2023-06-20. Protecting the Ozone Layer Is Delaying Arctic Melting. [https://eos.org/articles/protecting-the-ozone-layer-is-delaying-arctic-melting] By Sofia Moutinho, Eos/AGU. Excerpt: Efforts to protect the ozone layer have unintentionally benefited Earth’s climate. The Montreal Protocol in particular has not only reduced the “ozone hole” but also slowed global warming. The treaty, a groundbreaking 1989 international commitment to phase out production of ozone-depleting substances, has also delayed the occurrence of the first ice-free summer in the Arctic by up to 15 years, according to a new analysis published in the Proceedings of the National Academy of Sciences of the United States of America….
2023-04-12. Wildfire Smoke Destroys Ozone. [https://eos.org/articles/wildfire-smoke-destroys-ozone] By Elise Cutts, Eos/AGU. Excerpt: n the middle of the 20th century, humanity unleashed chlorofluorocarbons (CFCs) into the atmosphere. By the 1980s, CFCs had gnawed away at the planet’s ozone shield, endangering safety and health on Earth. Worldwide restrictions and bans have begun to heal the damage, but new results have suggested that increasingly severe wildfires could be stalling progress. Liquid droplets containing wildfire smoke act like tiny reaction chambers for chlorine in the stratosphere, producing reactive forms of the element that degrade ozone over the midlatitudes, researchers reported in Nature. This chemical mechanism had “never been seen before,” said study coauthor and atmospheric scientist Kane Stone of the Massachusetts Institute of Technology. “This is a completely new chemistry that we’re looking at.” Large wildfires are expected to happen more often as the planet warms, so the new finding has raised concerns that intensifying fires could stall the recovery of the stratospheric ozone layer, which protects Earth’s surface and its inhabitants from harmful ultraviolet (UV) radiation….
2023-01-09. Earth’s ozone layer on course to be healed within decades, UN report finds. [https://www.theguardian.com/environment/2023/jan/09/ozone-layer-healed-within-decades-un-report] By Oliver Milman, The Guardian. Excerpt: The hole in the Earth’s ozone layer, once the most feared environmental peril facing humanity, is set to be completely healed over most of the world within two decades following decisive action by governments to phase out ozone-depleting substances, a new UN assessment has found. The loss of the ozone layer, which risked exposing people to harmful ultraviolet rays from the sun, is on track to be completely recovered by 2040 across the world, aside from the polar regions, according to the report. The poles will take a little longer – the ozone layer will fully bounce back by 2045 over the Arctic and by 2066 over the Antarctic.… See also New York Times article, Restoration of the Ozone Layer Is Back on Track, Scientists Say.
2022-05-02. Ozone-destroying chemical is on the rise despite crackdown. By Warren Cornwall, Science Magazine. Excerpt: Levels of an ozone-destroying chemical are mysteriously rising, despite international efforts to crack down on the problem. The uptick in the airborne chemical HCFC-141b comes even though reported production has declined steadily since 2012, leaving scientists stumped about the source. …The chemical, used chiefly to make foam insulation for appliances such as refrigerators, is part of a family of fluorocarbon molecules blamed for eating away at a layer of stratospheric ozone, roughly 20 kilometers above the ground, that filters out harmful ultraviolet radiation from the Sun. The world began to wean itself off these chemicals under the 1987 Montreal Protocol, widely considered the most successful international environmental treaty. Overall, ozone-damaging chemicals have declined steadily since the early 2000s, and the ozone “holes” above the poles have begun to heal. In 2018, however, researchers reported that levels of the banned chemical CFC-11 had been rising since 2012. An international panel concluded that surge was likely due to illicit production, much of it in eastern China, perhaps because HCFC-141b, then used as a substitute for CFC-11 because it is less destructive to ozone, was in scarce supply. Releases of CFC-11 started to fall once again in 2019. …But scientists say atmospheric levels of HCFC-141b are actually rising. … [https://www.science.org/content/article/ozone-destroying-chemical-rise-despite-crackdown]
2022-04-04. Australian Wildfires Linked to Ozone Layer Depletion. By Krystal Vasquez, Eos/AGU. Excerpt: The Australian “Black Summer” bushfires produced nearly 1 million tons of smoke in 2019 and 2020, wreaking havoc on local air quality. But new research has shown that this is far from the only impact that the smoke had on the atmosphere. According to the study, published in the Proceedings of the National Academy of Sciences of the United States of America, thunderstorms generated by the intense wildfires thrust smoke particles well into the stratosphere, where they contributed to a 1% loss of the ozone layer. That’s the amount that should have been recovered over the past decade due to the adoption of the Montreal Protocol, said Susan Solomon, a professor of environmental studies and chemistry at the Massachusetts Institute of Technology and lead author on the paper. “This fire offset that in one blow.”.… [https://eos.org/articles/australian-wildfires-linked-to-ozone-layer-depletion]
