bromines
Energy-efficient green buildings may emit hazardous chemicals.
Newly renovated low-income housing units in Boston earned awards for green design and building but flunked indoor air-quality tests, a new study shows.
(Reuters Health) - Newly renovated low-income housing units in Boston earned awards for green design and building but flunked indoor air-quality tests, a new study shows.
Researchers found potentially carcinogenic levels of toxic chemicals in the remodeled homes before and after residents moved in. All of the 30 eco-friendly homes in the study had risky indoor air concentrations for at least one chemical.
“Even in green buildings, building materials contain chemicals that we’re concerned about from a health perspective,” said lead author Robin Dodson, a researcher at Silent Spring Institute in Newton, Massachusetts.
“We should not only think about the efficiency of the building but the health of the building,” she said in a phone interview.
The hazards seemed to come both from materials used to renovate the housing units as well as from occupants’ furnishings and personal-care products, the study found.
“Synthetic chemicals are ubiquitous in modern life,” said co-author Gary Adamkiewicz, an environmental health professor at Harvard T.H. Chan School of Public Health in Boston.
“They’re in new housing, old housing, green housing, conventional housing and high- and low-income housing,” he said by email.
As reported in Environment International, Dodson, Adamkiewicz and colleagues collected air and dust samples from 10 renovated units before occupancy and from 27 units one to nine months after residents moved in between July 2013 and January 2014.
By testing the homes before and after they were occupied, investigators were able to trace the presence of nearly 100 chemicals with known or suspected health concerns to the renovation, the residents or a combination.
Both before and after occupancy, all the tested units had indoor air concentrations of formaldehyde that exceeded the U.S. Environmental Protection Agency’s cancer-based screening level.
The researchers expected formaldehyde, which has been associated with allergy and asthma, might leach out of building materials, and they found evidence that it did. But because formaldehyde emissions remained high after occupancy, the research team suspected that residents also brought formaldehyde in personal-care products.
Researchers also believe that flame retardants, which are suspected of causing cancer and diminishing male fertility, had been added to the building insulation.
To their surprise, they found chemicals used in sunscreen, nail polish and perfumes being emitted from building materials, possibly because they had been added to paint or floor finishes, Dodson said.
Residents appear to have brought into the renovated homes a number of health-disturbing chemicals, including antimicrobials, flame retardants, plastics and fragrances.
Flame retardant BDE-47, which appeared after residents moved in, has been banned since 2005. Dodson assumes residents carried the compound into their homes, possibly in second-hand furniture.
Consumers could improve household air quality by using products free of fragrance and other seemingly innocuous but harmful ingredients, Dodson said. But the onus should not be on consumers, she said.
“Why are manufacturers even allowed to use these chemicals in their products?” she said.
Green building standards should be broadened to prohibit use of hazardous chemicals, she said.
Tom Lent, policy director of the nonprofit Healthy Building Network in Berkeley, California, said the study provides important clues about which hazardous chemicals are being released from building materials so that green buildings can be constructed to be both energy-efficient and healthy.
“There does not need to be a conflict,” Lent, who was not involved with the study, said in an email.
But the conflict between energy-efficient building and the need to reduce toxic indoor air emissions has existed for 15 years, Asa Bradman said by email. Bradman, associate director of the Center for Environmental Research and Children’s Health at the University of California, Berkeley, was not involved with the study.
Adamkiewicz recently completed another study that suggests green buildings can be healthy, or at least healthier, he said.
He studied families who moved from old, conventional housing to new, green public housing units in Boston. The new buildings were designed to save energy and reduce exposures to indoor pollutants.
In the green units, adults wheezed and coughed less and suffered fewer headaches, he found, and children missed fewer school days and had fewer asthma attacks and hospitalizations.
SOURCE: bit.ly/2wZx8zN Environment International, online September 12, 2017.
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Thirty years after Montreal pact, solving the ozone problem remains elusive.
Did the Montreal Protocol fix the ozone hole? It seemed so. With chlorofluorocarbons (CFCs) and other ozone-eating chemicals banned, many scientists said it was only a matter of time before the ozone layer recharged, and the annual hole over Antarctica healed for good.
ANALYSIS
Thirty Years After Montreal Pact, Solving the Ozone Problem Remains Elusive
Despite a ban on chemicals like chlorofluorocarbons, the ozone hole over Antarctica remains nearly as large as it did when the Montreal Protocol was signed in 1987. Scientists now warn of new threats to the ozone layer, including widespread use of ozone-eating chemicals not covered by the treaty.
BY FRED PEARCE • AUGUST 14, 2017
Did the Montreal Protocol fix the ozone hole? It seemed so. With chlorofluorocarbons (CFCs) and other ozone-eating chemicals banned, many scientists said it was only a matter of time before the ozone layer recharged, and the annual hole over Antarctica healed for good.
But 30 years on, some atmospheric chemists are not so sure. The healing is proving painfully slow. And new discoveries about chemicals not covered by the protocol are raising fears that full recovery could be postponed into the 22nd century – or possibly even prevented altogether.
