Efficiency of short-lived halogens at influencing climate through depletion of stratospheric ozone

Hossaini, R. and Chipperfield, M. P. and Montzka, S. A. and Rap, A. and Dhomse, S. and Feng, W. (2015) Efficiency of short-lived halogens at influencing climate through depletion of stratospheric ozone. Nature Geoscience, 8 (3). pp. 186-190. ISSN 1752-0894

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Abstract

Halogens released from long-lived anthropogenic substances, such as chlorofluorocarbons, are the principal cause of recent depletion of stratospheric ozone, a greenhouse gas(1-3). Recent observations show that very short-lived substances, with lifetimes generally under six months, are also an important source of stratospheric halogens(4,5). Short-lived bromine substances are produced naturally by seaweed and phytoplankton, whereas short-lived chlorine substances are primarily anthropogenic. Here we used a chemical transport model to quantify the depletion of ozone in the lower stratosphere from short-lived halogen substances, and a radiative transfer model to quantify the radiative effects of that ozone depletion. According to our simulations, ozone loss from short-lived substances had a radiative effect nearly half that from long-lived halocarbons in 2011 and, since pre-industrial times, has contributed a total of about -0.02 W m(-2) to global radiative forcing. We find natural short-lived bromine substances exert a 3.6 times larger ozone radiative effect than long-lived halocarbons, normalized by halogen content, and show atmospheric levels of dichloromethane, a short-lived chlorine substance not controlled by the Montreal Protocol, are rapidly increasing. We conclude that potential further significant increases in the atmospheric abundance of short-lived halogen substances, through changing natural processes(6-8) or continued anthropogenic emissions(9), could be important for future climate.

Item Type:
Journal Article
Journal or Publication Title:
Nature Geoscience
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900
Subjects:
ID Code:
82370
Deposited By:
Deposited On:
24 Oct 2016 10:04
Refereed?:
Yes
Published?:
Published
Last Modified:
07 Apr 2020 04:00