2021-11-18. High-flying wildfire smoke may threaten ozone layer. By Paul Voosen, Science Magazine. Excerpt: Record Arctic ozone loss linked to Siberian wildfires… [https://www.science.org/content/article/high-flying-wildfire-smoke-may-threaten-ozone-layer]
2021-09-02. How the “Best Accidental Climate Treaty” Stopped Runaway Climate Change. Source: By Jenessa Duncombe, Eos/AGU. Excerpt: The Montreal Protocol halted the destruction of the ozone layer. In the process, it saved one of Earth’s most important carbon sinks. …The international treaty that phased out the production of ozone-depleting chemicals has prevented between 0.65°C and 1°C of global warming, according to research. The study also showed that carbon stored in vegetation through photosynthesis would have dropped by 30% without the treaty, which came into force in 1989. Researchers from the United Kingdom, New Zealand, and the United States wrote in Nature that the Montreal Protocol was essential in protecting carbon stored in plants. Studies in the polar regions have shown that high-energy ultraviolet rays (UVB) reduce plant biomass and damage DNA. Forests and soil currently absorb 30% of human carbon dioxide emissions. …In the simulation, the UVB radiation is so intense that plants in the midlatitudes stop taking up a net increase in carbon. Plants in the tropics fare better, but humid forests would have 60% less ozone overhead than before, a state much worse than was ever observed in the Antarctic ozone hole.… [https://eos.org/articles/how-the-best-accidental-climate-treaty-stopped-runaway-climate-change]
2021-02-10. China’s Emissions of Ozone-Harming Gas Are Declining, Studies Find. By Chris Buckley and Henry Fountain, The New York Times. Excerpt: Emissions from China of a banned gas that harms Earth’s ozone layer have sharply declined after increasing for several years, …a sign that the Beijing government had made good on vows to crack down on illegal production of the industrial chemical. …CFC-11 was outlawed a decade ago under the Montreal Protocol, the treaty established in the 1980s, when research revealed its effects on atmospheric ozone, along with the effects of similar widely used chemicals. The revelation in a 2018 study of rogue emissions from China that began five years before was a shock to scientists, policymakers, environmentalists and others who monitor the protocol, which is largely regarded as the most effective environmental treaty in history…. [https://www.nytimes.com/2021/02/10/climate/ozone-layer-china-cfcs.html]
2020-11-20. An Extraordinary Winter in the Polar North. By Kate Wheeling, Eos/AGU. Excerpt: The winter of 2019–2020 in the Northern Hemisphere was one of extremes. The massive region of cold polar air encircled by stratospheric winds, known as the stratospheric polar vortex, was particularly strong, keeping the frigid air whirling above the polar region and leading to a very mild winter in many regions farther south. The strong polar vortex coincided with a record-breaking positive Arctic Oscillation circulation pattern and record low ozone levels in the Arctic that lasted into spring. In a review, published as part of an AGU special collection, Lawrence et al.outline the unique conditions that allowed this “truly extraordinary” winter season to arise…. [https://eos.org/research-spotlights/an-extraordinary-winter-in-the-polar-north]
2019-11-04. Banned Ozone-Harming Gas, Once on the Rise, Declines Again. By Henry Fountain, The New York Times. [https://www.nytimes.com/2019/11/04/climate/china-cfcs.html] Excerpt: Emissions of a banned ozone-destroying gas that had risen unexpectedly since 2012 appear to have declined in the last two years, according to preliminary data reported by scientists on Monday….
2019-05-22. Rogue ozone-destroying emissions traced to northeastern China. By Dennis Normile, Science Magazine. https://www.sciencemag.org/news/2019/05/rogue-ozone-destroying-emissions-traced-northeastern-china] Excerpt: An international team of researchers has traced the rogue use of a banned, ozone-degrading chemical to a region centered on two provinces in northeastern China. Trichlorofluoromethane (CFC-11), once a common refrigerant also used to produce building insulation, was to be phased out by 2010 under the 1987 Montreal Protocol because of its contribution to a then–rapidly growing hole in Earth’s ozone layer. As use declined ahead of the ban, atmospheric concentrations of CFC-11 started to drop. …But in 2012, levels started to increase in the Northern Hemisphere, with evidence pointing to sources in China. Now, Matthew Rigby of the University of Bristol in the United Kingdom and colleagues have used atmospheric observations and modeling to narrow down both the source and the magnitude of emissions, showing they are coming from Shandong and Hebei provinces and represent new production and use of CFC-11. In addition, amounts have increased since the chemical was banned, the team reports today in Nature. …“The Chinese have been doing the best they can” to identify and shut down the rogue operations, Rae says. “But regulators have real trouble keeping tabs on what is going on” throughout the country. …“We hope that the information that this new study provided helps the Chinese government take steps to address the issue,” says Sunyoung Park, a study co-author….