In mid-September, the United Nations is celebrating the protocol’s 30th anniversary. It will declare that “we are all ozone heroes.” But are we patting ourselves on the back a bit too soon?
The ozone layer is a long-standing natural feature of the stratosphere, the part of the atmosphere that begins about six miles above the earth. The ozone layer filters out dangerous ultraviolet radiation from the sun that can cause skin cancer and damage many life forms. It may have been essential for the development of life on Earth.
So there was alarm in the 1970s when researchers first warned that extremely stable man-made compounds like CFCs, used in refrigerants and aerosols, were floating up into the stratosphere, where they released chlorine and bromine atoms that break down ozone molecules. In the 1980s, Antarctic researchers discovered that these chemical reactions went into overdrive in the super-cold polar stratospheric clouds that formed over the frozen continent. They had begun creating a dramatic “hole” in the ozone layer at the end of each austral winter.
The ensuing panic resulted in the signing of the Montreal Protocol on September 16, 1987. It and its successors have phased out production of a range of man-made chlorine and bromine compounds thought to persist for the several years needed for them to reach the stratosphere. Besides CFCs, they include carbon tetrachloride, hydrochlorofluorocarbons (HCFCs), and methyl bromide, a fumigant once widely used to kill pests.
So far so good. The amount of ozone-depleters in the atmosphere has dropped by more than 10 percent since peaking in the late 1990s. In response, the total ozone in the atmosphere has been largely unchanged since 2000.
Satellite imagery depicting the annual maximum extent of the ozone hole over Antarctica from 1979 to 2013. Credit: NASA GODDARD SPACE FLIGHT CENTER
But in the past five years, evidence has emerged that potential ozone-eating compounds can reach the ozone layer much faster than previously thought. Under some weather conditions, just a few days may be enough. And that means a wide range of much more short-lived compounds threaten the ozone layer – chemicals not covered by the Montreal Protocol.
These compounds are all around us. They are widely used as industrial solvents for tasks like degreasing and dry cleaning. And their releases into the atmosphere are increasing fast.
These new ozone-busters include dichloromethane (DCM), a common and cheap paint stripper, also used in foam-blowing agents and, ironically, in the manufacture of “ozone-friendly” alternatives to CFCs. With emissions now exceeding one million tons a year, the concentration of DCM in the lower atmosphere has more than doubled since 2004. Even so, it has not been regarded as a threat to the ozone layer, because its typical lifetime in the atmosphere before it is broken down in photochemical reactions is only about five months. It should, atmospheric chemists concluded, remain safely in the lower atmosphere.
But that view collapsed in 2015, when Emma Leedham Elvidge at the University of East Anglia in England examined air samples taken on board commercial aircraft cruising at the lower edge of the stratosphere. She found high levels of DCM, especially over the Indian subcontinent and Southeast Asia, and particularly during the Asian monsoon season, when strong updrafts fast-track air from the ground to the stratosphere. It seems they were taking DCM along for the ride.
Alarm bells are ringing about dozens of other short-lived ozone-destroying chlorine compounds accumulating in the atmosphere.
How much should we worry? Ryan Hossaini, an atmospheric chemist at Lancaster University, recently did the math. He calculated that DCM currently contributes less than 10 percent of the chlorine in the ozone layer. But on current emission trends, it could be That could delay the ozone hole’s recovery by 30 years, until at least 2095, he suggested.
Others share that concern. “Growing quantities of DCM are leaking into the stratosphere, where it is exceptionally effective in destroying the ozone,” says David Rowley, an atmospheric chemist at the University College London, who was not involved in the research. “The potential for DCM to affect the global ozone budget is profound.”
Alarm bells are ringing about dozens of other short-lived, potentially ozone-destroying chlorine compounds accumulating in the atmosphere as a result of fast-rising global manufacturing. They include 1,2-dichloroethane, a chemical widely used in the manufacture of PVC pipes. There are few atmospheric measurements of this compound yet, “but sporadic data suggest it is a significant source of chlorine in the atmosphere,” says Hossaini.
The risks of such chemicals reaching the ozone layer are greatest in the tropics, where manufacturing is booming in fast-industrialising countries such as China and India, and where, as luck would have it, atmospheric circulation patterns are favorable. The Asian monsoon can propel the gases to the stratosphere in as little as ten days, according to unpublished research seen by Yale Environment 360.
The movement of ozone-depleting chemicals through the atmosphere, shifting from the tropics and concentrating in Antarctica. NASA GODDARD SPACE FLIGHT CENTER
Thirty years on, the Montreal Protocol has not begun to come to grips with these chemicals, warns Rowley. “The naïve view until recently,” he says, “was that short-lived [chemicals] didn’t present a threat to stratospheric ozone. Wrong.”
