September 16th is International Day for the Preservation of the Ozone Layer, celebrating the 1987 anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer. This protocol is the first environmental treaty to achieve universal ratification. The Montreal Protocol’s Kigali amendment, ratified on 1 January 2019, aims at mitigating the future impact on the Earth’s climate of hydrofluorocarbons or HFCs, which are substitutes for ozone depleting substances (ODSs) and powerful greenhouse gases. Universal ratification and compliance with this amendment would avoid about 0.5°C global temperature rise by the end of this century.

The theme of the International Day for the Preservation of the Ozone Layer on 16 September 2019 is: “32 Years and Healing”

Total atmospheric Ozone Depleting Substances (ODS) levels continue to decrease around the world according to the findings of the Scientific Assessment of Ozone Depletion: 2018 [WMO/UNEP, 2018]. This decrease is observed despite recent publications showing an unexpected increase of chlorofluorocarbon-11 (CFC-11 or CFCl3) emissions since 2012. CFC-11 is both the second most abundant ozone-depleting gas, banned under the Montreal protocol since 2010, and also a powerful greenhouse gas. This unexpected finding reinforces the continued need for surface network observations to track global emissions of ODSs and monitor compliance with the Montreal Protocol.

The Earth’s ozone layer continues to heal. Recent studies, as well as international reports on ozone trends indicate that ozone levels in the upper stratosphere are recovering in part, in response to the declines in ODSs. The SPARC report “Long-term Ozone Trends and Uncertainties in the Stratosphere (LOTUS)” found that upper stratospheric ozone has increased since 2000. Full stratospheric ozone recovery will take several decades due to the long lifetimes of ODSs in the atmosphere. Global ozone levels are expected to recover to 1980 levels in about 2050 based upon modeling results from the Chemistry Climate Model Initiative assessment.

The situation regarding Antarctic ozone hole is also improving. Total column ozone in early spring has increased over Antarctica since 2000. The ozone hole reappears every year and while its extent was fairly large in 2018, analyses show that it is less deep and extensive than in the period around the year 2000. This year’s unusually strong weather systems in the Southern Hemisphere stratosphere have  greatly weakened the ozone hole. These types of weather patterns are naturally occurring phenomena, but rare in the Southern Hemisphere – occurring only once, in 2002, in the last 4 decades. The 2019 ozone hole is therefore expected to be small compared to most other years.

Our ability to follow the future trends of ozone levels is crucially dependent on satellite, balloon, and ground-based ozone observing systems. The recently identified sources of CFC-11 emission increases demonstrate the necessity of continuous, quality-controlled observations for monitoring progress. The maintenance and continuation of ozone observations is vital for improving our understanding of interactions between climate change and ozone depletion, for ozone layer recovery studies, and for research into the geoengineering impacts on the ozone layer. At the centennial International Union of Geodesy and Geophysics (IUGG) meeting in Montreal, Canada, in July 2019, the International Ozone Commission led a scientific discussion on the efforts needed at international level to monitor both ozone recovery and decrease of ODS levels. Based on this discussion, IUGG and the International Association of Meteorology and Atmospheric Sciences adopted a resolution that urges national and international agencies to continue their support of measurements of ozone and related species, in order to ascertain the success of the Montreal Protocol and assess the evolution of atmospheric ozone over the 21st century.

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Noting

• The critical role of atmospheric ozone in the Earth’s climate and for screening dangerous solar ultraviolet radiation

Recalling that The Vienna Convention for the Protection of the Ozone Layer,

• obligates its Parties to take appropriate measures to protect human health and the environment against adverse effects resulting or likely to result from human activities which modify or are likely to modify the ozone layer,
• requires its Parties in accordance with the means at their disposal and their capabilities to co-operate by means of systematic observations, research and information exchange in order to better understand and assess the effects of human activities on the ozone layer and the effects on human health and the environment from modification of the ozone layer

Recalling that The Montreal Protocol on Substances that Deplete the Ozone Layer,

• under its Article 2a fully controls the production and consumption of trichlorofluoromethane (or chlorofluorocarbon-11, CFC-11, CFCl3)

Noting the recent WMO/UNEP “Scientific Assessment of Atmospheric Ozone: 2018” shows evidence of,

• a reduction of ozone depletion as levels of ozone depleting substances (ODSs) such as CFC-11 decline in our atmosphere,
• a slowing of the decline rate of atmospheric CFC-11 concentrations,
• an unexpected global increase of CFC-11 emissions

Urges,

• All countries to contribute through international cooperation and coordination to establish adequate and sustainable observing systems, ensuring high quality observations of ozone and ODSs on long time scales,
• Relevant international organizations such as the World Meteorological Organization’s Global Atmospheric Watch (WMO/GAW), the World Climate Research Program (WCRP), United Nations Environment, and international observation networks to work together to contribute to the previous objective,
• All countries to enhance their observations to better quantify regional emissions of ODSs through targeted field missions and long-term measurements,

Resolves

• To continue and promote national and international research efforts to insure an adequate observation system on ozone and ODSs to insure the protection of our environment from the dangerous effects of ultraviolet radiation.
• To take a scientific leadership role on developing and enhancing an adequate observing system for ODSs, ozone, and related substances.

