Tag Archives: ozone layer

The ozone hole over South Pole is now greater than the size of Antarctica

As every year, we celebrate today the International Day for the Preservation of the Ozone Layer, honoring the signing of the Montreal Protocol — one of our biggest environmental successes ever. But this year, in particular, is shaping up to be a bad one as scientists are warning that the hole in the ozone layer over the Southern Hemisphere is now larger than the size of Antarctica — and it’s not entirely clear why.

Vertical cross section of amount of ozone in mPa in the atmosphere in the Southern Hemisphere. The still of the animation on Sept 12th 2021 shows how the ozone hole develops from the edges to the middle, as sunlight starts chemical reactions depleting ozone. Image credit: CAMS.

The ozone depletes over the Antarctic region every year, with the hole reaching its maximum size between September and October. Following a “pretty standard” start, the hole has “considerably grown” in the last week, now larger than 75% of previous holes at this point in the season since 1979, according to recent scientific reports. 

Researchers at the Copernicus Atmosphere Monitoring Service (CAMS) monitor the developments at the ozone layer through computer modelling and satellite observations, in a similar way to weather forecasts. They’re particularly looking at the total column of ozone from measurements in the ultraviolent-visible part of the solar spectrum. 

“It wasn’t really exceptional in September, but then turned into one of the longest-lasting ozone holes in our data record later in the season. Now our forecasts show that this year´s hole has evolved into a rather larger than usual one,” Vincent-Henri Peuch, head of CAMS, said in a statement. “We are looking at a quite big and potentially also deep ozone hole.”

Last year, the ozone hole reached a peak of 24 million square kilometers in early October, which has a big larger than the previous year. This year, the hole began developing in a way that suggested it would be about the same size. But it turns out this wasn’t the case. Researchers at CAMS are now trying to figure out why this is the case.

Speaking with The Guardian, Peuch said this year’s hole is among the 25% largest in CAMS’ records but that this could change as the process is still under way. A big or small hole in one specific year doesn’t necessarily mean that the overall recovery process of the ozone layer isn’t going as expected, but it will have to be further studied, he added. 

The ozone layer

Ozone exists about 11 to 40 kilometers (seven to 25 miles) above the Earth’s surface, in the stratosphere. It’s a gaseous shield that acts like “sunscreen for the planet”, absorbing harmful ultraviolet radiation from the sun that could cause eye damage, immune suppression, and skin cancer and also damage plants and marine life. 

Image credit: CAMS.

Back in the 1970s, scientists discovered that the ozone layer thinning was being worsened by human use of halocarbons, chemical substances present in products like fridges, packaging, and aerosols. This triggered a global agreement, called the Montreal Protocol, to ban those chemicals. It was signed by virtually every country in 1987. 

According to the most recent assessment, ozone has recovered at a rate of 1-3% since 2000 in parts of the stratosphere. With the projected rates, the Northern Hemisphere and the mid-latitude ozone would fully recover by the 2030s. This is expected to be followed by the Southern Hemisphere in the 2050s and the polar regions by 2060s. 

Finally, some good environment news : the 2020 ozone layer hole closed down

In 2020 the Ozone Layer above the Antarctic was big compared to previous years, both in depth and area. Data from the Copernicus Atmospheric Monitoring Service shows the maximum occurred in October with more than 20 million square kilometers.

Every year, humans emit chemicals into the atmosphere, some of which can alter the ozone layer. But the ozone layer is pretty robust. In order for the depletion of ozone to start, temperatures in the stratosphere must be below -78°C so chemicals become active enough to destroy ozone molecules. This doesn’t always happen, but a very stable Antarctic vortex helped keep temperatures below this threshold.

Credits: NOAA

Polar vortexes are low-pressure systems, which form in the upper atmosphere. Whenever the polar Jetstream (a fast-flowing, meandering, narrow wind band) is strong, the vortex is more stable. The counterpart is a wavy polar vortex due to a weaker Jetstream. When the polar vortex is wavy, North America faces a cold winter. Australia, on the other hand, faces a wetter season.

If the polar vortex is both stable and strong, stratospheric clouds get colder, which creates the perfect conditions for the chemical reactions to start depleting the stratospheric ozone. The 2020 season had such a strong vortex. Researchers feared it could keep active for a long time and reach the maximum depletion detected. Luckily, this didn’t turn out to be the case.

It’s not the first time something like this has happened. The image below shows the comparison between previous depletion and the one from 2020. The 2020 hole’s area wasn’t as big as in 2017, but it was very stable and lasted longer. It only really started receding after mid-December.

Ozone Layer area from year to year. Credits: Coperninus ECMWF.

The lowest record of the ozone layer’s hole happened in 2019 . The entire season can be seen in the video bellow from NOAA Ozone Watch. The colors alter from blue/purple, smaller concentrations of ozone, to green/yellow, bigger concentrations.