Other loopholes in the protocol are concerning researchers as well. In 2014, colleagues of Leedham Elvidge’s at the University of East Anglia warned that three CFCs supposedly banned under the protocol were turning up in increasing amounts in the clean air blowing round the Southern Ocean and captured at Cape Grim in Tasmania. Johannes Laube, an atmospheric chemist at the University of East Anglia, calculated that global emissions of CFC-113a, once an important feedstock in manufacturing both refrigerants and pyrethroid pesticides, doubled in two years.
How come? It turns out that the Montreal Protocol never completely banned CFCs. “CFC-113a is covered by a loophole that allows industries to apply for exemptions,” Laube says. Confidentiality clauses in the treaty about these exemptions mean that “we simply don’t know if we have found exempted emissions, or if they are from some illegal manufacture somewhere. Either way, they are increasing fast, which makes this worrying.” Trade in banned ozone-depleting chemicals has declined in the past decade, but remains a problem, and has been documented particularly for hydrochlorofluorocarbons.
Scientists knew recovery of the ozone layer would take time because of the long lifetimes of many of the dangerous compounds we unleashed in past decades. But last year, Susan Solomon of MIT – who back in the 1980s became one of the world’s most celebrated scientists for uncovering the chemistry of the polar stratospheric clouds — declared that she had detected the first “fingerprints” of the hole closing. “The onset of healing of Antarctic ozone loss has now emerged,” she wrote.
“The signature of ozone recovery is not quite there yet,” says one expert.
But other researchers remain cautious. There have been some recent bumper springtime holes in Antarctic ozone. The 2015 hole was the fourth largest since 1991, peaking at an area larger than the continent of North America. It was also deeper than other recent holes and lasted longer. 2016 was also worse than average and 2017 is expected to be severe, too.
Solomon blamed 2015 on the Calbuco volcano in Chile, which ejected sulphur particles that enhanced the ozone-destroying properties of polar stratospheric clouds. But Susan Strahan of NASA’s Goddard Space Flight Center warns that the size of the hole in any given year is still dominated by year-to-year variations in the temperature of the stratosphere and the vagaries of meteorology. “The signature of ozone recovery is not quite there yet,” she says, adding that day will come, but we may have to wait until the 2030s.
Meanwhile at the other end of the planet, ozone losses over the Arctic may still be worsening. The Arctic is less susceptible to the formation of ozone holes than Antarctica, because the weather is messier. The stable air that causes the ultra-cold conditions where polar stratospheric clouds form in Antarctica is much less likely. But it does happen whenever temperatures get cold enough for polar stratospheric clouds to form.
A deep hole briefly formed over the Arctic in 2011. In places, more than 80 percent of the ozone was destroyed, twice the loss in the worst previous years, 1996 and 2005. In both the past two winters, researchers saw polar stratospheric clouds over parts of Britain, says Jonathan Shanklin of the British Antarctic Survey. But they were brief and did not lead to major ozone loss.
Shanklin says an important reason for the sluggish recovery of the ozone layer is global warming. As increased levels of greenhouse gases such as carbon dioxide trap more solar heat radiating from the Earth’s surface, less warmth reaches the stratosphere, which cools as a result. This trend has been evident for almost 40 years. A colder stratosphere improves conditions for ozone loss. Climate change “could delay the recovery of the ozone hole well into the second half of this century,” he says.
Protecting the ozone layer “presents a much greater industrial and political challenge than previously thought,” says one researcher.
Should we be frightened? Some of the crazier hype in the early days of the ozone hole – like blind sheep in Patagonia and collapsing marine ecosystems – proved nonsense. But the raised risk of skin cancers from the extra ultraviolet radiation streaming through the thinned ozone layer is real enough – particularly for reckless white-skinned sunbathers. The ozone layer is still as thin as it was 30 years ago.
The good news is that without the Montreal Protocol things would have been a great deal worse, says Martyn Chipperfield, an atmospheric chemist at the University of Leeds. The Antarctic hole would be 40 percent bigger than it is; the ozone layer over Europe and North America would be 10 percent thinner; the 2011 Arctic hole would have been Antarctic-sized; and we would be looking at about two million more cases of skin cancers by 2030, according to research conducted by Chipperfield and colleagues.
Even so, the idea that the Montreal Protocol is doing its job and the recovery is under way begins to look complacent. If emissions of uncontrolled ozone-depleting chemicals such as DCM continue rising, then the gains could be lost. The answer is obvious. “We should be looking into controlling DCM and other solvents, much in the same way as we did CFCs,” says Leedham Elvidge.
The World Meteorological Organization and other UN agencies overseeing the protocol acknowledge that DCM and other short-lived ozone depleting substances “are an emerging issue for stratospheric ozone,” but the government signatories have yet to take action to limit their emissions.
That would involve getting rid of a far wider range of chemicals than so far done under the protocol. Protecting the ozone layer “presents a much greater industrial and political challenge than previously thought,” says Rowley. Thirty years on, there is evidently still a lot to do.
