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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Efficiency of short-lived halogens at influencing climate through depletion of stratospheric ozone
AU - Hossaini, R.
AU - Chipperfield, M. P.
AU - Montzka, S. A.
AU - Rap, A.
AU - Dhomse, S.
AU - Feng, W.
PY - 2015/3
Y1 - 2015/3
N2 - 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.
AB - 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.
KW - BROMINE
KW - TROPOSPHERE
KW - EMISSIONS
KW - IODINE
KW - SUBSTANCES
KW - TRENDS
KW - IMPACT
KW - MODEL
U2 - 10.1038/NGEO2363
DO - 10.1038/NGEO2363
M3 - Journal article
VL - 8
SP - 186
EP - 190
JO - Nature Geoscience
JF - Nature Geoscience
SN - 1752-0894
IS - 3
ER -