From year to year, there may be a bigger or smaller hole, but in the end, if we wouldn’t produce the ozone-depleting chemicals, this wouldn’t be a problem in the first place. We still need to reduce emissions, and there’s no real substitute for this.

Making the average ozone hole small enough not to be so harmful is still a challenge, however. We still emit ozone-depleting chemicals, which may not be yet banned. The Montreal Protocol list needs to be continuously changed, policies concerning the environment need to be as developing as the science behind it.

This year’s ozone hole was “quite large”, says monitoring body

The ozone hole shifts in size with every year and season, but this year, it’s been the largest and deepest seen in recent times, according to scientists at the Copernicus Atmosphere Monitoring Service (CAMS).

Current readings (orange) and estimations for future (red) size of the ozone hole in 2020. Image credits CAMS.

The maximum annual size of the ozone hole above Antarctica was much bigger this year compared to recent years, hot on the heels of an “unusually small and short-lived” one in 2019, CAMS explained. This event highlights that there’s still work to be done on restoring the ozone layer and that we need to better enforce current bans on chemicals such as chlorofluorocarbons (CFCs), which are known to contribute to ozone depletion.

No ozone zone

“There is much variability in how far ozone hole events develop each year. The 2020 ozone hole resembles the one from 2018, which also was a quite large hole, and is definitely in the upper part of the pack of the last fifteen years or so”, said Vincent-Henri Peuch, director of CAMS.

The ozone layer in Earth’s upper atmosphere absorbs most of the incoming ultraviolet radiation (UV) from the sun that would otherwise be damaging to life on our planet.

Human-made chemicals, in particular refrigerant gases in the CFC family, however, have severely damaged this layer in the past. Countries all around the globe had to work together to ban such chemicals and help shield humans and wildlife from the very real danger of ozone depletion.

Despite the Montreal Protocol, which banned the production and use of CFCs, being signed in 1978, the ozone layer has not yet recovered fully. The ozone hole has become an unfortunate mainstay in the Earth’s upper atmosphere, showing yearly and seasonal variations in size. During the Arctic winter (these gases tend to concentrate at the poles), incoming force chlorine and bromine compounds into more reactive ones, which interact with ozone, depleting the layer.

CAMS explained that this year’s large rip in the layer was generated by a “strong, stable and cold polar vortex”. The polar vortex is an area of long-term low air pressures where temperatures can reach almost -80°C (-112°F); this vortex tends to remain centered around the Ross ice shelf area.

“With the sunlight returning to the South Pole in the last weeks, we saw continued ozone depletion over the area,” Peuch explains.

“After the unusually small and short-lived ozone hole in 2019, which was driven by special meteorological conditions, we are registering a rather large one again this year, which confirms that we need to continue enforcing the Montreal Protocol banning emissions of ozone-depleting chemicals.”

Ozone is considered a pollutant at ground level, and it has a pretty unpleasant smell, similar to that of chlorine-based cleaning compounds. It’s a very powerful oxidant (being an unstable molecule with 3 oxygen atoms) and will thus chemically attack living tissues in animals or plants. However, we wouldn’t be alive without it — the ozone layer blocks between 97 and 99 percent of all incoming UV light.

The largest ozone hole over the Arctic ever recorded is now plugged

The polar vortex weakened and split in two has diluted the ozone hole. Credit: Copernicus ECMWF.

This spring season, the ozone layer over the Arctic experienced a tear, which grew into the biggest ozone hole across the North Pole in recorded history. Amid tensions and gruesome daily news about the COVID-19 pandemic, it seemed like the apocalypse was nigh. Good news, though: the ozone hole was plugged nearly as fast as it appeared thanks to natural atmospheric activity.

Since it was first spotted in February, the hole in the Arctic ozone layer stretched over 620,000 square miles (1,600,000 square kilometers). No sizable hole that comes near this caliber has been reported in the Arctic since 2011.

Now, the hole has been plugged.

Researchers affiliated with the Copernicus Program, the European Union’s Earth observation program, have been on top of the situation since the ozone hole was first signaled.

This week, they announced that the “rather unusual” hole over the Arctic was not related at all to human activity and was instead caused by a strong Arctic polar vortex.

As such, the ozone layer recovery cannot be pegged to massive reductions in pollution to the coronavirus-related nationwide lockdowns.

Polar vortexes, the kind that triggered this recent massive gaping hole in the ozone layer 11 miles above the Arctic surface, are essentially large areas of low pressure and cold air that surround both of the planet’s poles.

These atmospheric phenomena wean over the summer and strengthen in the winter. Typically, polar vortexes are much weaker over the Arctic compared to the Antarctic due to local topography, as nearby land and mountain ranges disturb the flow of air more.