Fred Pearce is a freelance author and journalist based in the U.K. He is a contributing writer for Yale Environment 360 and is the author of numerous books, including "The Land Grabbers, Earth Then and Now: Potent Visual Evidence of Our Changing World," and "The Climate Files: The Battle for the Truth About Global Warming." MORE ABOUT FRED PEARCE →
TOPICS
Climate
PUBLIC HEALTH
POLLUTION
ENVIRONMENTAL LAW
REGIONS
Antarctica and the Arctic
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Australia emits mercury at double the global average.
A report released this week by advocacy group Environmental Justice Australia presents a confronting analysis of toxic emissions from Australia’s coal-fired power plants.
A report released this week by advocacy group Environmental Justice Australia presents a confronting analysis of toxic emissions from Australia’s coal-fired power plants.
The report, which investigated pollutants including fine particles, nitrogen oxides and sulfur dioxide, also highlights our deeply inadequate mercury emissions regulations. In New South Wales the mercury emissions limit is 666 times the US limits, and in Victoria there is no specific mercury limit at all.
This is particularly timely, given that yesterday the Minamata Convention, a United Nations treaty limiting the production and use of mercury, entered into force. Coal-fired power stations and some metal manufacturing are major sources of mercury in our atmosphere, and Australia’s per capita mercury emissions are roughly double the global average.
In fact, Australia is the world’s sixteenth-largest emitter of mercury, and while our government has signed the Minamata convention it has yet to ratify it. According to a 2016 draft impact statement from the Department of Environment and Energy:
Australia’s mercury pollution occurs despite existing regulatory controls, partly because State and Territory laws limit the concentration of mercury in emissions to air […] but there are few incentives to reduce the absolute level of current emissions and releases over time.
Mercury can also enter the atmosphere when biomass is burned (either naturally or by people), but electricity generation and non-ferrous (without iron) metal manufacturing are the major sources of mercury to air in Australia. Electricity generation accounted for 2.8 tonnes of the roughly 18 tonnes emitted in 2015-16.
Mercury in the food web
Mercury is a global pollutant: no matter where it’s emitted, it spreads easily around the world through the atmosphere. In its vaporised form, mercury is largely inert, although inhaling large quantities carries serious health risks. But the health problems really start when mercury enters the food web.
I’ve been involved in research that investigates how mercury moves from the air into the food web of the Southern Ocean. The key is Antartica’s sea ice. Sea salt contains bromine, which builds up on the ice over winter. In spring, when the sun returns, large amounts of bromine is released to the atmosphere and causes dramatically named “bromine explosion events”.
Essentially, very reactive bromine oxide is formed, which then reacts with the elemental mercury in the air. The mercury is then deposited onto the sea ice and ocean, where microbes interact with it, returning some to the atmosphere and methylating the rest.
Once mercury is methylated it can bioaccumulate, and moves up the food chain to apex predators such as tuna – and thence to humans.
As noted by the Australian government in its final impact statement for the Minamata Convention:
Mercury can cause a range of adverse health impacts which include; cognitive impairment (mild mental retardation), permanent damage to the central nervous system, kidney and heart disease, infertility, and respiratory, digestive and immune problems. It is strongly advised that pregnant women, infants, and children in particular avoid exposure.
Australia must do better
A major 2009 study estimated that reducing global mercury emissions would carry an economic benefit of between US$1.8 billion and US$2.22 billion (in 2005 dollars). Since then, the US, the European Union and China have begun using the best available technology to reduce their mercury emissions, but Australia remains far behind.
But it doesn’t have to be. Methods like sulfur scrubbing, which remove fine particles and sulfur dioxide, also can capture mercury. Simply limiting sulfur pollutants of our power stations can dramatically reduce mercury levels.
Ratifying the Minamata Convention will mean the federal government must create a plan to reduce our mercury emissions, with significant health and economic benefits. And because mercury travels around the world, action from Australia wouldn’t just help our region: it would be for the global good.
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Thirty years after the Montreal Protocol, solving the ozone problem remains elusive.
Scientists warn of new threats to the ozone layer, including widespread use of ozone-eating chemicals not covered by the treaty.
Despite a ban on chemicals like chlorofluorocarbons, the ozone hole over Antarctica remains nearly as large as it did when the Montreal Protocol was signed in 1987. Scientists now warn of new threats to the ozone layer, including widespread use of ozone-eating chemicals not covered by the treaty.
BY FRED PEARCE • AUGUST 14, 2017
Did the Montreal Protocol fix the ozone hole? It seemed so. With chlorofluorocarbons (CFCs) and other ozone-eating chemicals banned, many scientists said it was only a matter of time before the ozone layer recharged, and the annual hole over Antarctica healed for good.
But 30 years on, some atmospheric chemists are not so sure. The healing is proving painfully slow. And new discoveries about chemicals not covered by the protocol are raising fears that full recovery could be postponed into the 22nd century – or possibly even prevented altogether.
In mid-September, the United Nations is celebrating the protocol’s 30th anniversary. It will declare that “we are all ozone heroes.” But are we patting ourselves on the back a bit too soon?
