Long-term future development of LS tropical ozone. a, indices of 20-year mean change of ozone concentration relative to the 1998–2018 average in UppLim8.5, LowLim8.5, UppLim6.0, and LowLim6.0 simulations. The indices represent four-member group mean values ± 95% confidence interval. The dashed horizontal line indicates the threshold for severe ozone depletion for the recent past. ∆6.0 and ∆8.5 for the gap obtained by the year 2100 by reducing anthropogenic VSLS emissions, respectively, under the RCP6.0 and RCP8.5 scenarios. BAndcthe latitude and altitude profiles of pressure levels (hPa) of the four-member averaged stratospheric ozone change across 2080–2099 are represented, respectively, by LowLim6.0 (B) and UpLim8.5 (c) simulation. credit: The nature of climate change (2023). DOI: 10.1038/s41558-023-01671-y
An international team of climate scientists has used climate models to show that certain short-lived substances are partially responsible for the depletion of the ozone layer over the tropics. In their paper published in the journal The nature of climate change, the group describes how they used a variety of climate models to simulate the effect of short-lived substances (VSLS) on the lower portions of the ozone layer above the tropics and what they learned by doing so. Seok-Woo Son, along with Seoul National University, published a News & Views article in the same issue of the magazine outlining the work the team has done on this new effort.
In the 1980s, it became clear that the substances used by humans harm the ozone layer, a layer of the Earth’s stratosphere with a high concentration of ozone, which is very important for life on Earth because it absorbs ultraviolet radiation. Concerned about the harm, world leaders created the Montreal Protocol in 1987. It called for a moratorium on CFCs and some other aerosols. The protocol worked as hoped, and the ozone layer began to recover.
But recently, it was found that there is still a problem in the tropics, and depletion is still occurring. Some have suggested that this is due to the rapid flow of warm air, which blows winds from the tropics toward the poles, leaving a thin ozone layer over the tropics. In this new effort, the researchers suggest that such an explanation is only partially true. They think there are some other gases that are also part of the problem.
Suspecting that halogenated VSLS may play a role in ozone depletion over the tropics, the research team ran a set of simulations using what they describe as a variety of complex climate models to show what happens when VSLS enters the atmosphere. They found that these substances live long enough to make their way to the lower parts of the stratosphere where they damage the lower parts of the ozone layer. The research team noted that the VSLS was able to do this, due to strong upwelling winds over the tropics.
Their simulations showed that the VSLS is likely responsible for up to 25% of the damage to the lower part of the ozone layer above the tropics over the past two decades. They conclude their study by proposing that VSLS be added to the list of prohibited substances.
more information:
Julián Villamayor et al, Very short-lived halogens amplify ozone depletion trends in the lower tropical stratosphere, The nature of climate change (2023). DOI: 10.1038/s41558-023-01671-y
Seok-Woo Son, Stratospheric Ozone Loss by Extremely Short-lived Materials, The nature of climate change (2023). DOI: 10.1038/s41558-023-01687-4
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the quote: Researchers suggest short-lived halogens partially responsible for ozone depletion over the tropics (2023, May 29) Retrieved May 29, 2023 from https://phys.org/news/2023-05-short-lived-halogens-partially – blame ozone.html
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