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The Role of Natural Halogens in Global Tropospheric Ozone Chemistry and Budget Under Different 21st Century Climate Scenarios

Published version
Peer-reviewed

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Abstract

jats:titleAbstract</jats:title>jats:pTropospheric ozone (<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0001.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0001" />) is an important greenhouse gas and a surface pollutant. The future evolution of <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0002.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0002" /> abundances and chemical processing are uncertain due to a changing climate, socioeconomic developments, and missing chemistry in global models. Here, we use an Earth System Model with natural halogen chemistry to investigate the changes in the <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0003.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0003" /> budget over the 21st century following Representative Concentration Pathway (RCP)6.0 and RCP8.5 climate scenarios. Our results indicate that the global tropospheric <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0004.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0004" /> net chemical change (NCC, chemical gross production minus destruction) will decrease <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0005.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0005" />, notwithstanding increasing or decreasing trends in ozone production and loss. However, a wide range of surface NCC variations (from −60<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0006.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0006" /> to 150<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0007.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0007" />) are projected over polluted regions with stringent abatements in <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0008.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0008" /> precursor emissions. Water vapor and iodine are found to be key drivers of future tropospheric <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0009.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0009" /> destruction, while the largest changes in <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0010.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0010" /> production are determined by the future evolution of peroxy radicals. We show that natural halogens, currently not considered in climate models, significantly impact on the present‐day and future global <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0011.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0011" /> burden reducing <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0012.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0012" />30–35 Tg (11–15<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgrd57367-math-0013.png" xlink:title="urn:x-wiley:2169897X:media:jgrd57367:jgrd57367-math-0013" />) of tropospheric ozone throughout the 21st century regardless of the RCP scenario considered. This highlights the importance of including natural halogen chemistry in climate model projections of future tropospheric ozone.</jats:p>

Description

Funder: NSF


Funder: Office of Science of the US Department of Energy


Funder: PICT‐2016‐0714 (ANPCyT)


Funder: i‐COOP‐B20331 (CSIC + CONICET)

Keywords

ozone, halogens, climate, chemistry, emission

Journal Title

Journal of Geophysical Research: Atmospheres

Conference Name

Journal ISSN

2169-897X
2169-8996

Volume Title

126

Publisher

American Geophysical Union (AGU)
Sponsorship
EC, H2020, H2020 Priority Excellent Science, H2020 European Research Council (ERC) (ERC‐2016‐COG726349)