November 2, 2018The ozone hole that forms over the Antarctic each September is primarily driven by two factors: the amount of ozone-destroying chlorine in the polar stratosphere and the availability of ice crystals in stratospheric clouds for the chlorine to bind to. This year, the super-cold stratospheric temperatures measured by NOAA and NASA meant conditions were ripe for the development of ice clouds – and a big ozone hole.

But the size of the 2018 ozone hole seen by NASA satellites was just a little larger than average, covering 8.83 million square miles (almost three times the size of contiguous United States). That’s because chlorine levels have been falling thanks to a 30-year-old global environmental treaty known as the Montreal Protocol.

« This year’s colder temperatures would have given us a much larger ozone hole if chlorine was still at levels we saw back in the year 2000,” said Paul A. Newman, chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Weather conditions allowed for near-complete elimination of ozone in a deep, 3.1-mile layer over the South Pole, NOAA scientist Bryan Johnson said. « Even with this year’s optimum conditions, ozone loss was less severe in the upper altitudes, » he said.

What is ozone and why does it matter?

Ozone, comprised of three oxygen atoms, occurs naturally in exceedingly small amounts. If compressed into its pure form, all of the ozone in a column of atmosphere extending from the ground to space would be about as thick as two pennies stacked one on top of the other.

While ozone’s presence is small, in the stratosphere, roughly 7 to 25 miles above Earth’s surface, ozone acts like sunscreen, shielding the planet from ultraviolet radiation that can cause skin cancer and cataracts, suppress immune systems and damage plants.

For more information see NOAA Research’s expanded report, NASA news release, NASA Ozone Watch, and NOAA’s Twenty Questions about the Ozone. 

Original source : https://www.noaa.gov/news/ozone-hole-couldve-been-big-one-year-but-it-wasn-t

The ozone hole that forms in the upper atmosphere over Antarctica each September was slightly above average size in 2018, NOAA and NASA scientists reported today.

Scientists from NASA and NOAA work together to track the ozone layer throughout the year and determine when the hole reaches its annual maximum extent. This year, the South Pole region of Antarctica was slightly colder than the previous few years, so the ozone hole grew larger.

Credits: NASA Goddard/ Katy Mersmann

This video can be downloaded for free at NASA’s Scientific Visualization Studio

Colder-than-average temperatures in the Antarctic stratosphere created ideal conditions for destroying ozone this year, but declining levels of ozone-depleting chemicals prevented the hole from as being as large as it would have been 20 years ago.

“Chlorine levels in the Antarctic stratosphere have fallen about 11 percent from the peak year in 2000,” said Paul A. Newman, chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. « This year’s colder temperatures would have given us a much larger ozone hole if chlorine was still at levels we saw back in the year 2000.”

According to NASA, the annual ozone hole reached an average area coverage of 8.83 million square miles (22.9 square kilometers) in 2018, almost three times the size of the contiguous United States. It ranks 13th largest out of 40 years of NASA satellite observations. Nations of the world began phasing out the use of ozone-depleting substances in 1987 under an international treaty known as the Montreal Protocol.

The 2018 ozone hole was strongly influenced by a stable and cold Antarctic vortex — the stratospheric low pressure system that flows clockwise in the atmosphere above Antarctica. These colder conditions — among the coldest since 1979 — helped support formation of more polar stratospheric clouds, whose cloud particles activate ozone-destroying forms of chlorine and bromine compounds.

In 2016 and 2017, warmer temperatures in September limited the formation of polar stratospheric clouds and slowed the ozone hole’s growth. In 2017, the ozone hole reached a size of 7.6 million square miles (19.7 square kilometers) before starting to recover. In 2016, the hole grew to 8 million square miles (20.7 square kilometers).

However, the current ozone hole area is still large compared to the 1980s, when the depletion of the ozone layer above Antarctica was first detected. Atmospheric levels of man-made ozone-depleting substances increased up to the year 2000. Since then, they have slowly declined but remain high enough to produce significant ozone loss.

NOAA scientists said colder temperatures in 2018 allowed for near-complete elimination of ozone in a deep, 3.1-mile (5-kilometer) layer over the South Pole. This layer is where the active chemical depletion of ozone occurs on polar stratospheric clouds. The amount of ozone over the South Pole reached a minimum of 104 Dobson units on Oct. 12 — making it the 12th lowest year out of 33 years of NOAA ozonesonde measurements at the South Pole, according to NOAA scientist Bryan Johnson.