The ozone layer is a long-standing natural feature of the stratosphere, the part of the atmosphere that begins about six miles above the earth. The ozone layer filters out dangerous ultraviolet radiation from the sun that can cause skin cancer and damage many life forms. It may have been essential for the development of life on Earth.
So there was alarm in the 1970s when researchers first warned that extremely stable man-made compounds like CFCs, used in refrigerants and aerosols, were floating up into the stratosphere, where they released chlorine and bromine atoms that break down ozone molecules. In the 1980s, Antarctic researchers discovered that these chemical reactions went into overdrive in the super-cold polar stratospheric clouds that formed over the frozen continent. They had begun creating a dramatic “hole” in the ozone layer at the end of each austral winter.
The ensuing panic resulted in the signing of the Montreal Protocol on September 16, 1987. It and its successors have phased out production of a range of man-made chlorine and bromine compounds thought to persist for the several years needed for them to reach the stratosphere. Besides CFCs, they include carbon tetrachloride, hydrochlorofluorocarbons (HCFCs), and methyl bromide, a fumigant once widely used to kill pests.
So far so good. The amount of ozone-depleters in the atmosphere has dropped by more than 10 percent since peaking in the late 1990s. In response, the total ozone in the atmosphere has been largely unchanged since 2000.
But in the past five years, evidence has emerged that potential ozone-eating compounds can reach the ozone layer much faster than previously thought. Under some weather conditions, just a few days may be enough. And that means a wide range of much more short-lived compounds threaten the ozone layer – chemicals not covered by the Montreal Protocol.
These compounds are all around us. They are widely used as industrial solvents for tasks like degreasing and dry cleaning. And their releases into the atmosphere are increasing fast.
These new ozone-busters include dichloromethane (DCM), a common and cheap paint stripper, also used in foam-blowing agents and, ironically, in the manufacture of “ozone-friendly” alternatives to CFCs. With emissions now exceeding one million tons a year, the concentration of DCM in the lower atmosphere has more than doubled since 2004. Even so, it has not been regarded as a threat to the ozone layer, because its typical lifetime in the atmosphere before it is broken down in photochemical reactions is only about five months. It should, atmospheric chemists concluded, remain safely in the lower atmosphere.
But that view collapsed in 2015, when Emma Leedham Elvidge at the University of East Anglia in England examined air samples taken on board commercial aircraft cruising at the lower edge of the stratosphere. She found high levels of DCM, especially over the Indian subcontinent and Southeast Asia, and particularly during the Asian monsoon season, when strong updrafts fast-track air from the ground to the stratosphere. It seems they were taking DCM along for the ride.
Alarm bells are ringing about dozens of other short-lived ozone-destroying chlorine compounds accumulating in the atmosphere.
How much should we worry? Ryan Hossaini, an atmospheric chemist at Lancaster University, recently did the math. He calculated that DCM currently contributes less than 10 percent of the chlorine in the ozone layer. But on current emission trends, it could be That could delay the ozone hole’s recovery by 30 years, until at least 2095, he suggested.
Others share that concern. “Growing quantities of DCM are leaking into the stratosphere, where it is exceptionally effective in destroying the ozone,” says David Rowley, an atmospheric chemist at the University College London, who was not involved in the research. “The potential for DCM to affect the global ozone budget is profound.”
Alarm bells are ringing about dozens of other short-lived, potentially ozone-destroying chlorine compounds accumulating in the atmosphere as a result of fast-rising global manufacturing. They include 1,2-dichloroethane, a chemical widely used in the manufacture of PVC pipes. There are few atmospheric measurements of this compound yet, “but sporadic data suggest it is a significant source of chlorine in the atmosphere,” says Hossaini.
The risks of such chemicals reaching the ozone layer are greatest in the tropics, where manufacturing is booming in fast-industrialising countries such as China and India, and where, as luck would have it, atmospheric circulation patterns are favorable. The Asian monsoon can propel the gases to the stratosphere in as little as ten days, according to unpublished research seen by Yale Environment 360.
The movement of ozone-depleting chemicals through the atmosphere, shifting from the tropics and concentrating in Antarctica. NASA GODDARD SPACE FLIGHT CENTER
Thirty years on, the Montreal Protocol has not begun to come to grips with these chemicals, warns Rowley. “The naïve view until recently,” he says, “was that short-lived [chemicals] didn’t present a threat to stratospheric ozone. Wrong.”
Other loopholes in the protocol are concerning researchers as well. In 2014, colleagues of Leedham Elvidge’s at the University of East Anglia warned that three CFCs supposedly banned under the protocol were turning up in increasing amounts in the clean air blowing round the Southern Ocean and captured at Cape Grim in Tasmania. Johannes Laube, an atmospheric chemist at the University of East Anglia, calculated that global emissions of CFC-113a, once an important feedstock in manufacturing both refrigerants and pyrethroid pesticides, doubled in two years.