2018-11-05. Encouraging report from UN on ozone restoration.By Seth Borenstein, San Francisco Chronicle. [https://m.sfgate.com/nation/article/Encouraging-report-from-UN-on-ozone-restoration-13364438.php] Excerpt: …Earth’s protective ozone layer is finally healing from damage caused by aerosol sprays and coolants, according to a new report from the United Nations. As a result, the upper ozone layer above the Northern Hemisphere should be completely repaired in the 2030s and the gaping Antarctic ozone hole should disappear in the 2060s, according to a scientific assessment released Monday at a conference in Quito, Ecuador. The Southern Hemisphere lags a bit and its ozone layer should be healed by mid-century. …High in the atmosphere, ozone shields Earth from ultraviolet rays that cause skin cancer, crop damage and other problems. Use of man-made chemicals called chlorofluorocarbons (CFCs), which release chlorine and bromine, began eating away at the ozone. In 1987, countries around the world agreed in the Montreal Protocol to phase out CFCs and businesses came up with replacements for spray cans and other uses. At its worst in the late 1990s, about 10 percent of the upper ozone layer was depleted, said Newman. Since 2000, it has increased by about 1 to 3 percent per decade, the report said. This year, the ozone hole over the South Pole peaked at nearly 9.6 million square miles. That’s about 16 percent smaller than the biggest hole recorded — 11.4 million square miles in 2006. …If nothing had been done to stop the thinning, the world would have destroyed two-thirds of its ozone layer by 2065, Newman said. “I don’t think we can do a victory lap until 2060,” Newman said. “That will be for our grandchildren to do.”…
2016-06-30. Ozone layer on the mend, thanks to chemical ban. By Eric Hand, Science. Excerpt: Since it was discovered in 1985, the Antarctic ozone hole has been a potent symbol of humankind’s ability to cause unintended environmental harm. But now comes a glimmer of good news: The void in the ozone layer is shrinking. “It’s a big surprise,” says Susan Solomon, an atmospheric chemist at the Massachusetts Institute of Technology in Cambridge. “I didn’t think it would be this early.”… http://www.sciencemag.org/news/2016/06/ozone-layer-mend-thanks-chemical-ban
2015-05-26. Quantifying the ozone and ultraviolet benefits already achieved by the Montreal Protocol. By M. P. Chipperfield et al, Nature Communications. Abstract: Chlorine- and bromine-containing ozone-depleting substances (ODSs) are controlled by the 1987 Montreal Protocol. In consequence, atmospheric equivalent chlorine peaked in 1993 and has been declining slowly since then. Consistent with this, models project a gradual increase in stratospheric ozone with the Antarctic ozone hole expected to disappear by ~2050. However, we show that by 2013 the Montreal Protocol had already achieved significant benefits for the ozone layer. Using a 3D atmospheric chemistry transport model, we demonstrate that much larger ozone depletion than observed has been avoided by the protocol, with beneficial impacts on surface ultraviolet. A deep Arctic ozone hole, with column values <120 DU, would have occurred given meteorological conditions in 2011. The Antarctic ozone hole would have grown in size by 40% by 2013, with enhanced loss at subpolar latitudes. The decline over northern hemisphere middle latitudes would have continued, more than doubling to ~15% by 2013…. http://www.nature.com/ncomms/2015/150526/ncomms8233/full/ncomms8233.html
2015-04-28. Ozone Hole to Remain Large During Cold Years. By Eric Betz, EOS Earth and Space Science News. Excerpt: Despite the Montreal Protocol’s success, it will take years of observations to be sure that regulations are allowing the ozone hole to recover. …In 1987, the nations of the world negotiated the Montreal Protocol to stop the harmful emissions of CFCs. The hole quit growing by the mid-1990s, but recovery of the protective shield has been slow because many ozone-depleting substances can last in the atmosphere for 50 and even 100 years. Scientists project that the hole will not vanish until around 2070. However, conclusively tying the international regulations to ozone recovery is not straightforward. While CFCs are no longer emitted, scientists calculate that the slow destruction of CFCs already in the atmosphere causes chlorine to decline each year by roughly 20 parts per trillion (ppt), or about 0.5%. However, Earth-orbiting satellites indicate that the natural variability of chlorine levels over Antarctica is up to 10 times larger than the expected annual decline. …According to Strahan et al., it will take a decade of chlorine declines to be certain the Montreal Protocol has caused the ozone hole to shrink. Low temperatures in the Antarctic stratosphere currently play the largest role in determining the size of the ozone hole. In 2006, the combination of very low temperatures and high chlorine levels produced the largest ozone hole ever. By 2040, the authors expect that chlorine levels will have fallen enough that the ozone hole will be smaller than it is today even during a very cold year. The authors say it is unlikely any future ozone hole will grow to 2006 levels…. https://eos.org/research-spotlights/ozone-hole-to-remain-large-during-cold-years