« Even with this year’s optimum conditions, ozone loss was less severe in the upper altitude layers, which is what we would expect given the declining chlorine concentrations we’re seeing in the stratosphere, » Johnson said.

A Dobson unit is the standard measurement for the total amount of ozone in the atmosphere above a point on Earth’s surface, and it represents the number of ozone molecules required to create a layer of pure ozone 0.01 millimeters thick at a temperature of 32 degrees Fahrenheit (0 degrees Celsius) at an atmospheric pressure equivalent to Earth’s surface. A value of 104 Dobson units would be a layer that is 1.04 millimeters thick at the surface, less than the thickness of a dime.

Prior to the emergence of the Antarctic ozone hole in the 1970s, the average amount of ozone above the South Pole in September and October ranged from 250 to 350 Dobson units.

This time-lapse photo from Sept. 10, 2018, shows the flight path of an ozonesonde as it rises into the atmosphere over the South Pole from the Amundsen-Scott South Pole Station. Scientists release these balloon-borne sensors to measure the thickness of the protective ozone layer high up in the atmosphere.

Credits: Robert Schwarz/University of Minnesota

What is ozone and why does it matter?

Ozone comprises three oxygen atoms and is highly reactive with other chemicals. In the stratosphere, roughly 7 to 25 miles (about 11 to 40 kilometers) above Earth’s surface, a layer of ozone acts like sunscreen, shielding the planet from ultraviolet radiation that can cause skin cancer and cataracts, suppress immune systems and damage plants. Ozone can also be created by photochemical reactions between the Sun and pollution from vehicle emissions and other sources, forming harmful smog in the lower atmosphere.

NASA and NOAA use three complementary instrumental methods to monitor the growth and breakup of the ozone hole each year. Satellite instruments like the Ozone Monitoring Instrument on NASA’s Aura satellite and the Ozone Mapping Profiler Suite on the NASA-NOAA Suomi National Polar-orbiting Partnership satellite measure ozone across large areas from space. The Aura satellite’s Microwave Limb Sounder also measures certain chlorine-containing gases, providing estimates of total chlorine levels.

The total amount of ozone in the atmosphere is exceedingly small. All of the ozone in a column of the atmosphere extending from the ground to space would be 300 Dobson units, approximately the thickness of two pennies stacked one on top of the other.

NOAA scientists monitor the thickness of the ozone layer and its vertical distribution above the South Pole by regularly releasing weather balloons carrying ozone-measuring “sondes” up to 21 miles (~34 kilometers) in altitude, and with a ground-based instrument called a Dobson spectrophotometer.

To learn more about NOAA and NASA efforts to monitor ozone and ozone-depleting gases, visit:

https://ozonewatch.gsfc.nasa.gov/

https://www.esrl.noaa.gov/gmd/hats/

Twenty Questions About the Ozone – https://www.esrl.noaa.gov/csd/assessments/ozone/2014/twentyquestions/

Original source : https://www.nasa.gov/feature/goddard/2018/ozone-hole-modest-despite-optimum-conditions-for-ozone-depletion

2019 : Session M21 – Celebrating the montreal protocol in montreal : assessing ozone layer recovery in an evolving climate

at 27th International Union of Geodesy and Geophysics (IUGG) General Assembly, 8 – 18 July 2019, Montreal, Canada

http://iugg2019montreal.com/abstract-submission.html

Conveners: Sophie Godin-Beekmann (France), Paul Newman (USA), Irina Petropavloskikh (USA)

The « Celebrating the Montreal Protocol in Montreal: assessing Ozone Layer Recovery in an Evolving Climate” Symposium solicits presentations on all aspects of ozone science, ozone depletion, and related research. More particularly, the symposium calls for oral talks and poster presentations that highlight contributions to the themes of WMO/UNEP report, “The Scientific Assessment of Ozone Depletion: 2018.” This assessment report included chapters on:

• 1) Ozone-Depleting Substances;
• 2) Hydrofluorocarbons;
• 3) Global stratospheric ozone: Past, present & future;
• 4) Polar stratospheric ozone: Past, present & future;
• 5) Stratospheric ozone changes and climate; and
• 6) Scenarios and Information for Policymakers.

September 16th is International Day for the Preservation of the Ozone Layer, commemorating the 1987 anniversary of the signing of the Montreal Protocol on Substances that Deplete the Ozone Layer. Hailed as an example of exceptional international cooperation for the protection of the ozone layer, the Montreal Protocol became the first international treaty to achieve universal ratification. The Montreal Protocol expanded in October 2016 with the addition of the Kigali amendment. This amendment mitigates the impact on the Earth’s climate by substitutes of ozone depleting substances that are powerful greenhouse gases.

