NASA Goddard Space This ‘good ozone’ typically absorbs 97-99 percent of incoming UV-B radiation. In the chart we see various projections of historic and future concentrations of effective chlorine substances (i.e. This allows us to track atmospheric concentrations over time. Using the ‘play’ button on the map allows you to view changes across the world since 1989. Melanoma mortality and exposure to ultraviolet radiation: an empirical relationship. A., & Tourpali, K. (2013). Although depletion has occurred over both the Antarctic and Artic poles, Antarctica has experienced the most severe development of the ‘ozone hole’. Why is ozone depletion more severe at high latitudes? ODS can have a significant lifetime in the atmosphere, for some between 50 and 100 years on average. In 2009, the Vienna Convention became the first of any Convention to achieve universal ratification. Scientists found out that chlorofluorocarbons (CFCs)—long-lived chemicals that had been used in refrigerators and aerosol sprays since the 1930s—had a dark side. The 2019 Ozone Layer Hole Is Now the Smallest on Record; The 2019 Ozone Layer Hole Is Now the Smallest on Record . Please consult our full legal disclaimer. The daily progression through the 2020 ozone hole season of the various ozone statistics, comparing 2020 to the climatology of all other years. (2015). View the latest status of the ozone layer over the Antarctic, with a focus on the ozone hole. However, a 2018 study published in Nature reported “an unexpected and persistent increase in global emissions of ozone-depleting CFC-11”.7. Even once emissions of ODS cease; why does the concentration of these substances not return to zero? However, full recovery of stratospheric ozone concentrations to historical levels is projected to take many more decades. "The 2020 ozone hole resembles the one from 2018, which also was a quite large hole, and is definitely in the upper part of the pack of the last fifteen years or so. In the entry above we present data on production/consumption, emissions, and stratospheric concentrations of ozone-depleting substances. Montzka et al. Since 2012, however, the annual rate of decline in concentrations has fallen (almost halved from -0.8 percent to -0.4 percent per year). There are a significant number of ODS, including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), methyl chloride and bromide, and halons. Immunology and Cell Biology, 79(6), 547. Note that, as with other measures throughout this entry, each substance has been weighted by its potential to destroy ozone. The ozone hole over the Antarctic has reached its 2020 peak and is one of the largest holes of recent years. As a result, even if emissions were halted, depleting substances (which were previously emitted) would continue to persist in the stratosphere. Find out what caused the ozone hole, and how the 1989 Montreal Protocol sought to put an end to ozone depletion. This data measures the indexed consumption of ODS to the 1986 (i.e. The Montreal Protocol (and later amendments) was adopted in 1987 — since then all countries have signed on to the agreement, allowing for the dramatic decline in global ozone-depleting emissions. [The Kyoto Protocol was the international treaty for the United Nations Framework for Climate Change adopted in 1997, specifically designed to reduce greenhouse gas emissions]. How critical was the Montreal Protocol in reducing ODS consumption and stratospheric concentrations? The primary role of the Vienna Convention, Montreal Protocol and its subsequent revisions was to protect depletion of the stratospheric ozone layer. Ozone-depleting substances (ODS) are typically measured in ‘ozone depletion potential’ (ODP) tonnes. As the images show, the word hole isn’t literal; no place is empty of ozone. However this could be minimised (to the span of a few years) if emissions are now rapidly reduced (and return close to zero, as reported within the Ozone Secretariat). In 2019, abnormal weather patterns in the upper atmosphere over Antarctica dramatically limited ozone depletion, leading to the smallest hole since 1982. The measurements were made from 1979–2004 by NASA’s Total Ozone Mapping Spectrometer (TOMS) instruments; from 2005–2011 by the Royal Netherlands Meteorological Institute’s Ozone Monitoring Instrument (OMI) (which flies on NASA’s Aura satellite); and from 2012-2019 by the Ozone Mapping Profiler Suite (OMPS) on the NASA/NOAA Suomi NPP satellite. Its purpose was to phase-out (reduce and eventually eliminate) the use of man-made ozone-depleting substances for protection of the ozone layer. Emissions of ODS result from the production/consumption of new materials or products, but they can also occur in the absence of new production. However, the Copenhagen (1992) and its subsequent revisions greatly increased controls and ambition in global commitments, leading to a peak in stratospheric concentrations in the early 2000s and projected declines in the decades to follow. Available at: https://www.wmo.int/pages/prog/arep/gaw/ozone_2014/documents/2014%20Twenty%20Questions_Final.pdf. United Nations Environment Programme (UNEP). Since 1979 we see a distinct increase in the Antarctic ozone hole area, reaching a maximum of 30 million km2 in the early 2000s. Since its first draft in 1987, the Montreal Protocol has undergone numerous amendments of increasing ambition and reduction targets. The data presented is measured relative to concentrations in 1960 (where 1960 is equal to 0). A reduction or slowdown in emissions relative to a ‘no protocol’ scenario would have been achieved but this would be insufficient to lead to an absolute reduction. Models suggest that the concentration of chlorine and other ozone-depleting substances in the stratosphere will not return to pre-1980 levels until the middle decades of the 21st century. The global shift away from ozone-depleting substances has also had co-benefits on the reduction