Ozone hole in Antarctica is a different matter entirely

At ground level, ozone or smog is a poisonous chemical often expelled by vehicle exhaust. Higher up in the stratosphere, ozone accumulates at altitudes between 10 and 50 km where it acts as a shield against the harmful ultraviolet rays, which can cause cancer. Ozone holes occur naturally from cooling, but man-made chemicals greatly accelerate their formation.

While ozone depletion over the Arctic in natural, the same can’t be said about the one in the stratosphere above Antarctica.

Almost four decades ago, scientists had learned that chlorine-containing industrial chemicals triggered the formation of a gaping hole in the ozone layer right above the icy continent.

Since then, the ozone layer has recovered after a UN emergency panel banned the use of chlorofluorocarbons (CFCs) under the Montreal Protocol. This was one of the few highly commendable episodes where nearly all the world’s countries chose to set aside their differences and work for the common good of the planet and all life that calls it home.

Currently, the ozone hole above Antarctica is the size of North America, which sounds humongous. However, it’s the smallest it’s been since 1988, according to NASA.

The ozone layer is recovering and restoring wind circulation

After decades of disruption by human activity, the ozone layer is recovering and regenerating the circulation of winds throughout the planet – a development associated with concrete measures set in place thanks to international cooperation.

Credit NASA

The ozone layer above the Earth’s surface acts as a “sunscreen” for the planet. It keeps out harmful ultraviolet radiation incoming from the sun that has been linked to skin cancer, cataracts, immune system suppression, and can also cause damage to plants.

Back in 1987, all UN-recognized countries signed the Montreal Protocol, establishing guidelines to curb the manufacture and use of agents associated with the destruction of the ozone layer, including chlorofluorocarbons — known as CFCs. The new study noted that the chemicals affecting the ozone layer also triggered a change in atmospheric circulation. However, since 2000, those changes have paused or “slightly reversed” because of the Montreal Protocol and the actions taken by countries across the globe.

“This study adds to growing evidence showing the profound effects of the Montreal Protocol,” the study’s lead author, Antara Banerjee, said in a statement. “Not only has the treaty spurred healing of the ozone layer, but it’s also driving recent changes in Southern Hemisphere air circulation patterns.”

Fast air currents, also known as jet streams, can be found swirling towards our planet’s poles at a high altitude. Before the turn of the century, ozone depletion had been driving the southern jet stream further south than usual. Now, this seems to have stopped.

Previous studies have linked the trends in circulation to weather changes. In October 2019, a study published by NASA and the National Oceanic and Atmospheric Administration said unusual weather patterns in the upper atmosphere over Antarctica caused a drastic reduction in ozone depletion.

To prove that the ozone recovery is the one driving the changes in atmospheric circulation, Banerjee and the other researchers used a technique known as detection and attribution. They determined what the changes in wind patterns were unlikely to be caused by natural changes and what could be attributed to human-related factors. The computer simulations used by the team showed that the pause or slight reversal in atmospheric circulation could only be explained by changes in the ozone layer – despite the clear expansion of carbon dioxide emissions that is driving global warming.

Nevertheless, the researchers asked to be cautious over the findings, as the trends reported could reverse themselves again. “We term this a ‘pause’ because the poleward circulation trends might resume, stay flat, or reverse,” Banerjee said in a statement.

The study was published in Nature.

Your old air-conditioning might be causing the Arctic to melt

The ozone hole shrinkage is regarded as an environmental success story for mankind. But we may have judged things too quickly: these substances have significantly contributed to global warming, particularly in the Arctic.

Here’s why that may be a good thing.

Good news

It all started in 1985 when a scientific paper reported a growing stratospheric ozone hole over Antarctica. The culprit, it soon became apparent, was coming from our household items: hairsprays, refrigerators, and air conditioners.

These items and many more were generating long-lived halogen substances that were depleting the ozone, producing a hole in the ozone layer. Remarkably, the world got together and passed legislation that banned most of these products.

It worked. After the legislation was passed, the ozone hole started shrinking more and more, recently reaching its smallest size since it was first discovered. It’s a positive story which shows that, if we get together and take swift action, we can do wonderful things and limit our environmental impact. But this isn’t the end of the story, a new study concludes.

… and bad news

Although their ozone-damaging properties were well established, these substances (eloquently called ozone-depleting substances, or ODS) have remained surprisingly understudied. Simply put, we’re not sure exactly what they do, aside from damaging the ozone layer.

Now, a new study published in Nature Climate Change reports that these substances caused about a third of all global warming from 1955 to 2005 — and about half of Arctic sea ice loss in that period. They acted as a strong supplement to carbon dioxide

“We showed that ODS have affected the Arctic climate in a substantial way,” said Lamont-Doherty researcher Michael Previdi, referring to the warming caused by these substances.

The scientists reached their conclusion using two very different climate models, both of which are widely used in the scientific community, and both of which were developed at the U.S. National Center for Atmospheric Research.

