While climate change continues to affect the mainlands, the cold frigid regions of Antarctica and the Arctic are no different to it. While the role of chlorofluorocarbons (CFC) has been widely established, an international team of researchers has found a new element that is damaging the Ozone over the Arctic.
The new culprit is Iodine.
Over a hundred researchers from 20 countries, including the Indian Institute of Tropical Meteorology (IITM), Pune, in collaboration with Extreme Environments Research Laboratory, Switzerland, The Cyprus Institute, and NOAA Physical Sciences Laboratory, joined hands to analyse the changes in the Arctic. The researchers found that the chemical reactions between Iodine and Ozone were the second highest contributor to the loss of surface Ozone.
Their findings have been published in the journal Nature Geosciences after the observations were conducted by the researchers during the ship-based Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The new findings are set to change the decades-old paradigm on the drivers of Arctic photochemical Ozone loss.
WHAT IS OZONE?
The Ozone layer is found in the troposphere, the lower 10 kilometers of the atmosphere, and in the stratosphere that extends 10-50 km above the ground. According to the World Meteorological Department, Ozone is a form of oxygen with molecules carrying three atoms instead of two and acts as a shield protecting us against harmful ultraviolet radiation from the Sun.
The Ozone has been under attack from chlorine (chlorofluorocarbon, CFC) and bromine (halon) compounds that were largely being used in refrigerants, pesticides, solvents, and fire extinguishers. This led to the development of a major hole in the Ozone layer, which has since then closed.
"The main driver for this is the anthropogenic emissions of chlorofluorocarbons (CFCs). However, similar, but shorter-lived, ozone depletion events are seen close to the surface of the Earth," IITM said in a statement, adding that during these depletion events, ozone concentrations drop to nearly zero.
HOW IS IODINE DAMAGING OZONE?
The team of researchers conducted observations from March to October 2020 on a ship in the high Arctic region and found that Iodine enhances springtime tropospheric Ozone depletion. They developed a chemical model to show that chemical reactions between Iodine and Ozone are the second highest contributor to the loss of surface Ozone.
The study further suggests that the atmospheric increase in Iodine loading due to enhanced anthropogenic Ozone-induced ocean Iodine emissions, as well as the thinning and shrinking of Arctic sea ice expected in the near future, will probably lead to increases in Iodine emissions.
"These results indicate that iodine chemistry could play an increasingly important role in the future and must be considered for accurate quantification of the ozone budget in the Arctic," IITM said in a release.
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