2014-07. The Antarctic ozone hole: An update. For GSS Ozone chapter 9. Excerpt: In the 30 years since the ozone hole was discovered, our understanding of the polar atmosphere has become much more complete. The worldwide response to the discovery was fast, but the recovery is slow. …Although anthropogenic CFCs are emitted mostly in the Northern Hemisphere, they are well mixed throughout the troposphere over the course of a couple of years, and air that enters the stratosphere in the tropics carries with it tropospheric levels of CFCs. …Although the Arctic and Antarctic are similar in some ways, ozone columns below 180 DU, routine in the Antarctic, have never been observed in the Arctic. Chlorine levels are similar in both hemispheres, but winter and spring temperatures in the Antarctic are much colder than in the Arctic. …The Northern Hemisphere’s large mountain ranges and its broad contrasts between land and sea temperatures result in a weaker polar vortex, warmer temperatures, and stronger Brewer–Dobson circulation. That stronger circulation leads to greater transport of ozone to the Arctic lower stratosphere and naturally higher ozone; year-to-year variability is also greater than in the Southern Hemisphere…. http://scitation.aip.org/content/aip/magazine/physicstoday/article/67/7/10.1063/PT.3.2449. By Anne R. Douglass, Paul A. Newman and Susan Solomon, Physics Today.
2013-10-25. Antarctic Ozone Hole Slightly Smaller than Average This Year. Excerpt: The ozone hole that forms each year in the stratosphere over Antarctica was slightly smaller in 2013 than average in recent decades, according to NASA satellite data. …However, the size of the hole in any particular year is not enough information for scientists to determine whether a healing of the hole has begun. …The ozone hole forms when the sun begins rising again after several months of winter darkness. Polar-circling winds keep cold air trapped above the continent, and sunlight-sparked reactions involving ice clouds and chlorine from manmade chemicals begin eating away at the ozone. Most years, the conditions for ozone depletion ease before early December when the seasonal hole closes. See image…. http://www.nasa.gov/press/2013/october/antarctic-ozone-hole-slightly-smaller-than-average-this-year/. NASA RELEASE 13-316.
2012-11-22. Effort to Curb Coolant Falters, Sometimes at Home | by ELISABETH ROSENTHAL and ANDREW W. LEHREN, NY Times. Excerpt: …The Environmental Protection Agency has tried to reduce use of …HCFC-22, which depletes the ozone layer and contributes to global warming, by imposing strict quotas on its production. Since 2010, it has also banned the sale of new air-conditioning units containing the compound, and has promoted recycling of the gas from old machines so it will not be released. But … at Mr. Spector’s home circumvented all the agency’s rules and good intentions: Instead of finding and repairing the hole in his aging unit, a complicated task, a serviceman pumped in more coolant, which leaked out by the next day. When Mr. Spector called around for another solution, a salesman offered to swap in a new condenser unit, but one that still used HCFC-22 — meaning one more American home would continue relying on an environmentally damaging coolant for years. HCFC-22 is being phased out of air conditioners worldwide under an international treaty called the Montreal Protocol, and the United States has aggressively pressed poor countries to pick up the pace. But the United States has yet to put its own house in order. And, with 140 million central air units still running on HCFC-22 in this country, it is a major offender. …Regulatory loopholes allow manufacturers to sell parts that rely on HCFC-22, so systems using the old gas can be refurbished rather than replaced. There is almost no reclamation of the gas from old machines for recycling. The E.P.A. is behind schedule in imposing rules to ratchet down domestic production, and smuggling is rarely detected. Even where there are regulations — for example, repair technicians are legally bound to collect old gas rather than vent it — there is little enforcement. …. Read the full article: http://www.nytimes.com/2012/11/23/science/earth/air-conditioner-repairs-undermine-coolant-restrictions.html?nl=todaysheadlines&emc=edit_th_20121123
2012 October 24. 2012 Antarctic Ozone Hole Second Smallest in 20 Years. By Steve Cole and Katy Human, The NY Times. Excerpt: WASHINGTON — The average area covered by the Antarctic ozone hole this year was the second smallest in the last 20 years, according to data from NASA and National Oceanic and Atmospheric Administration (NOAA) satellites. Scientists attribute the change to warmer temperatures in the Antarctic lower stratosphere…This year also showed a change in the concentration of ozone over the Antarctic. The minimum value of total ozone in the ozone hole was the second highest level in two decades. Total ozone, measured in Dobson units (DU), reached 124 DU on Oct. 1. NOAA ground-based measurements at the South Pole recorded 136 DU on Oct. 5. When the ozone hole is not present, total ozone typically ranges from 240-500 DU.…
