Some hydrochlorofluorocarbons HCFCs , transitional substitutes that are less damaging but still harmful to ozone, are still in use. Developing countries need funding from the Montreal Protocol's Multilateral Fund to eliminate the most widely used of these, the refrigerant R The next generation of coolants, hydrofluorocarbons HFCs , do not deplete ozone, but they are powerful greenhouse gases that trap heat, contributing to climate change.
Though HFCs represent a small fraction of emissions compared with carbon dioxide and other greenhouse gases , their planet-warming effect prompted an addition to the Montreal Protocol, the Kigali Amendment , in The amendment, which came into force in January , aims to slash the use of HFCs by more than 80 percent over the next three decades. In the meantime, companies and scientists are working on climate-friendly alternatives, including new coolants and technologies that reduce or eliminate dependence on chemicals.
All rights reserved. Climate Ozone Depletion The ozone layer helps to protect life from harmful ultraviolet radiation. Find out what caused the ozone hole, and how the Montreal Protocol sought to put an end to ozone depletion. Ozone threats and 'the hole' In , Mario Molina and Sherwood Rowland , two chemists at the University of California, Irvine, published an article in Nature detailing threats to the ozone layer from chlorofluorocarbon CFC gases.
Share Tweet Email. Read This Next Wild parakeets have taken a liking to London. Animals Wild Cities Wild parakeets have taken a liking to London Love them or hate them, there's no denying their growing numbers have added an explosion of color to the city's streets.
India bets its energy future on solar—in ways both small and big. Environment Planet Possible India bets its energy future on solar—in ways both small and big Grassroots efforts are bringing solar panels to rural villages without electricity, while massive solar arrays are being built across the country. Epic floods leave South Sudanese to face disease and starvation. Also, from direct measurements over Antarctica, a column ozone level of less than Dobson Units is a result of the ozone loss from chlorine and bromine compounds.
The graphs above show the progress of the ozone hole for The gray shading indicates the highest and lowest values measured since The red numbers are the maximum or minimum values. The stratospheric temperature and the amount of sunlight reaching the south polar region control the depth and size of the Antarctic ozone hole.
The data for the ozone hole area , the minimum ozone , and the minimum stratospheric temperature are available. Also available is a table of values showing the maximum ozone hole area and the minimum ozone values for each year.
Click on the image to get a table of values. The graphs above show the variations of ozone from year to year. What does ardent mean? What kind of literature is a picaresque novel? What does culpable mean? What's a cenotaph? What does gallimaufry mean in The Girl with the Dragon Tattoo? My vocabulary is pretty good, but that one has me stumped! What does it mean to genuflect? Someone told me I was looking wistful. What is wistful? In David Copperfield, what does superannuated mean?
Does the word syllogism have something to do with biology? I see the word benefactor a lot in my reading assignments. Is that somebody who benefits from something? I found a funny word in The Glass Castle. Where did skedaddle come from and what does it mean? Does sinuous mean something like full of sin"? I saw the word in The Devil in the White City.
What are characteristics of Modernist literature, fiction in particular? What does my brother mean when he says he's too ensconced in his studies to look for a girlfriend?
My grandpa complained about a bunch of politicians making what he called chin music. Did he mean they were in a loud band? What is melodrama? In Dracula, what's a missal?
In the terms abject poverty and abject misery, what does abject mean? In Moby-Dick, what does craven mean?
What does cicatrize mean? What is a noisome smell" in Tolstoy's War and Peace? In Jane Eyre, what's syncope? I just read Dracula. What's the forcemeat in Jonathan Harker's journal? Can the word stern mean more than one thing? Where is Yoknapatawpha county? What does smouch mean?
How do you pronounce quay? And what does it mean, anyway? What are some examples of paradox in the novel Frankenstein? In Ivanhoe, what does mammock mean? What does rummage mean? Is a mummer some type of religious person? Some guy I don't like told his friend I was acting all demure. When I complained about our cafeteria food, my biology teacher told me he wished they'd serve agarics.
Was he talking about some kind of dessert? Where did the name Of Mice and Men come from? What genre would you consider the book, The Outsiders? In Fahrenheit , why would a society make being a pedestrian a crime? What does the phrase, a worn-out man of fashion" mean from Jane Eyre? My teacher told me I was being obdurate.
Was that a compliment? What motives inspired Iago to plot revenge against Othello? Who was the first king of Rome? What does enervate mean? What is a parvenu? Is salubrity somehow related to being famous? Do capers have something to do with cops? What's the difference between a soliloquy and a monologue? What's a pandybat? Does the word inexorable have something to do with driving demons out of a person? Do people who prognosticate have some sort of special power?
What is a hegemony, from James Joyce's Ulysses? What are fallow fields? I'm a city gal who heard the term at a 4-H fair and just read it in Anna Karenina.
What's the difference between parody and satire? Lord of the Flies uses the word inimical. I saw vertiginous in Madame Bovary. What does mean the word mean? What does overweening mean, in Don Quixote by Miguel de Cervantes? Can you hear a dirge anyplace but a funeral?
