10-14 molecules s-1)
CH4 (ppb)
x x x
Results from the
SOCOL chemistry-
climate model:
9 year 2100 time-slice simulations based on RCP 6.0
x x x
CO2 (ppm)

3. Increasing CO2 and CH4 lead to less N2O-induced ozone destruction
x x x
Rate of NOx-induced ozone loss
(10-14 molecules s-1)
CH4 (ppb)
x x x
x x x
More CH4:
OH + NO2 + M → HNO3 + M
CO2 (ppm)

4. The ODP of N2O is sensitive to CO2 and CH4 concentrations
8.5
CH4 (ppb)
Year 2100 ODPN2O
6.0
4.5
2.6
CO2 (ppm)

5. The ODP of N2O is sensitive to CO2 and CH4 concentrations
8.5
Year 2000 ODPN2O
0.015
SOCOL
0.017
Ravishankara
et al., 2009
0.019
Daniel et al., 2010; Fleming et al., 2011
CH4 (ppb)
Year 2100 ODPN2O
6.0
4.5
2.6
CO2 (ppm)

6. The ODP of N2O is sensitive to CO2 and CH4 concentrations
8.5
Year 2000 ODPN2O
0.015
SOCOL
0.017
Ravishankara
et al., 2009
0.019
Daniel et al., 2010; Fleming et al., 2011
CH4 (ppb)
Year 2100 ODPN2O
Year 2100 ODPN2O
RCP 2.6
0.024
RCP 4.5
0.022
RCP 6.0
0.019
RCP 8.5
0.016
6.0
4.5
2.6
CO2 (ppm)

7. The ODP of N2O is sensitive to CO2 and CH4 concentrations
8.5
Year 2000 ODPN2O
0.015
SOCOL
0.017
Ravishankara
et al., 2009
0.019
Daniel et al., 2010; Fleming et al., 2011
???
CH4 (ppb)
Year 2100 ODPN2O
Year 2100 ODPN2O
RCP 2.6
0.024
RCP 4.5
0.022
RCP 6.0
0.019
RCP 8.5
0.016
6.0
4.5
2.6
CO2 (ppm)

8. The resulting change in global-mean total
ODPs for N2O quantify ozone loss due to N2O, relative to ozone loss due to CFC-11
ODP N2O = m CFC11 × τ N2O × ∆ μ CFC11 ×[∆ O 3 ] N2O m N2O × τ CFC11 × ∆ μ N2O ×[∆ O 3 ] CFC11
Molecular mass
Atmospheric
lifetime
Prescribed
change in
the surface
mixing ratio
The resulting change in global-mean total
column ozone

9. The resulting change in global-mean total
ODPs for N2O quantify ozone loss due to N2O, relative to ozone loss due to CFC-11
ODP N2O = m CFC11 × τ N2O × ∆ μ CFC11 ×[∆ O 3 ] N2O m N2O × τ CFC11 × ∆ μ N2O ×[∆ O 3 ] CFC11
Molecular mass
Atmospheric
lifetime
Prescribed
change in
the surface
mixing ratio
The resulting change in global-mean total
column ozone

10. Rate of chlorine-induced ozone loss
Chlorine-induced ozone destruction slows with increasing CH4 and decreasing CO2
CH4 (ppb)
Rate of chlorine-induced ozone loss
(10-14 molecules s-1)
More CH4:
CH4 + Cl → CH3 + HCl
CO2 (ppm)

11. Difference in rate of chlorine-induced ozone loss due to CO2 (%)
The effect of CO2 on chlorine-induced ozone destruction varies with location
Pressure (hPa)
Difference in rate of chlorine-induced ozone loss due to CO2 (%)
Latitude (°)

12. Uncertainties in atmospheric composition lead to ODPs for N2O differing by up to a factor of two
CH4 (ppb)
Year 2100 ODPN2O
CO2 (ppm)

13. To conclude:
N2O-induced ozone loss
N2O-induced ozone destruction slows with larger CO2 and CH4 concentrations.
CH4
CO2

14. To conclude:
N2O-induced ozone loss
N2O-induced ozone destruction slows with larger CO2 and CH4 concentrations.
CH4
CFC-11-induced ozone loss
CO2
CFC-11-induced ozone loss slows with larger CH4 and smaller CO2 concentrations.
CH4
CO2

15. To conclude:
N2O-induced ozone loss
N2O-induced ozone destruction slows with larger CO2 and CH4 concentrations.
CH4
CFC-11-induced ozone loss
CO2
CFC-11-induced ozone loss slows with larger CH4 and smaller CO2 concentrations.
CH4
ODPN2O
CO2
CH4
Uncertainties in atmospheric composition lead to a wide spread of values for the ODP of N2O.
CO2