This means that the Montreal Protocol, the international treaty designed to protect the ozone layer by phasing out the production of ODS, is even more important than we thought — not only was it protecting the ozone layer, but it was also fighting climate change without us even realizing it.

Which leads us to why this may all be a good thing.

… and good news again

Because we’ve already banned these substances, their effect is starting to fade, and they’ve already started to dissipate in the decades since the ban. This means that, unwittingly, we’ve taken an important step to combat climate change.

“Our findings also have implications for the future because the phase-out of [ozone-depleting substances], which is well under way, will substantially mitigate Arctic warming and sea-ice melting in the coming decades,” the study explains.

It’s heartening to see that what appeared to be bad news actually turned out to be a positive story.

“Climate mitigation is in action as we speak because these substances are decreasing in the atmosphere, thanks to the Montreal Protocol,” said Lorenzo Polvani, lead author of the study and a professor in Columbia’s Department of Applied Physics and Applied Mathematics. “In the coming decades, they will contribute less and less to global warming. It’s a good-news story.”

However, we mustn’t be too hasty to pat ourselves on the back. Although these results look promising, they still need to be confirmed by additional study. In addition, despite bans and reductions, there is still a healthy amount of ODS being produced and expelled into the atmosphere. Their replacements can also spell bad news and have the potential to trap atmospheric heat.

To avoid ending on a bad note, this can be good news nonetheless. But it also shows just how much of an impact our decisions can have — both positive and negative.

Earth’s thin atmosphere is all that stands between life on Earth and the cold, dark void of space. Our planet's atmosphere has no clearly defined upper boundary but gradually thins out into space. The layers of the atmosphere have different characteristics, such as protective ozone in the stratosphere, and weather in the lowermost layer. Credit: NASA.

Hole in ozone layer should completely patch up within 50 years, UN says

After a string of depressing news about the climate and the environment, there’s finally something to be happy about. According to a new United Nations report, the hole in the ozone layer should completely heal within our lifetimes — a testament to the fact that concentrated international action really does work.

Earth’s thin atmosphere is all that stands between life on Earth and the cold, dark void of space. Our planet's atmosphere has no clearly defined upper boundary but gradually thins out into space. The layers of the atmosphere have different characteristics, such as protective ozone in the stratosphere, and weather in the lowermost layer. Credit: NASA.

Earth’s thin atmosphere is all that stands between life on Earth and the cold, dark void of space. Our planet’s atmosphere has no clearly defined upper boundary but gradually thins out into space. The layers of the atmosphere have different characteristics, such as protective ozone in the stratosphere, and weather in the lowermost layer. Credit: NASA.

At ground level, ozone or smog is a poisonous chemical often expelled by vehicle exhaust. Higher up in the stratosphere, ozone accumulates at altitudes between 10 and 50 km where it acts as a shield against the harmful ultraviolet rays, which can cause cancer. Ozone holes occur naturally from cooling, but man-made chemicals greatly accelerate their formation. Chlorine, in particular, is very harmful since these atoms are extremely reactive with ozone. Currently, the ozone hole above Antarctica is the size of North America, which sounds humongous. However, it’s the smallest it’s been since 1988, according to NASA.

Almost 30 years ago, a UN emergency panel banned the use of chlorofluorocarbons (CFCs) under the Montreal Protocol. Scientists had learned that these chlorine-containing chemicals triggered the formation of a gaping hole in the ozone layer right above Antartica. Since then, the ozone layer has clearly recovered, marking a great success — one of the few but highly commendable episodes where nearly all the world’s countries chose to set aside their differences and work for the common good of the planet and all life that call it home.

In January 2018, researchers at NASA reported the first direct evidence that the ozone hole is recovering. They studied microwaves emissions that can identify and count trace gases even during the dark southern winter. According to the NASA researchers’ results, the ban on CFCs has resulted in about 20 percent less  during the Antarctic winter compared to 2005. On average, chlorine levels are declining by about 0.8 percent annually, the authors reported in the Geophysical Research Letters. 

The hole in the ozone layer is getting smaller and smaller. Credit: ECMWF.

The hole in the ozone layer is getting smaller and smaller. Credit: ECMWF.

Now, the latest report put out by a UN panel suggests that the ozone hole could patch up in the 2060s, if all goes to plan. The report has been released every four years since the Montreal Protocol was instated.

Some regions are recovering faster than others. Above the Arctic and mid-latitudes of the northern hemisphere, the ozone layer could return to normal levels by 2030s, while mid-latitudes in the southern hemisphere could reach pre-ozone depletion levels by mid-century.

“The Montreal Protocol is one of the most successful multilateral agreements in history for a reason,” said Erik Solheim, head of UN Environment.