Does imperturbable refer to something you can't break through? What are the seven ages of man? What's dross? What is an injunction? For school I had to make a Napoleon hat, which called for a cockade. What is that? If someone studies assiduously, does it mean they're working really hard or really slowly?
Define mood as it relates to a work of fiction. Distinguish mood from effect. My sister calls me the Princess of Prevarication. This biography I'm reading about Queen Victoria says that she refused to remove the hatchment she had for her husband Prince Albert. What does that word mean? What does sine qua non mean? What's lugubrious mean? What's impugn mean, from Ivanhoe? What does postprandial mean? I love reading fashion magazines and occasionally come across the word atelier.
What does King Lear mean when he says that ingratitude is a marble-hearted fiend"? In Mary Shelley's Frankenstein , what are disquisitions? What's shrive? My neighbor said she's been unshriven for years, but I think her skin looks quite shriveled. What's a dobbin? What's polemic? Over winter break, my uncle told me I was polemic and asked if I was on the debate team at school.
I came across a list of homonyms: mu, moo, moue. I know mu is Greek for the letter m , and moo is the sound cows make, but what's a moue? What does trow mean? In Far from the Madding Crowd , what does cavil mean? Where can I find the word naught in The Scarlet Letter? I found an old diary from the s where the writer describes how he almost died but was saved by a sinapism.
I know what mulch is, but what's mulct? When our teacher was introducing the next reading assignment, he said we'll be using the unexpurgated version. What did he mean? For some reason, the word dingle sticks in my head after having read Treasure Island years ago. I never did discover what it meant. How about it, Cliff? In Dracula , what's stertorous breathing? What does philippic mean? I'm usually pretty good at guessing what words mean, but have no clue about exigence.
What is it? What's doughty? How do you pronounce it? What's sharecropping? I'm kind of embarrassed to ask, because it's one of those words everyone assumes you know what it means. I'm working on my summer reading list with Kafka's The Trial. The very first sentence uses traduce , and I don't know what that means. What does the cormorant bird symbolize in mythology? I saw the word badinage in the book Uncle Tom's Cabin. Do you think that's a typo that really should be bandage?
On a TV modeling contest, a judge said, Her simian walk is unbelievable. In Oliver Twist , Dodger refers to Oliver as flash companion. Can't find a definition of this anywhere. Do elocutionists kill people? For my English homework, I have to write a love poem. I'm only 13 and I haven't had my first love yet. How would I go about writing about feelings that I haven't felt yet?
Where on the body would I find my sarcophagus? What's stolid? It sounds like someone who's stupid and built solid like a wall. What's a wonton person? In which play did William Shakespeare state that misery loves company? What's comfit? Is it a different way of saying comfort? Where did the story Frankenstein by Mary Shelley take place?
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In Tess of the d'Urbervilles, what are thimble-riggers? In Wuthering Heights , what's a thible? Which Hemingway story references the running of the bulls" in Spain? My dad mentioned that his granddad was there for a long time during World War I. If somebody is toady," does it mean they're ugly? In the movie Failure to Launch , there's a line that goes, Well, she certainly is yar," in reference to a yacht. What's yar? I got detention because a teacher said I was being contumacious. What's that?
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I found the word unwonted in a book I'm reading. Is that a typo, you think? In Heart of Darkness , what does cipher mean? In the play The Glass Menagerie, would you describe Tom as selfish? What does Kantian mean, from a philosophical perspective? What's a colonnade? My girlfriend is freaking me out with stories of her dream wedding where she walks down a colonnade. I know this is the least of my problems, but I'm curious. My grandma says she knows how I feel when I knit my brows. Is she crazy?
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Does she think he's from another planet or what? Do you have to have licentiousness to get your driver's license? I ran across the word hardihood in something I read the other day. Is it some kind of clothing?
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Can you explain these quotes from Act 1, Scene 1? In Dostoevsky's Crime and Punishment , what's a samovar? I came across a music channel that featured tejano," and then I saw the same word when I was reading Bless Me, Ultima. But what the heck is prunella?
Is it a purplish color like prunes? In Chapter 2 of Jane Eyre , what are divers parchments? A friend of mine said she hopes to get a counterpane for Christmas. In Wuthering Heights, what does munificent mean? The other day, my dad called my friends a motley crew. Is that his way of saying I should hang out with a different crowd? Why is there an authorship problem with Shakespeare? What is it called when something is out of place in time, like a jet stream in a movie about ancient Rome? In , does Winston die from a bullet at the end of the book or is he in a dream-state?
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I tried to look that up on the Internet but couldn't find anything. Can you help? In The Count of Monte Cristo , does cupidity mean love? I'm guessing that because of, you know, Cupid. Valentine's Day. My theater teacher called me a name the other day. I don't think it was supposed to be a compliment. What's a somnambulist, anyway? Why was Tartuffe such a jerk?