2012-09-08. As Coolant Is Phased Out, Smugglers Reap Large Profits | Elizabeth Rosenthal and Andrew W. Lehren, The New York Times. Excerpt: MIAMI — The chief executive of the century-old company from America’s heartland shifted nervously on the witness stand here as he tried to explain how a trusted senior vice president had been caught on a wiretap buying half a million dollars in smuggled merchandise, much of it from China. But the contraband purchased by Marcone, a St. Louis-based company that claims to be the nation’s largest authorized source for appliance parts, was not counterfeit handbags or fake medicines. It was a colorless gas that provides the chill for air-conditioners from Miami to Mumbai, from Bogotá to Beijing. Under an international treaty, the gas, HCFC-22, has been phased out of new equipment in the industrialized world because it damages the earth’s ozone layer and contributes to global warming. There are strict limits on how much can be imported or sold in the United States by American manufacturers. But the gas is still produced in enormous volumes and sold cheaply in China, India and Mexico, among other places in the developing world, making it a profitable if unlikely commodity for international smugglers…. Read the full article: http://www.nytimes.com/2012/09/08/science/earth/smugglers-sell-coolant-tied-to-global-warming.html
2012 July 26. Storms Threaten Ozone Layer Over U.S. By Henry Fountain, The NY Times. Excerpt: Strong summer thunderstorms that pump water high into the upper atmosphere pose a threat to the protective ozone layer over the United States, researchers said on Thursday, drawing one of the first links between climate change and ozone loss over populated areas. In a study published online by the journal Science, Harvard University scientists reported that some storms send water vapor miles into the stratosphere — which is normally drier than a desert — and showed how such events could rapidly set off ozone-destroying reactions with chemicals that remain in the atmosphere from CFCs, refrigerant gases that are now banned. The risk of ozone damage, scientists said, could increase if global warming leads to more such storms…Ozone helps shield people, animals and crops from damaging ultraviolet rays from the sun. Much of the concern about the ozone layer has focused on Antarctica, where a seasonal hole, or thinning, has been seen for two decades, and the Arctic, where a hole was observed last year. But those regions have almost no population. A thinning of the ozone layer over the United States during summers could mean an increase in ultraviolet exposure for millions of people and a rise in the incidence of skin cancer, the researchers said….
2012 June 14. American Seafoods pays penalty for ozone-depleting gas | by Johanna Somers, Seattle Times business reporter. Excerpt: The big Seattle seafood processor will pay $700,000 in penalties and spend $9 million to $15 million to switch several ships’ refrigerant systems under an agreement with the EPA….”We think the penalty is fair and it’s something we are prepared to pay,” said Matthew Latimer, chief legal officer for American Seafoods. He said converting the ships to newer refrigeration systems “is something we are required to do anyway by 2020 so we are just excelling the deadline.” The company has already converted two of six ships, he said…. Read the full article: http://seattletimes.nwsource.com/html/businesstechnology/2018436906_seafood15.html
2012-05-09. Jordan Finally Phases out Ozone-depleting Chemicals | by Laurie Balbo, Green Prophet. Excerpt: The Hashemite Kingdom of Jordan has wrapped up a national phase-out of all central cooling systems using chlorofluorocarbons (CFC), reports the Jordan Times: “Jordan’s program for phasing out the use of CFCs, aimed at disposing 1500 tons of the harmful substance, was achieved one year ahead of schedule”, said Ghazi Odat, Director of the Ministry of Environment’s ozone project. Odat said replacing these systems in 165 facilities also reduced energy consumption. The program was funded by a $2.16 million grant from the Multilateral Fund for the Implementation of the Montreal Protocol, granted to the Kingdom in May 2010. Jordan is a signatory to the Montreal Protocol.…. Read the full article: http://www.greenprophet.com/2012/05/jordan-ozone/
2011 November 21. Climate concerns as ‘ozone-friendly’ HFCs use grows. By Mark Kinver, BBC News. Excerpt: …A rise in the use of “ozone-friendly” HFCs (hydroflourocarbons) has prompted experts to voice concerns that the potent greenhouse gases could be a problem in the future. A UN report says that HFCs, many more times potent than CO2, could account for up to 20% of emissions and hamper efforts to curb climate change. They are widely used in fridges and air conditioning, replacing CFCs (chloroflourocarbons) and HCFCs (hydroflourochlorocarbons) that damage the Earth’s ozone layer…”While these ‘replacement for replacement’ chemicals cause near zero damage to the ozone layer, they are powerful greenhouse gases in their own right,” observed Achim Steiner, Unep executive director….