The theme of the International Day for the Preservation of the Ozone Layer on 16 September 2018 is: “Keep Cool and Carry on”

The ozone layer is on the mend. A number of recent studies, as well as international reports on ozone trends indicate that ozone levels in the Antarctic ozone hole and in the upper stratosphere of the northern hemisphere are increasing. In the Antarctic, several studies have reported total ozone increases since 2000 in early spring. While the ozone hole has reappeared in 2018, findings now show that on average, ozone holes are less deep and less extensive than since the period around the year 2000. As mandated by the Montreal Protocol, a new Ozone Assessment will be released in December 2018. It assesses these signs of ozone layer recovery. Since the last WMO/UNEP Ozone assessment that was published in 2014, ground-based and satellite data records have been extended, and global datasets now cover several decades for assessing ozone recovery. The new SPARC report “Long-term Ozone Trends and Uncertainties in the Stratosphere (LOTUS)” will be released in Fall of 2018 and documents ozone increases since 2000 in the upper stratosphere. However, due to the long lifetimes of ODSs in the atmosphere, only certain regions are showing ozone increases, and full stratospheric ozone recovery will take several decades. Global ozone levels are expected to recover to 1980 levels in about 2050. Stratospheric ozone recovery will also be impacted by climate change. The recently published modeling results of the Chemistry Climate Model Initiative assessment provided updates for the dates of expected ozone recovery.

Stratospheric ozone increases are largely ascribed to decreasing atmospheric ODS levels thanks to the Montreal Protocol controls. Surface ground network observations are crucial to calculate the annual global emissions of atmospheric ODSs. Since the implementation of the Montreal Protocol controls, these ODS emissions have decreased as industries have transitioned to more ozone-safe compounds. However, Montzka et al. [2018]* reported that emissions of chlorofluorocarbon-11 (CFC-11 or CFCl3), the second most abundant ozone-depleting gas, had unexpectedly increased in the 2014-2016 period from the 2002-2012 average level. CFC-11 is both an ODS (banned under the Montreal protocol since 2010), but it is also a powerful greenhouse gas. Some of this CFC-11 emission increase has been traced to east Asia, but regional emissions, production sources, and usages have not been quantified. Large ODS emission increases pose a new threat to the ozone layer. Our ability to follow future ozone levels is crucially dependent on satellite, balloon, and ground-based ozone observing systems. The recent observations of the CFC-11 emission increases prove the necessity of high-quality observations for monitoring our atmosphere. The maintenance and continuation of ozone observations is necessary for improving our scientific understanding of interactions between climate change and ozone depletion, for making sure that the ozone layer indeed recovers as ozone depleting substances decline under the Montreal Protocol, and for observing the ozone layer under changing climate conditions. The International Ozone Commission (IO3C) of IAMAS-IUGG urges national and international agencies to continue their support of measurements of ozone and related species, in order to ascertain the success of the Montreal Protocol and to understand and observe the evolution of atmospheric ozone over the 21st century.

See the whole statement

www.montreal30.io3c.org

Symposium replay

Photo gallery

19 – 20 September 2017

Fondation Del  Duca, Paris, France

From the safeguard of the ozone layer to the protection of the Earth climate

Hailed as an example of exceptional international cooperation for the protection of the ozone layer, the Montreal Protocol became in 2010 the first international treaty to achieve universal ratification. In October 2016, the Kigali amendment was added to the Protocol for controlling the growth of the substitutes of ozone depleting substances, some of which are powerful greenhouse gases and thereby mitigating their impact on the Earth’s climate.

Symposium themes:

• The history of atmospheric ozone and the discovery of the ozone hole
• Ozone layer science: historical and present perspectives
• The impact of ozone depletion on climate
• Environmental effects of the ozone depletion
• The industry role in the Montreal Protocol and the search for substitutes
• The impact of hydrofluorocarbons on climate and the Kigali amendment
• Geoengineering and the future ozone layer
• Ozone and climate controversies

Organization

Observatoire de Versailles Saint-Quentin en Yvelines, Institut Pierre-Simon Laplace, Académie des Sciences, International Ozone Commission, World Meteorological Organization, the United Nations Environmental Programme, World Climate Research Programme (Stratosphere – Troposphere processes and their role in climate)

More information

www.montreal30.io3c.org

The International Ozone Commission, on the 31st anniversary of the Vienna Convention for the protection of the Ozone Layer, reports that despite signs of healing, the ozone layer continues to be affected by large ozone depletion in Antarctica. Please see the Press Release.

The Quadrennial Ozone symposium held in Edinburgh, Scotland. More than 300 scientists from all over the world gathered to discuss ozone research and the current status of atmospheric ozone, including preliminary results from this year’s ozone hole. Please see the conference website for further information.