The hole in the ozone layer not only affects the health of human, land and marine ecosystems. It also affects environmental chemical processes at the South Pole. This has been demonstrated by an international research team coordinated by the National Research Council Institute of Polar Sciences (CNR-Isp) and Ca ‘Foscari University of Venice. They studied for the first time the effects of ozone depletion on iodine trapped in Antarctic ice. The results of the study, which also involved researchers from the Paul Scherrer Institute (PSI, Switzerland), the Institute of Interdisciplinary Sciences (Icb-Conicet, Argentina), the Rocasolano Institute of Physical Chemistry (Csic , Spain), the Korean Polar Research Institute (South Korea), the National Center for Atmospheric Research (United States) and the University of Rome 3, are published in the journal Nature Communication.
In Antarctica, where the ice contains valuable information about the past of our planet’s atmosphere, researchers have extracted an ice core about 12 meters long near the Concordia international research station. This was done with the aim of chemically analyzing the ice to discover the temporal evolution of iodine over a period of approximately 200 years (from 1800 to 2012). “For the first time, it was possible to observe and evaluate the effects of ultraviolet radiation on the concentration of this element in snow,” explains Andrea Spolaor, researcher at CNR-Isp and first author of this work. “Iodine plays a key role in polar atmospheric chemistry and in the planet’s radiation balance, so studying how it is exchanged between snow and the atmosphere is crucial to refine future climate and environmental projections. “
To assess and interpret trends in iodine concentrations in the ice core, the researchers used a multidisciplinary approach that included atmospheric and physicochemical models in addition to chemical analyzes. Dr Spolaor explains that “We found almost constant iodine levels from 1800 to 1974, then we found a clear and significant reduction from 1975 to 2012. Our research shows that the reduction in iodine concentration and its consequent emission into the atmosphere can be attributed to the reduction in the concentration of stratospheric ozone, resulting in increased UV radiation reaching the surface of Antarctica. “
“The implications of this discovery”, adds Carlo Barbante, director of CNR-Isp and professor at Ca ‘Foscari University, “are numerous and have the potential to open new avenues of research. We use the study of iodine in Antarctic ice cores to assess the presence of other stratospheric ozone depletion events that may have This could apply up to 1.5 million years ago, thanks to the imminent launch of the international project Beyond Epica, coordinated by the Cnr-Isp and in which the University Ca ‘Foscari “participates.
“More than 40 years after the identification of the thinning of the stratospheric ozone layer, these results are also relevant in light of current and future environmental and climate challenges,” concludes Francois Burgay, co-author of the research and postdoc at the Paul Scherrer Institute. “With this work, we show how humans have effects on the environment, and even when they are appropriately mitigated by the adoption of international protocols, which can continue for many decades with consequences largely unknown. For this reason, also in view of the next COP26 in Glasgow, we must act quickly to limit the long-term effects of the climate change already underway.The time factor is crucial.
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Antarctic ozone hole alters iodine geochemistry on the Antarctic plateau
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