2010 May 6. Whatever Happened to the Hole in the Ozone Layer? By Stuart Fox, LiveScience. Excerpt: …Today, the ozone hole – actually a region of thinned ozone, not actually a pure hole – doesn’t make headlines like it used to. The size of the hole has stabilized, thanks to decades of aerosol-banning legislation. But, scientists warn, some danger still remains.
First, the good news: Since the 1989 Montreal Protocol banned the use of ozone-depleting chemicals worldwide, the ozone hole has stopped growing. Additionally, the ozone layer is blocking more cancer-causing radiation than any time in a decade because its average thickness has increased, according to a 2006 United Nations report. Atmospheric levels of ozone-depleting chemicals have reached their lowest levels since peaking in the 1990s, and the hole has begun to shrink.
Now the bad news: The ozone layer has also thinned over the North Pole. This thinning is predicted to continue for the next 15 years due to weather-related phenomena that scientists still cannot fully explain, according to the same UN report . And, repairing the ozone hole over the South Pole will take longer than previously expected, and won’t finish until between 2060 and 2075….
2010 April 21. Ozone’s joined-up climate. By Richard Black, BBC News. Excerpt: Remember the unseemly rush to biofuels? The sudden impetus from all kinds of bodies including UN institutions, the EU, and governments such as the UK that began about four years ago to ramp up the growing of fuel crops and to adopt liquids made from them as the low-carbon transport panacea?
While the enthusiasm was understandable…, the thinking was also full of holes.
Some biofuel systems would actually increase emissions, peoples’ rights (particularly in rural areas of developing countries) were potentially compromised, and the impacts on biodiversity of coating the surface of the planet in monocrop plantations were also potentially horrible.
…More holistic thinking – more integrated thinking structures at national and international level – would perhaps have ensured that the downsides were seen earlier in the day, and there would have been no over-eager policy-making and subsequent retrenchment.
Something potentially analogous has been happening with the international agreements that are supposed to deal with climate change and ozone depletion – the UN climate convention (UNFCCC) and the Montreal Protocol.
The latter has met with some success at progressively phasing out ozone-destroying chemicals such as cholorofluorocarbons (CFCs) and methyl bromide.
…However, there’s been a problem. The replacement chemicals, HCFCs, are – like CFCs themselves – potent greenhouse gases; molecule for molecule they are thousands of times more potent than carbon dioxide. They also cause some ozone depletion, though far less than CFCs.
…But the most likely replacements for HCFCs – HFCs – would still contribute substantially to the man-made greenhouse.
One study published last year concluded that if there were to be a meaningful global agreement to tackle greenhouse gases such as CO2, then by 2050, HFCs could be contributing anywhere between 9% and 45% to the man-made greenhouse effect….
2010 Jan 25. The Ozone Hole Is Mending. Now for the ‘But.’ By Sindya N. Bhanoo, The NY Times. Excerpt: That the hole in Earth’s ozone layer is slowly mending is considered a big victory for environmental policy makers. But in a new report, scientists say there is a downside: its repair may contribute to global warming.
It turns out that the hole led to the formation of moist, brighter-than-usual clouds that shielded the Antarctic region from the warming induced by greenhouse gas emissions over the last two decades, scientists write in Wednesday’s issue of Geophysical Research Letters….
2009 June 22. Ozone Solution Poses a Growing Climate Threat. By Andrew C. Revkin, The NY Times. Excerpt: A group of chemicals called hydrofluorocarbons, long hailed as a substitute for gases that can destroy the ozone layer, are now seen as a growing greenhouse threat given their outsize ability to warm the atmosphere.