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I'm in a literary dispute over this! What did W. Du Bois mean when he wrote of second-sight? It is these unique conditions through the winter and early spring that result in high ozone destruction over Antarctica. As discussed earlier in this entry , stratospheric ozone plays a fundamental role in protecting surface lifeforms from exposure to harmful levels of UV-B radiation. In the figure we show the average percentage change in UV irradiation reach the surface in relative to levels in Shown are the changes across wavelengths from to nanometres, which is the region where DNA damage from UV irradiation has its largest health impacts.
Here we see that the largest increases in UV irradiation have been at high latitudes — particularly in the South Hemisphere. At nm, for example, irradiance at high Southern latitudes increased by more than 25 percent over this period. At the Northern poles, this was much less at between 5 to 10 percent. Ozone layer protection from UV-B irradiation is critical to the health of many lifeforms, including human health. Ozone depletion and the subsequent increase in UV-B irradiation, as discussed above , can increase negative health impacts such as skin cancer , and other implications such as sunburn and skin ageing.
Using combined ozone, UV and dose-response models, numerous studies have attempted to quantify the potential increase in skin cancer cases as a result of ozone depletion. Such studies also attempt to quantify the number of skin cancer cases avoided as a result of international action through the Montreal Protocol to reduce ODS consumption. Dijk et al. The study estimates that by , two million cases worldwide will be avoided per year as a result of ODS reduction from the Montreal Protocol and its later revisions.
One of the first studies to attempt to quantify excess skin cancer cases, despite being published in the s correlates well with results from recent studies. The primary role of the Vienna Convention, Montreal Protocol and its subsequent revisions was to protect depletion of the stratospheric ozone layer. However, the ambition to reduce and eventually eliminate the use of ozone-depleting substances ODS has also produced co-benefits for greenhouse gas reduction.
With a GWP up to 10, times higher than carbon dioxide CO 2 , these gases can have a notable impact on total greenhouse gas emissions, even in very small concentrations. The reduction in ODS, in particular CFCs has therefore had a significant impact on greenhouse gas reduction in recent years.
In fact, several sources estimate that the climate benefits of the Montreal Protocol have been five to six times that of the Kyoto Protocol.
In the chart we visualize the impact of the reduction in ODS emissions for climate change in terms of greenhouse gas emissions in carbon dioxide equivalents , and radiative forcing measured in watts per square metre.
Blue trends map the estimated impact had the Montreal Protocol not been adopted: it is based on the assumption of a 2 to 3 percent dashed and solid line increase in annual production of halogen substances. The blue area therefore represents the estimated quantity of GHG or radiative forcing averted as a result of the Montreal Protocol. GHG emissions from ODSs in could have reached approximately 10 billion tonnes of CO 2 -equivalents which would have been five times the annual target of the Kyoto Protocol for the period.
If increasing trends of ODSs had continued through to , the WMO project that total GHG emissions from halogen gases could have approximated 20 billion tonnes of CO 2 -equivalents relative to 36 billion tonnes of CO 2 in — this would have been an increase of more than 50 percent to global GHG emissions.
This means HFC emissions have increased notably in recent years. However, HFCs have a large global-warming potential as shown in the table in the Data Definitions section ; and could begin to cancel out climate benefits made by the rapid reduction of CFCs and HCFCs in recent decades. If we are to preserve the climate benefits of the Montreal Protocol, further emissions and potential substitutes for CFC products will be important in the coming years. ODP tonnes attempt to standardise and correct for the differences in the potential ozone destruction across different substances.
In the table in the section below , we provide a list of substances and their respective ODP values; ODP values provide a measure of the relative destruction potential of one tonne of that substance relative to chlorofluorocarbon CFC CFC is therefore given a value of 1.
The sum of all of halogen gases in ODP tonnes provides a total measure of ozone-depleting substance emissions.
Emissions of ozone-depleting substances can be natural or man-made. Small, relatively consistent levels of ozone-depleting substances are emitted through natural processes. Most discussion in relation to ODS emissions therefore focuses on man-made emissions which can be controlled. The use of halogen gases in products such as refrigerants, solvents and foams has been persistent since the early 20th century.
These gases still reside in some products which are liable to leakage over time. Concentrations of ozone-depleting substances in the atmosphere are determined by the stock of substances, in addition to the balance of inputs and outputs over time.
The lifetime of gases in the atmosphere play an important role in understanding how their concentrations change over time. Even once emissions of ODS cease; why does the concentration of these substances not return to zero?
For many substances, this timeframe is on the scale of decades up to a century. As a result, even if emissions were halted, depleting substances which were previously emitted would continue to persist in the stratosphere. It will therefore take many decades for full recovery as substances are removed. In the table we list the range of ozone-depleting substances ODS with their corresponding ozone depleting potential ODP per tonne measured relative to CFC which is equal to 1 ; their global warming potential GWP and atmospheric lifetime in years.
The Montreal Protocol and later amendments was adopted in — since then all countries have signed on to the agreement, allowing for the dramatic decline in global ozone-depleting emissions. Ozone layer thickness declined, and the Antarctic ozone hole grew substantially from the s through to the early s. Through the first decade this trend largely stabilized and we now see initial signs of recovery.
It will take decades for the ozone layer to recover.
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