of greenhouse gas emissions. Click any map image to bring up a new page with a high-resolution image. In the upper stratosphere (beyond the protection of the ozone layer), ultraviolet light caused CFCs to break apart, releasing chlorine, a very reactive atom that repeatedly catalyzes ozone destruction. In the chart we see the maximum and mean ozone hole area over Antarctica, measured in square kilometres (km2). One of the first studies to attempt to quantify excess skin cancer cases, despite being published in the 1990s correlates well with results from recent studies.15. (2013)  quantified the total number of cases of skin cancer avoided as a result of the Montreal Protocol and its subsequent amendments.14. By 2010, emissions had returned to 1960 levels. Preserving Montreal Protocol climate benefits by limiting HFCs. Blue trends map the estimated impact had the Montreal Protocol not been adopted: it is based on the assumption of a 2 to 3 percent (dashed and solid line) increase in annual production of halogen substances. The reduction in ODS, in particular CFCs has therefore had a significant impact on greenhouse gas reduction in recent years. Over the last few decades we have seen a dramatic decline in emissions of ozone-depleting substances. Abnormal weather patterns in the upper atmosphere over Antarctica dramatically limited ozone depletion in September and October, resulting in the smallest ozone hole observed since 1982, NASA and NOAA scientists reported today. Available at: http://science.sciencemag.org/content/335/6071/922. The ozone layer helps to protect life from harmful ultraviolet radiation. However, it’s also interesting to note the relative decline and change in the quantity of individual substances. Ozone depletion (and the subsequent increase in UV-B irradiation, as discussed above), can increase negative health impacts such as skin cancer, and other implications such as sunburn and skin ageing.12,13. In the chart we see the annual change (in percent) of measured concentrations of CFC-11 (shown as the solid line). By checking the ‘relative’ box you can also view percentage share of a given substance to total ODS consumption. Available at: http://www.pnas.org/content/pnas/104/12/4814.full.pdf. Measurewments Show Reduction in Ozone-Eating Chemical. Its structure means that it’s much less stable than oxygen (O2), and is therefore much more reactive; this means it can be more easily formed and broken down through interaction with other compounds. Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2009JD012219. In the chart we see average stratospheric ozone concentrations in the Southern Hemisphere (where ozone depletion has been most severe) from 1979 to 2017. Through the first decade this trend largely stabilized and we now see initial signs of recovery. Why is this the case? Hegglin, M. I. et al. The maximum depth of the hole that year was 194 Dobson Units (DU)—not far below the previous historical low. This rapidly increased in the years to follow, reaching 174 parties by 2000. For several decades since the 1990s, concentrations have continued to approximate around (or below) 100 DU. This replacement was therefore been an important reduction strategy (particularly where the complete phase-out of ozone depleting substances was not readily available). It’s important to note the distinction between these measures, and why they are not equivalent. Here you see that despite recent emissions, total concentrations continue to fall but at a notably slower rate than expected. As shown in following section, subsequent amendments were been critical in the Protocol’s success in reducing ODS consumption. Throughout the 1990s and first half of the 2000s, chlorofluorocarbons (CFCs) dominated global consumption (accounting for 60 percent, reducing to 50 percent). Ozone (O3) is a gas which is present naturally within Earth's atmosphere. In the chart we see the breakdown of consumption by substance. Available at: http://ozone.unep.org/en/handbook-vienna-convention-protection-ozone-layer/2205. Available at: https://www.nature.com/articles/366023a0.pdf. Using combined ozone, UV and dose-response models, numerous studies have attempted to quantify the potential increase in skin cancer cases as a result of ozone depletion. Chlorofluorocarbons (CFCs) have almost been completely phased out, declining from over 800,000 tonnes in 1989 to 156 tonnes in 2014. Scientists have already seen the first definitive proof of ozone recovery, observing a 20 percent decrease in ozone depletion during the winter months from 2005 to 2016. Montzka et al. Ozone-depleting substances (ODS) are halogen gases containing chlorine and/or bromine which have the potential to break down ozone in the stratosphere. The ozone layer is found many miles … In the figure we show the average percentage change in UV irradiation reach the surface in 2008 relative to levels in 1979.11. In 2019, abnormal weather patterns in the upper atmosphere over Antarctica dramatically limited ozone depletion, leading to the smallest hole since 1982. It is formed of three oxygen atoms (giving it the chemical formula, O3). Journal of Geophysical Research: Atmospheres, 115(D4). Clydesdale, G. J., Dandie, G. W., & Muller, H. K. (2001). Concentrations of ozone-depleting substances in the atmosphere are determined by the stock of substances, in addition to the balance of inputs and outputs over time. Shown are the changes across wavelengths from 305 to 325 nanometres, which is the region where DNA damage from UV irradiation has its largest health impacts. Production/consumption of ozone-depleting substances refers to the primary production of new materials or products containing any of the halogen gases noted as ODS. In the layer of the atmosphere closest to Earth (the troposphere), CFCs circulated for decades without degrading or reacting with other chemicals.

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