The effectiveness of N2O in depleting stratospheric ozone

• Published in: Geophysical research letters Vol. 39; no. 15; pp. L15806 - n/a
• Main Authors: Revell, Laura E., Bodeker, Greg E., Smale, Dan, Lehmann, Ralph, Huck, Petra E., Williamson, Bryce E., Rozanov, Eugene, Struthers, Hamish
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 16.08.2012; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Atmosphere; Atmospheric chemistry; Atmospheric sciences; Carbon dioxide; CCM; Chlorine; Climate change; Climate models; Earth; Earth sciences; Earth, ocean, space; Emissions; Exact sciences and technology; Nitrous oxide; NOx; Oxygen; Ozone; Ozone depletion; Stratosphere; depletion; Carbon dioxide; concentration; cycles; Climate models; climate; ozone; chlorine; greenhouse gas; cooling; atmospheric circulation; Nitrogen dioxide; Nitrogen protoxide; oxygen; stratosphere
• DOI: 10.1029/2012GL052143
• ISSN: 0094-8276; 1944-8007

Recently, it was shown that of the ozone‐depleting substances currently emitted, N2O emissions (the primary source of stratospheric NOx) dominate, and are likely to do so throughout the 21st century. To investigate the links between N2O and NOx concentrations, and the effects of NOxon ozone in a changing climate, the evolution of stratospheric ozone from 1960 to 2100 was simulated using the NIWA‐SOCOL chemistry‐climate model. The yield of NOx from N2O is reduced due to stratospheric cooling and a strengthening of the Brewer‐Dobson circulation. After accounting for the reduced NOx yield, additional weakening of the primary NOxcycle is attributed to reduced availability of atomic oxygen, due to a) stratospheric cooling decreasing the atomic oxygen/ozone ratio, and b) enhanced rates of chlorine‐catalyzed ozone loss cycles around 2000 and enhanced rates of HOx‐induced ozone depletion. Our results suggest that the effects of N2O on ozone depend on both the radiative and chemical environment of the upper stratosphere, specifically CO2‐induced cooling of the stratosphere and elevated CH4 emissions which enhance HOx‐induced ozone loss and remove the availability of atomic oxygen to participate in NOx ozone loss cycles. Key Points NOx‐induced ozone destruction slows through the 21st century Due to chemical, radiative and dynamical changes in the stratosphere The effectiveness of N2O as an ODS is weakened by elevated CH4 concentrations