Ozone may be heating the planet more than we realizehttps://phys.org/news/2022-03-ozone-planet.htmlA new study has revealed that changes to ozone levels in the upper and lower atmosphere were responsible for almost a third of the warming seen in ocean waters bordering Antarctica in the second half of the 20th century.
The deep and rapid warming in the Southern Ocean affects its role as one of the main regions for soaking up excess heat as the planet warms.
The majority of this warming was the result of ozone increases in the lower atmosphere. Ozone—one of the main components of smog—is already hazardous as a pollutant, but the research shows it may also play a significant role in driving climate change in the coming years.
Dr. Michaela Hegglin, an Associate Professor in atmospheric chemistry and one of the study's authors, said: "Ozone close to Earth's surface is harmful to people and the environment, but this study reveals it also has a big impact on the ocean's ability to absorb excess heat from the atmosphere.
"These findings are an eye-opener and hammer home the importance of regulating air pollution to prevent increased ozone levels and global temperatures rising further still."
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They revealed that the increased ozone in the lower atmosphere caused 60% of the overall ozone-induced warming seen in the Southern Ocean over the period studied—far more than previously thought. This was surprising because tropospheric ozone increases are mainly thought of as a climate forcing in the Northern hemisphere since that is where the main pollution occurs.
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"We have known for a while that ozone depletion high in the atmosphere has affected surface climate in the Southern Hemisphere. Our research has shown that ozone increases in the lower atmosphere due to air pollution, which occurs primarily in the Northern Hemisphere and 'leaks' into the Southern Hemisphere, is a serious problem as well.
Changes in ozone concentrations in the atmosphere affect westerly winds in the Southern Hemisphere as well as causing contrasting levels of salt and temperature close to the surface in the Southern Ocean. Both affect ocean currents in distinct ways, thereby affecting ocean heat uptake.