The chemicals, mainly referred to by the acronym HFC’s, have long been known to be potent heat-trapping substances. But because they are released in tiny traces, they currently contribute less than 1 percent of the climate-warming effect from human-generated carbon dioxide.
But fast-paced growth in the use of these chemicals as refrigerants and in air conditioning in developing countries is poised to make HFC’s a far bigger contributor to warming, scientists are saying. A sobering new analysis of HFC emission trends, published Monday in the Proceedings of the National Academy of Sciences, forecasts that by midcentury, emissions of these chemicals could be heating the atmosphere with the same punch as 7 or 8 billion tons a year of carbon dioxide….
The rising importance of HFC’s has some climate campaigners, and countries, calling for a new use for an old treaty, the Montreal Protocol regulating substances harming the ozone layer. Because the gas is so similar to chemicals already being phased out under that treaty, it would not be hard to get countries to consider limiting its emissions under that pact….
2009 March 18. New Simulation Shows Consequences of a World Without Earth’s Natural Sunscreen. By Michael Carlowicz, NASA’s Goddard Space Flight Center. Excerpt: The year is 2065. Nearly two-thirds of Earth’s ozone is gone — not just over the poles, but everywhere. The infamous ozone hole over Antarctica, first discovered in the 1980s, is a year-round fixture, with a twin over the North Pole. The ultraviolet (UV) radiation falling on mid-latitude cities like Washington, D.C., is strong enough to cause sunburn in just five minutes. DNA-mutating UV radiation is up 650 percent, with likely harmful effects on plants, animals and human skin cancer rates.
Such is the world we would have inherited if 193 nations had not agreed to ban ozone-depleting substances, according to atmospheric chemists at NASA’s Goddard Space Flight Center, Greenbelt, Md., Johns Hopkins University, Baltimore, and the Netherlands Environmental Assessment Agency, Bilthoven.
Led by Goddard scientist Paul Newman, the team simulated “what might have been” if chlorofluorocarbons (CFCs) and similar chemicals were not banned through the treaty known as the Montreal Protocol….
…In the new analysis, Newman and colleagues “set out to predict ozone losses as if nothing had been done to stop them.”…
…By the simulated year 2020, 17 percent of all ozone is depleted globally, as assessed by a drop in Dobson Units (DU), the unit of measurement used to quantify a given concentration of ozone. An ozone hole starts to form each year over the Arctic, which was once a place of prodigious ozone levels.
By 2040, global ozone concentrations fall below 220 DU, the same levels that currently comprise the “hole” over Antarctica. (In 1974, globally averaged ozone was 315 DU.) The UV index in mid-latitude cities reaches 15 around noon on a clear summer day (a UV index of 10 is considered extreme today.), giving a perceptible sunburn in about 10 minutes. Over Antarctica, the ozone hole becomes a year-round fixture.
…”We simulated a world avoided,” said Newman, “and it’s a world we should be glad we avoided.”…
2008 June 13. Mending Ozone Hole May Benefit Climate Change. By David Biello, Scientific American. Excerpt: Decades of chemical pollution have damaged the ozone layer of the upper atmosphere that shields Earth from the harmful effects of the sun’s ultraviolet rays, each summer eating a hole over the South Pole that expands to nearly the size of Antarctica. But since 1996, when an international treaty banned the culprit chemical refrigerants and propellants (known as CFCs, or chlorofluorocarbons), the size of the seasonal tear has been shrinking—and scientists predict it may stop forming by the end of this century.
That is not just good news for the ozone hole, it is also good news for the climate. Atmospheric scientists note in a new study published in Science that sewing up the rift in the ozone (a type of oxygen) layer may help heal another environmental woe: climate change.
The reason: closing the gash may affect the flow of winds known as the westerlies around Antarctica, which impact everything from the extent of sea ice to the location of deserts in the Southern Hemisphere.
“The winds drive everything,” says study author Lorenzo Polvani, an atmospheric scientist at Columbia University, “locations of storms, dry zones and deserts, the ice and the ocean circulation as well as the carbon uptake of the oceans.” For decades, these winds have been speeding up near Antarctica; repairing the ozone would weaken the winds, he says, and shift them back toward the equator, affecting weather in the entire Southern Hemisphere, including Antarctica as well as Australia, parts of Africa and South America.
This also means Earth’s southernmost continent might experience warming in future as the winds continue to shift and allow relatively warmer air to cover it, potentially speeding the melting of ice shelves. In addition, if there were no hole, the replenished ozone would trap even more heat as greenhouse gas concentrations also rise, according to Polvani.