“The careful mix of authoritative science and collaborative action that has defined the Protocol for more than 30 years and was set to heal our ozone layer is precisely why the Kigali Amendment holds such promise for climate action in future.”

The challenge will lie in keeping up this momentum. Though CFCs have been banned, there are other chemicals that contribute to the Antarctic ozone hole. Ironically, one chemical called dichloromethane, which has been officially deemed as a replacement for CFCs following the Montreal Protocol, can deplete the stratospheric shield. These chemicals usually break down in less than six months, but simulations show that dichloromethane and other so-called ‘very short-lived substances’ (VSLS) account for a significant portion of ozone loss in the stratosphere.

Over the past decade, dichloromethane became approximately 60% more abundant in the atmosphere as compared to the early 2000s. Besides dichloromethane, another highly concentrated chemical identified in the stratosphere includes 1,2-dichloroethane — an ozone-depleting substance used to make PVC, a popular construction material. PVC manufacturing has surged in the last couple of years in China, its main hotspot. There are also some places where the CFC ban is not enforced (again, China).

Another powerful class of ozone-depleting chemicals called hydrofluorocarbons (HFCs) is also worrisome. However, in response to the rapid growth of HFC emissions, the 197 parties to the Montreal Protocol adopted the Kigali Amendment in 2016 to reduce gradually their global production and consumption. HFCs, used mainly in refrigeration, air conditioning, and heat pump equipment, are thousands of times more harmful to the climate than CO2. Global implementation of the Kigali Amendment, which should enter into force on 1 January 2019, would prevent up to 80 billion tonnes CO2 equivalent of emissions by 2050, or the equivalent of 0.4% of global warming, by the end of the century.

“These new assessment results highlight the importance of continued long-term monitoring of HFCs in the atmosphere as the Kigali Amendment begins to take hold,” said David Fahey, Co-Chair of the Montreal Protocol Scientific Assessment Panel and scientist at the NOAA Earth System Research Laboratory in the US.

“Carbon dioxide emissions remain by far the most important greenhouse gases which are driving global warming. But we can also help tackle climate change by reducing our commitment to other gases including HFCs. Every bit of warming matters,” said World Meteorological Organization Secretary-General Petteri Taalas.

Ozone Hole.

Ozone hole at its slimmest after 30 years of international effort, keeps shrinking

The hole in our planet’s ozone layer is getting patched up. At its peak this year, the hole grew to be two and a half times the size of the US territory, its smallest proportions since 1988 according to NASA.

Ozone Hole.

It’s blue, it’s menacing, it’s a bit tinier than last year! Hurrah for progress!
Image via NASA / Ozone Hole Watch.

Spreading up to 7,6 million square miles (19.69 million km2) at its peak this year on September 11, the hole in our atmosphere’s ozone layer seems to be healing. The hole, currently looming above Antarctica, was 1.3 million square miles (3.36 million km2) smaller than last year, the smallest it’s ever been since 1988, and it keeps shrinking.

Atmospheric sunscreen

Ozone, sometimes called trioxygen, is an allotrope (a particular structural layout) of oxygen. It’s a molecule made up of three oxygen atoms, O3, and is less chemically stable than the regular O2 molecule. Ozone is a pale-blue, toxic and quite smelly gas, but that’s ok since it breaks down into regular oxygen in the lower atmosphere. It’s also a relatively rare gas, generally formed in the upper atmosphere under the action of UV rays and the charges they generate in the lower layers of the stratosphere.

Because chemistry has a sense of humor, that same ozone layer absorbs virtually all (98% to 99%) of incoming, medium-frequency UV radiation. Awesome news if you like being alive or at least not in constant agony from radiation burns, since UV radiation can wreak havoc on organisms living on land. Exposure to higher levels of UV radiation (such as those associated with a thinned ozone layer) significantly raise the risks of developing cataract and skin cancer. Wide-scale exposure to UV levels expected in the absence of the ozone layer would drastically impact whole ecosystems at a time, and would significantly change the shape of life on Earth as we today know it.

Heavy use of ozone-damaging chemicals — in particular, clorofluorocarbons and hydrochlorofluorocarbons (CHCs and HCHCs) used in old-timey fridges and spray cans — burned a gaping hole in this layer in the 70’s and 80’s. These substances break apart in the upper atmosphere, freeing chlorine and bromine to bind with the ozone. The reactions are quicker over Antarctica (where the hole currently looms) as the frozen polar stratospheric clouds offer surfaces upon which heterogeneous chemical reactions take place.

The hole understandably had everyone quite panicked. But it’s starting to show signs of healing up.

NASA researchers believe that the increasing temperatures we’ve seen in later years helped plug the hole, as warmer bodies of air in the stratosphere help limit the rise of damaging chemicals, such as chlorine and bromine, to the ozone layer.

“The Antarctic ozone hole was exceptionally weak this year,” Paul Newman, chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. “This is what we would expect to see given the weather conditions in the Antarctic stratosphere.”

This effect, however, is like the jiggling of the gas indicator while your car is running — quite tiny, and quite chaotic. The lion’s share of the progress, the draining of the gas from your car’s tank in our metaphor, can be tracked down to the year 1987 when the evidence of ozone degradation grew so worrying authorities implemented the Montreal Protocol on Substances that Deplete the Ozone Layer. Over time, the protocol grew to be an international agreement which drove massive efforts, all throughout the world, to phase out most ozone-depleting chemicals.

Almost like international agreements on threatening environmental issues are a good thing in the long run and probably shouldn’t be abandoned, right?

Paris agreement.

Hint, hint, wink, wink, America.
Seen in April at the March for Science, Washington DC. Image credits Becker1999 / Wikimedia.

The good news marks the 30th anniversary of the ozone hole’s discovery. NASA further reports that the ozone hole was at its widest in the year 2000, at 11.5 million square miles (29.78 million km2) and will likely need a further 50 years to return to its 1980s size.

Overall, very encouraging news, but one that goes to show the huge inertia Earth’s systems have in relation to change. A lesson we should take to heart as we try to grapple climate change.

ozone-layer-chemicasl

Four newly discovered man-made gases destroy the ozone layer

ozone-layer-chemicasl

It was only around the mid 1980s that the world finally recognized the dangers posed by the build-up of chlorofluorocarbons (CFCs) in the atmosphere. A big hole in the ozone layer revealed at the time by a team of scientists from the British Antarctic Survey showed what these sort of chemicals withering through the atmosphere could do. Luckily, CFCs have become regularized since then, yet apparently there are still other chemicals being funneled into the atmosphere.  University of East Anglia report in recent study that they have identified four new gases that destroy ozone – the sources of these gases have yet to be discovered.

Sitting between 15 and 30 km from the Earth’s surface, the ozone layer is paramount to life on Earth as it filters the sun’s dangerous ultraviolet rays. The Montreal Protocol that came into effect on 1987 limited the release of CFCs, substances that were once widely used in refrigeration and as aerosol propellants in products like hairsprays and deodorants. It wasn’t until 2010 that a global ban on production altogether was enforced.

Now, the University of East Anglia researchers report the discovery of four new gases with destructive capabilities against the ozone. Three of these are also CFCs and one is a hydrochlorofluorocarbon (HCFC), which can also damage ozone. The findings came after polar firn ( perennial snow pack) in addition to modern air signatures  were analyzed. This snow is like a sort of natural archive which can tell scientists how air quality looked like up to 100 years ago.

The data suggests that these four gases weren’t present in the atmosphere at all until the 1960s and  that about 74,000 tonnes of these gases have been released into the atmosphere. Two of the gases are still accumulating at high rates, suggesting that whatever the source may be it’s still at it.

“The identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer,” said lead researcher Dr Johannes Laube.

“We don’t know where the new gases are being emitted from and this should be investigated. Possible sources include feedstock chemicals for insecticide production and solvents for cleaning electronic components.”

“What’s more, the three CFCs are being destroyed very slowly in the atmosphere – so even if emissions were to stop immediately, they will still be around for many decades to come,” he added.

Of course, the concentration of any of these gases,  CFC-113a being the most powerful emission of the four, is far from being alarming, yet it’s imperative that the exact sources of these ozone destroyers be found in order for prevention efforts to come into effect. In other related news, I wrote earlier about another recently discovered man-made gas, this time a greenhouse gas, called perfluorotributylamine, or PFTBA, which is 7,100 times worse than CO2.

Findings were reported in a paper published in the journal Nature Geoscience.

NASA reveals new information on ozone hole – no good news in sight

NASA scientists have revealed new data on the ozone hole that forms each year above Antarctica and found that the decrease of chlorine in the atmosphere hasn’t had any significant positive impact. Chlorine is the most dangerous substance for the ozone layer.

Image Credit: NASA/Ozone Hole Watch

Image Credit: NASA/Ozone Hole Watch

20 years ago, the Montreal Protocol was installed. The Montreal Protocol on Substances that Deplete the Ozone Layer is an international treaty designed to protect the ozone layer and reduce or even eliminate the production of substances which cause damage to the ozone layer. However, two new studies show that despite an apparent reduction in the quantity of chlorine and other such substances, two new studies show that signs of recovery are not yet present.

“Ozone holes with smaller areas and a larger total amount of ozone are not necessarily evidence of recovery attributable to the expected chlorine decline,” said Susan Strahan of NASA’s Goddard Space Flight Center in Greenbelt, Md. “That assumption is like trying to understand what’s wrong with your car’s engine without lifting the hood.”

In order to gather this information, they used satellites to peek through the ozone hole. Strahan and Natalya Kramarova, also of NASA Goddard, turned to data from the NASA-NOAA Suomi National Polar-orbiting Partnership satellite and used the satellite’s Ozone Mapper and Profiler Suite’s Limb Profiler to create a map that shows how the amount of ozone varied with altitude throughout the stratosphere during the 2012 season.

The map revealed not only that the hole isn’t shrinking, but that it is much more complex than previously thought.

“Our work shows that the classic metrics based on the total ozone values have limitations – they don’t tell us the whole story,” Kramarova said.

image_2_0

A look inside the 2012 ozone hole with the Ozone Mapper and Profiler Suite shows how the build-up of ozone (parts per million by volume) in the middle stratosphere masks the ozone loss in the lower stratosphere.
Image Credit: NASA

Basically, classic metrics show that the hole has improved since the Montreal protocol. But in reality, weather parameters (winds, most notably) are responsible for the increased ozone and resulting smaller hole. This is what this study has shown: that winds can have a significant impact on the ozone hole and apparent improvements were only apparent weather-caused changes.

The only good thing is that chlorine emissions have been going down; at a pretty slow pace, but they’ve been going down. However, until chlorine levels in the lower stratosphere decline below the early 1990s level (which is something expected to happen anywhere between 2015-2030) temperature and winds will continue to dictate the variable area of the hole in any given year.

“We are still in the period where small changes in chlorine do not affect the area of the ozone hole, which is why it’s too soon to say the ozone hole is recovering,” Strahan said. “We’re going into a period of large variability and there will be bumps in the road before we can identify a clear recovery.”

Antarctic ozone hole shows big improvement – not all good

The hole in the ozone layer is the second smallest in twenty years, data from NASA and NOAA shows, but it’s not all good news. In fact, it could signal things taking a turn for the worst.

Warmer air temperatures high above the Antarctic led to the hole shrinking, now covering an area of about 17.9 million square kilometers. The ozone layer protects all life on Earth, filtering 97–99% of the Sun’s harmful medium-frequency ultraviolet light. The ozone density also seems to be growing higher and higher, which is also caused by the warming of the area; if this is indeed the case, this improvement won’t last and things will get worse in the near future.

“The ozone hole mainly is caused by chlorine from human-produced chemicals, and these chlorine levels are still sizable in the Antarctic stratosphere,” says NASA atmospheric scientist Paul Newman. Natural fluctuations in weather patterns resulted in warmer stratospheric temperatures this year. These temperatures led to a smaller ozone hole.”

The hole in the ozone layer was first observed in the early 1980s, and it was caused by chlorine emissions created by human activity; chlorine can break down ozone molecules very quickly.

“It happened to be a bit warmer this year high in the atmosphere above Antarctica, and that meant we didn’t see quite as much ozone depletion as we saw last year, when it was colder,” said Jim Butler with NOAA’s Earth System Research Laboratory in Boulder, Colo.

When the ozone layer hit its maximum, it was bigger than the US, Canada and Mexico combined.

Via NOAA

Gamma-ray burst illustration. (c) NASA

Gamma-ray bursts might cause mass extinction on Earth

Gamma-ray burst illustration. (c) NASA

Gamma-ray burst illustration. (c) NASA

Most of us tend to believe the Earth is a safe heaven, with little regard to outerwordly consequences. The truth is our planet, although without a doubt a true gem within our galaxy, is susceptible to a slew of events triggered from within or well beyond our solar system. A lot of them are very dangerous to life on Earth, be it a menacing asteroid, a solar flare or even a terrifying gamma-ray burst.

Researchers of Washburn University, in Topeka, Kan. have studied gamma-ray bursts and its potential consequences, and now claim the Earth quite probably has been met by such events during its history, with dramatic consequences on the life harbored within it.

Gamma-ray bursts typically occur  when two stars collide, a process which leads to a giant energy burst into outer space. The gamma-ray bursts have the capability of depleting stratospheric ozone, allowing the most powerful and damaging forms of ultraviolet radiation to reach the Earth’s surface. Researchers are now beginning to connect the timing of these gamma-ray bursts to extinctions on Earth that can be dated through the fossil record.

“We find that a kind of gamma-ray burst — a short gamma-ray burst — is probably more significant than a longer gamma-ray burst,” study researcher Brian Thomas of Washburn University, in Topeka, Kan., said in a statement. “The duration is not as important as the amount of radiation.”

There are two types of gamma-ray bursts:  a longer, brighter burst caused by two collinding stars, as discussed earlier, and a short timed burst. The later caused by the collision of two black holes or neutron stars are even more harmful bursting an outrageous amount of radiation, even though the event only lasts a second.

Such an event, the researchers say, happens about once per 100 million years in any given galaxy. But if one did happen here, the results would be devastating. According to the scientists treating the study, if such an event should occur inside the Milky Way, dire consequences might afflict the Earth. The radiation, after reaching the atmosphere, would caused the depletion of the ozone by  knocking free oxygen and nitrogen atoms so they can recombine into ozone-destroying nitrous oxides. Earth would have been hit by several of these short-hard events over the course of its 4.5-billion-year history, according to the study authors.

The researchers are now looking of evidence of such an event. If a gamma-ray burst would have hit the Earth, the best sign of this would be the discovery of isotope iron-60. Isotopes like these   can reveal the strata of the events, it then becomes a matter of looking for extinction events that correlate and examining which species died and which survived.

“I work with some paleontologists and we try to look for correlations with extinctions, but they are skeptical,” said Thomas. “So if you go and give a talk to paleontologists, they are not quite into it. But to astrophysicists, it seems pretty plausible.”

 

Venus Express has two solar cell panels per wing comprising alternating rows of standard triple junction solar cells as well as highly reflective mirrors to reduce the operating temperatures. (c) ESA

Ozone layer found on Venus

Venus Express has two solar cell panels per wing comprising alternating rows of standard triple junction solar cells as well as highly reflective mirrors to reduce the operating temperatures. (c) ESA

Venus Express has two solar cell panels per wing comprising alternating rows of standard triple junction solar cells as well as highly reflective mirrors to reduce the operating temperatures. (c) ESA

ESA’s Venus Express spacecraft has found an ozone layer high in the atmosphere of Venus, similar to that surrounding Earth and Mars according to astronomers. Ozone is considered fundumental to providing an environment capable of supporting life, as it absorbs much of the sun’s harmful ultraviolet ray. This recent discovery will provide highly valuable insight as to how life formed on our planet, as well as more refined parameters for scientists’ hunt for extraterestial life.

The study was recently presented at the Joint Meeting of the European Planetary Science Congress and the American Astronomical Society’s Division for Planetary Sciences. Franck Montmessin from the Laboratoire Atmospheres, Milieux, Observations Spatiales (LATMOS) in Guyancourt, France, led the team who carried out this study.

“This detection gives us an important constraint on understanding the chemistry of Venus’ atmosphere,” Franck Montmessin, who led the research, said in a press release.

The find was made with the help of SPICAV, an instrument aboard Venus Express, which analyzed the starlight around the planet and found characteristic fingerprints of gases in the atmosphere as they absorbed light. Ozone was detectable because it absorbed some of the ultraviolet from the starlight

Previous to this discovery, ozone has been observed on Earth and Mars only. The build-up of oxygen, and consequently ozone, in Earth’s atmosphere began 2.4 billion years ago. Scientists believe the ozone formed as a result of ancient microbes excreting oxygen as a waste gas, along with primitive plant life, which to this day are the main source of replenishing ozone. Greenhouse emissions gathered in the atmosphere in more than 100 years has taken its significant toll on Earth’s ozone along the years. It wouldn’t be too hard for Earth to become a second Venus in the future.

Venus’ ozone layer sits at an altitude of about 62 miles, which is about four times higher in the atmosphere than Earth’s.  ESA said astrobiologists believe that a planet’s ozone concentration must be 20 percent of Earth’s value before life should be considered as a cause of it. Common sense would dictate that on a planet where acid rains and furnace hot surface temperatures dictate, any talk of signs of life would sound trivial, but bacteria and other sorts of micro organisms can find their niche even in the harshest of environments – even on a hellish planet like Venus.

“We can use these new observations to test and refine the scenarios for the detection of life on other worlds,” says Franck Montmessin, who led the research.

 

Dramatic never before seen depletion of ozone layer in the Arctic region

The ozone layer in the arctic regions has suffered unprecedented damage this winter due to cold weather in the upper atmosphere. By the end of March 40% of the ozone in the stratosphere had been destroyed, compared to the previous record of 30%.

The European Space Agency, the UN World Meteorological Organization (WMO) as well as the Alfred Wegener Institute for Polar and Marine Research have all been monitoring the situation in the arctic regions, and all of them have confirmed the dramatic depletion.

According to the WMO, “depletion of the ozone layer … has reached an unprecedented level over the Arctic this spring because of the continuing presence of ozone-depleting substances…”

The European Space Agency also notes that “Envisat satellite has measured record low levels of ozone over the Euro-Atlantic sector of the northern hemisphere during March.”

The ozone layer may be the ultimate protection against harmful radiation, but it is also extremely vulnerable to chemical substances. The dramatic loss is caused by surprisingly strong winds known as the polar vortex, which secluded the atmospheric mass over the North Pole. To put it in blunt terms, things are bad, and they will get worse.

“Our measurements show that at the relevant altitudes about half of the ozone that was present above the Arctic has been destroyed over the past weeks,” Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) researcher Markus Rex said in early March. “Since the conditions leading to this unusually rapid ozone depletion continue to prevail, we expect further depletiofn to occur.”