How come? It turns out that the Montreal Protocol never completely banned CFCs. “CFC-113a is covered by a loophole that allows industries to apply for exemptions,” Laube says. Confidentiality clauses in the treaty about these exemptions mean that “we simply don’t know if we have found exempted emissions, or if they are from some illegal manufacture somewhere. Either way, they are increasing fast, which makes this worrying.” Trade in banned ozone-depleting chemicals has declined in the past decade, but remains a problem, and has been documented particularly for hydrochlorofluorocarbons.
Scientists knew recovery of the ozone layer would take time because of the long lifetimes of many of the dangerous compounds we unleashed in past decades. But last year, Susan Solomon of MIT – who back in the 1980s became one of the world’s most celebrated scientists for uncovering the chemistry of the polar stratospheric clouds — declared that she had detected the first “fingerprints” of the hole closing. “The onset of healing of Antarctic ozone loss has now emerged,” she wrote.
“The signature of ozone recovery is not quite there yet,” says one expert.
But other researchers remain cautious. There have been some recent bumper springtime holes in Antarctic ozone. The 2015 hole was the fourth largest since 1991, peaking at an area larger than the continent of North America. It was also deeper than other recent holes and lasted longer. 2016 was also worse than average and 2017 is expected to be severe, too.
Solomon blamed 2015 on the Calbuco volcano in Chile, which ejected sulphur particles that enhanced the ozone-destroying properties of polar stratospheric clouds. But Susan Strahan of NASA’s Goddard Space Flight Center warns that the size of the hole in any given year is still dominated by year-to-year variations in the temperature of the stratosphere and the vagaries of meteorology. “The signature of ozone recovery is not quite there yet,” she says, adding that day will come, but we may have to wait until the 2030s.
Meanwhile at the other end of the planet, ozone losses over the Arctic may still be worsening. The Arctic is less susceptible to the formation of ozone holes than Antarctica, because the weather is messier. The stable air that causes the ultra-cold conditions where polar stratospheric clouds form in Antarctica is much less likely. But it does happen whenever temperatures get cold enough for polar stratospheric clouds to form.
A deep hole briefly formed over the Arctic in 2011. In places, more than 80 percent of the ozone was destroyed, twice the loss in the worst previous years, 1996 and 2005. In both the past two winters, researchers saw polar stratospheric clouds over parts of Britain, says Jonathan Shanklin of the British Antarctic Survey. But they were brief and did not lead to major ozone loss.
Shanklin says an important reason for the sluggish recovery of the ozone layer is global warming. As increased levels of greenhouse gases such as carbon dioxide trap more solar heat radiating from the Earth’s surface, less warmth reaches the stratosphere, which cools as a result. This trend has been evident for almost 40 years. A colder stratosphere improves conditions for ozone loss. Climate change “could delay the recovery of the ozone hole well into the second half of this century,” he says.
Protecting the ozone layer “presents a much greater industrial and political challenge than previously thought,” says one researcher.
Should we be frightened? Some of the crazier hype in the early days of the ozone hole – like blind sheep in Patagonia and collapsing marine ecosystems – proved nonsense. But the raised risk of skin cancers from the extra ultraviolet radiation streaming through the thinned ozone layer is real enough – particularly for reckless white-skinned sunbathers. The ozone layer is still as thin as it was 30 years ago.
The good news is that without the Montreal Protocol things would have been a great deal worse, says Martyn Chipperfield, an atmospheric chemist at the University of Leeds. The Antarctic hole would be 40 percent bigger than it is; the ozone layer over Europe and North America would be 10 percent thinner; the 2011 Arctic hole would have been Antarctic-sized; and we would be looking at about two million more cases of skin cancers by 2030, according to research conducted by Chipperfield and colleagues.
Even so, the idea that the Montreal Protocol is doing its job and the recovery is under way begins to look complacent. If emissions of uncontrolled ozone-depleting chemicals such as DCM continue rising, then the gains could be lost. The answer is obvious. “We should be looking into controlling DCM and other solvents, much in the same way as we did CFCs,” says Leedham Elvidge.
The World Meteorological Organization and other UN agencies overseeing the protocol acknowledge that DCM and other short-lived ozone depleting substances “are an emerging issue for stratospheric ozone,” but the government signatories have yet to take action to limit their emissions.
That would involve getting rid of a far wider range of chemicals than so far done under the protocol. Protecting the ozone layer “presents a much greater industrial and political challenge than previously thought,” says Rowley. Thirty years on, there is evidently still a lot to do.
Keep reading...Show less
Good news: The hole in the ozone layer is finally starting to heal.
Sometimes the world really can get together and avert a major environmental catastrophe before it's too late.
lized that we were rapidly depleting Earth's stratospheric ozone layer, which protects us from the sun's harmful ultraviolet rays.
The culprit? Chlorofluorocarbons (CFCs), a chemical widely used in refrigerators and air conditioners. These chemicals had already chewed a massive "hole" in the ozone layer above Antarctica, and the damage was poised to spread further north.
Without the ozone layer's protection, more and more people would be exposed to UV rays. Skin-cancer rates would have soared in many regions, as they already have in Puentas Arenas, Chile, which lies under the existing ozone hole. Those UV rays would also harm crops and the marine food chain.
Fortunately, this apocalyptic scenario never came to pass. Scientists uncovered the problem in time. And, under the 1987 Montreal Protocol, world leaders agreed to phase out CFCs, despite industry warnings that abolishing the chemicals would impose steep costs. The hole in the ozone layer stopped expanding. The global economy kept chugging along.
Now comes further good news. The latest study, conducted by scientists at MIT and elsewhere, identifies several "fingerprints" suggesting that the ozone layer is on its way toward actually healing. They note that the annual ozone hole that appears above Antarctica in September has shrunk by some 4 million square kilometers since 2000, although there are ups and downs each year due to volcanic eruptions.
This 2014 video from NASA illustrates the healing process, showing the minimum concentration of ozone in the southern hemisphere each year from 1979 to 2013. The process is sluggish: The ozone layer kept thinning in the 1980s and 1990s, even after the big agreement to phase out CFCs. In 2006, another major hole appeared. But recently, the hole has started shrinking and ozone concentrations have started rebounding:
Back in 2014, a UN assessment projected that the ozone layer would fully recover by 2050. "There are positive indications that the ozone layer is on track to recovery towards the middle of the century," said UN Under-Secretary-General Achim Steiner. "The Montreal Protocol — one of the world's most successful environmental treaties — has protected the stratospheric ozone layer and avoided enhanced UV radiation reaching the earth's surface."
Granted, just because the world banded together and saved the ozone layer doesn't ensure that we’ll also do the same for future environmental problems, like global warming. It will almost certainly be harder to reduce our reliance on fossil fuels than it was to curtail our use of CFCs. (For one thing, Dupont developed easy substitutes to CFCs fairly quickly.) But the ozone case remains the best example of international cooperation to halt a slow-moving ecological disaster. And it worked.
We barely dodged a bullet with the ozone layer
It's worth reflecting on what a close call we had with the ozone layer. Scientists in Antarctica first began measuring stratospheric ozone levels in 1957, but it still took decades to realize how dire the situation actually was. Indeed, when researchers found signs of severe ozone depletion in the 1970s, they initially thought their instruments were faulty.
It wasn't until 1974 that chemists Mario Molina and Sherwood Rowland published a paper proposing that rising concentrations of CFCs in the atmosphere could deplete the ozone layer. These stable chemicals were widely used as refrigerants and cleaning solvents. But when CFCs wafted up into the stratosphere, they got ripped apart by UV rays, and the free chlorine atoms would catalytically destroy the ozone there.
This hypothesis was difficult to prove, and it was fiercely disputed by Dupont, the world's biggest manufacturer of CFCs, for many years. But evidence kept accumulating, and by the 1980s, scientists finally had incontrovertible proof that CFCs were to blame. That's also when the massive "hole" over Antarctica received widespread attention. (This hole is a severe thinning of the ozone column throughout the atmosphere during the spring and summer.)
We were lucky that the damage wasn't even greater by that point. Dupont had been using chlorine instead of bromine to create its refrigerants. The two elements were roughly interchangeable for this purpose; it just so happened that chlorine was cheaper. Yet, as Paul Crutzen later observed in his Nobel acceptance speech, bromine is 45 times more effective at destroying ozone. Had Dupont used bromine, the ozone layer might have been damaged beyond repair long before anyone even noticed.
Fortunately, that didn't happen. Under the Montreal Protocol of 1987, the world's nations agreed to phase out the use of CFCs in refrigerators, spray cans, insulation foam and fire suppression. By and large, countries complied. Atmospheric concentrations of chlorine have stabilized and have been declining slowly over time.
In their 2014 report, the UN panel noted that without that agreement, atmospheric levels of ozone-depleting substances might have increased tenfold by mid-century. The resulting ozone loss could have led to 2 million additional cases of skin cancer by 2030 — to say nothing of crop damage or other impacts.
Today, recovery is slow, since there's still chlorine lingering in the stratosphere. The Antarctic hole still appears every spring and summer, even reaching a record size in 2006. And it's not just Antarctica: An especially cold Arctic winter in 2011 led to an ozone hole up north, too.
But the broad picture is encouraging: The ozone layer is on track to bounce back to 1980 levels by around mid-century.
Unexpected side effects of the Montreal Protocol
Meanwhile, there have been a few unexpected side effects of this whole affair.
As a result of the Montreal Protocol, companies and countries stopped using CFCs and started using HFCs (hydrofluorocarbons), which have a much more benign effect on the ozone layer. That seemed like a satisfying solution — at least until global warming became a much more pressing concern.
Both CFCs and HFCs are potent greenhouse gases that help warm the planet. And, on net, swapping out CFCs for HFCs reduced the overall amount of greenhouse gases in the atmosphere (making the Montreal Protocol unintentionally one of the biggest steps we've ever taken to prevent climate change).
But now HFCs are becoming a big climate problem in their own right, especially as air-conditioning becomes more popular in fast-growing countries like China and India. HFCs are up to 10,000 times as effective as carbon-dioxide at trapping heat, and their use is soaring.
"Hydrofluorocarbons (HFCs) do not harm the ozone layer but many of them are potent greenhouse gases," the UN panel noted in 2014. "They currently contribute about 0.5 gigatonnes of CO2-equivalent emissions per year. These emissions are growing at a rate of about 7 percent per year. Left unabated, they can be expected to contribute very significantly to climate change in the next decades."
Many environmental groups have urged world nations to revisit the Montreal Protocol and phase out HFCs in favor of chemicals that — like HFO-1234YF — that are both harmless to the ozone layer and don't warm the planet significantly.
In June 2016, the United States and India reached a side agreement to amend the Montreal Protocol in this fashion. The hope is to get a new international agreement late this year. Many companies in the United States, such as Dupont, Coca-Cola, and Target, have already pledged to shift away from using HFCs as refrigerants and toward more benign alternatives.
Further reading
— Roger Pielke Jr. once wrote a nice essay about why the Montreal Protocol isn’t a great template for efforts to tackle climate change. Relatedly, I wrote a piece here about how the success of the Montreal Protocol in the 1980s arguably led UN climate negotiators astray in trying to craft a similar treaty for global warming.
— Back in June, the US and India agreed to tackle HFCs, a little-known (but potent) climate problem
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Indoor Arctic ocean model may reveal secrets of sea ice.
DUPE, LP.The Arctic is a harsh place, with subzero temperatures and rapidly changing weather conditions.
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Climatewire
Indoor Arctic Ocean Model May Reveal Secrets of Sea Ice
A new project could help improve understanding of how the dwindling sea ice interacts with the atmosphere
Feb 5, 2014 |By Stephanie Paige Ogburn and ClimateWire
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arctic sea ice
Image courtesy of NASA/Kathryn Hansen
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The Arctic is a harsh place, with subzero temperatures and rapidly changing weather conditions.
Those circumstances can make it difficult for researchers to conduct controlled experiments, said Roland von Glasow, an atmospheric chemist and professor at the University of East Anglia, who studies the chemical reactions between Arctic sea ice and the atmosphere.
The scientist has a solution to this. He plans to build an 8-meter-cubed model Arctic Ocean at his university, where he can study how sea ice reacts with the atmosphere from the comfort of his laboratory.
The scientist just received a €2 million ($2.7 million) grant from the European Research Council to construct the sea ice chamber and conduct research on this topic. While there is an open-air experimental sea ice chamber in Canada, von Glasow said he had not heard of an indoor chamber like the one he plans to build.
"Inside [the chamber], I want to have my little lab ocean, and we are going to enclose it so that we can control the atmosphere above the sea water, and then we are just going to freeze the whole thing," he said.
One of the problems von Glasow plans to research involves the chemical reactions between sea ice and the atmosphere.
Unlike ice that forms on freshwater lakes, sea ice contains a significant amount of salt, and some of those salts are released from the ice when it freezes.
Decades ago, researchers discovered that bromine, which comes out of sea ice when it freezes, was reacting with the atmosphere to destroy ground-level ozone. But they still don't know why.
"The question is, how, fundamentally, does that work?" von Glasow said.
Strange, cold, but essential chemistry
Researchers know the reaction is related to first-year sea ice. And now that more of the Arctic sea ice melts away in the summer and then refreezes in the winter, there is more first-year sea ice.
"So the fraction of first-year sea ice is increasing and so also is the area where this strange chemistry is happening," von Glasow said.
He hopes that by mimicking Arctic conditions in the chamber, which should be built in about a year and will reach temperatures from -30 to -20 degrees Celsius (-22 to -4 degrees Fahrenheit), he will be able to learn more about this and other chemical reactions between sea ice and the atmosphere.
"There are still some uncertainties about properties of sea ice, physical and chemical properties. And the hope is that this chamber can contribute to that," von Glasow said.
Paul Shepson, an atmospheric chemist at Purdue University who also researches sea ice chemistry, said the chemistry that occurs in the Arctic is unique, as chlorine, bromine and iodine present in sea salt undergo complex reactions as sea ice freezes and those chemicals are released into the atmosphere.
"We are trying to understand this process in my view somewhat urgently, because sea ice is retreating in the Arctic. In your lifetime, probably, it will be gone," Shepson said.
Shepson said he hoped at some point to take his instruments to von Glasow's new chamber and use it for research.
The opportunity to study the reactions in a controlled environment like von Glasow's chamber is appealing, Shepson said. He pointed out that where he was currently conducting research in Barrow, Alaska, factors like fog and variable light conditions have made the conditions for research less than ideal.
"What Roland is building will be unique on the planet in terms of the ability to not only grow sea ice but to do controlled photochemistry experiments," Shepson said.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
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