2008 Apr 24. Stratospheric Injections to Counter Global Warming Could Damage Ozone Layer. NCAR Press Release. Excerpt: BOULDER–A much-discussed idea to offset global warming by injecting sulfate particles into the stratosphere would have a drastic impact on Earth’s protective ozone layer, new research concludes. The study, led by Simone Tilmes of the National Center for Atmospheric Research (NCAR), warns that such an approach might delay the recovery of the Antarctic ozone hole by decades and cause significant ozone loss over the Arctic.
…In recent years, climate scientists have studied “geoengineering” proposals to cool the planet and mitigate the most severe impacts of global warming. Such plans could be in addition to efforts to reduce greenhouse gas emissions. One of the most-discussed ideas, analyzed by Nobel laureate Paul Crutzen and other researchers, would be to regularly inject large amounts of Sun-blocking sulfate particles into the stratosphere. The goal would be to cool Earth’s surface, much as sulfur particles from major volcanic eruptions in the past have resulted in reduced surface temperatures.
…”Our research indicates that trying to artificially cool off the planet could have perilous side effects,” Tilmes says. “While climate change is a major threat, more research is required before society attempts global geoengineering solutions.”
…Since major volcanic eruptions temporarily thin the ozone layer in the stratosphere, Tilmes and her colleagues looked into the potential impact of geoengineering plans on ozone over the poles. Sulfates from volcanoes provide a surface on which chlorine gases in the cold polar lower stratosphere can become activated and cause chemical reactions that intensify the destruction of ozone molecules, although the sulfates themselves do not directly destroy ozone.
The new study concluded that, over the next few decades, hypothetical artificial injections of sulfates likely would destroy between about one-fourth to three-fourths of the ozone layer above the Arctic.
Title: The sensitivity of polar ozone depletion to proposed geo-engineering schemes Authors: Simone Tilmes, Rolf Mueller, and Ross Salawitch Publication: Science Express, April 24, 2008
7 December 2005. Scientists Say Recovery of the Ozone Layer May Take Longer Than Expected. By KENNETH CHANG, NY Times. SAN FRANCISCO, Dec. 6 – The layer of ozone in the earth’s upper atmosphere, which protects life from harmful ultraviolet radiation but which has been damaged by artificial chemicals, may take a decade or two longer to recover than previously thought, scientists reported Tuesday. Until now, the ozone layer had been expected to return to its 1980 condition by about 2050. But at a meeting of the American Geophysical Union here, the scientists said new measurements and computer simulations suggested that continuing use of the chemicals – chlorofluorocarbons, or CFC’s – would delay the recovery until about 2065. Despite a ban on producing the chemicals in industrialized countries and the ready availability of substitute chemicals, the United States and Canada still account for about 15 percent of current emissions, because CFC’s are still in use in older refrigerators and air-conditioners….
28 September 2005. The Role of Science in Environmental Policy Making. Testimony of The Honorable Richard E. Benedick, Ambassador, ret. to the United States Senate Committee on Environment & Public Works. “The Case of the Montreal Protocol: Science Serving Public Policy” This testimony pertains to efforts to solve the ozone hole problem, but has lesson for other policy issues, such as actions regarding climate change or loss of biodiversity.
Nov. 14, 2003. NAIROBI, Kenya, U.S. Fails to Gain Exemption on Ozone-Harming Chemical, By THE ASSOCIATED PRESS – Negotiators from the European Union and poor countries refused on Friday to exempt the United States from a requirement to phase out chemicals that destroy the ozone layer. For direct link, click here. [to access NY Times articles online, you must register with them, no charge.]
November 10, 2003. NY Times. At Meetings, U.S. to Seek Support for Broad Ozone Exemptions, By ANDREW C. REVKIN. The two-decade effort to eliminate chemicals that harm the ozone layer faces its most serious test in recent years this week as the Bush administration seeks international support for broad exemptions to a 2005 ban on a popular pesticide. Many American farmers say the pesticide, methyl bromide, is vital as they try to compete with farm production in countries where fields are tended by low-paid laborers. Critics of the proposed exemptions, led by the European Union, say that substitute chemicals are already in wide use and that the American request threatens progress toward repairing the ozone layer, which shields the earth from radiation that causes cancers and other problems. For direct link, click here. [to access NY Times articles online, you must register with them, no charge.]
Commercial products that “cleanse the air by producing ozone:
- http://www.filterfactory.com/purifiers/ — ths site discusses safe levels of ozone concentrations, which differs from the EPA’s recommendation below…
Assessments of ozone purifiers: