The Arctic Is a Staggering 36 Degrees Hotter Than What It Should Be


In Brief
  • Temperatures in the Arctic are reaching 20 °C (36 °F) higher than normal above 80 degrees North Latitude.
  • Experts assert that the warmth is a result of a combination of record-low sea-ice and warm/moist air from lower latitudes being driven northward by a jet stream.

Arctic Warmth

Something strange is going on in the Arctic circle right now. Because it’s Polar Night, the region has been experiencing days with no sun. Common sense would dictate that a lack of sun would result in colder temperatures. However, this isn’t what’s happening.

According to Arctic watchers, the region is experiencing temperatures higher than usual, and the amount of sea ice covering the polar ocean is at a record low. Zack Labe, a PhD student at the University of California at Irvine who studies the Arctic, tweeted an image showing that temperatures in the Arctic are reaching 20 °C (36 °F) higher than normal above 80 degrees North Latitude.

The image in the tweet shows that temperatures were around -5 degrees Celsius instead of the typical -25 degrees Celsius.

Changing Seas and Winds

Experts are weighing in on the temperature spike.

Mark Serreze, from the National Snow and Ice Data Center in Boulder, Colorado found unusual temperatures in the sea. “There are some areas in the Arctic Ocean that are as much as 25 degrees Fahrenheit above average now.” This situation leads to less sea-ice forming this time of the year, as measured by the National Oceanic and Atmospheric Administration which is just 6.39 million km(2.47 million mi2), 28.52 percent less than the 1981-2010 average.

Credit: NOAA

Jennifer Francis, an Arctic specialist at Rutgers University said in a statement for The Washington Post:

“The Arctic warmth is the result of a combination of record-low sea-ice extent for this time of year, probably very thin ice, and plenty of warm/moist air from lower latitudes being driven northward by a very wavy jet stream.”

Francis published a study in 2015 that shows how jet stream patterns are slowly shifting northward to the Arctic, leading to the warming of the region. “As emissions of greenhouse gases continue unabated, therefore, the continued amplification of Arctic warming should favor an increased occurrence of extreme events caused by prolonged weather conditions,” the paper states.

These record-low sea levels and temperature spikes will surely add to the mounting evidence for climate change. There’s no denying it anymore.

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Global warming proponents and sceptics agree on one point: study into myth of ‘pause’ merits more research


A study suggesting that the “pause” in global warming is not real has managed to unify climate scientists and their arch-sceptics over the need for further research to clarify whether global average temperatures really have flat-lined over the past 15 years.

The study, by Kevin Cowtan of York University and Robert Way of Ottawa University, found that the global warming pause could be virtually eliminated by including temperature estimates from the Arctic, which are currently excluded because of a lack of weather stations in this remote region.As revealed today by The Independent, the study used an established statistical technique called kriging to fill in the missing surface temperatures in the Arctic with satellite readings of the atmosphere above. This eliminated the pause or hiatus in global average temperatures that appears to have developed over the past decade or more.The slowdown in temperatures has been used by climate sceptics, such as the former Chancellor Lord Lawson of Blaby, to undermine the science of climate change, claiming that global warming has stopped despite a continuing rise in industrial emissions of greenhouse gases – set to reach a record 36 billion tons in 2013.However, Lord Lawson said yesterday that he would like to read the latest study before commenting on it in detail. “These things come out from time to time and sometimes they have merit and sometimes they don’t. It needs to be reviewed by other scientists,” Lord Lawson told The Independent.However, the science writer and climate sceptic Matt Ridley, now Lord Ridley, a Conservative hereditary peer, dismissed the latest study because it relies on swapping one type of “uncertain data” used to fill in the gaps in the polar region with another.”Even if that gives a slight net warming for the past 15 to 17 years, it does not change the fact that the warming over the full 34 years since warming began has been slower than predicted by 95 per cent of the [computer] model runs consulted by the Intergovernmental Panel on Climate Change….The key point is that warming is slower than expected,” Lord Ridley said.

Rasmus Benestad of the Norwegian Meteorological Institute in Oslo, who was one of the first scientists to try to estimate the effect of the missing Arctic warming data on global average temperatures, said that the latest study is a useful contribution to the debate.

“The pronounced recent warming can be inferred from different and independent observations, such as the melting of the ice on Greenland, thawing of permafrost, and the reduction of the sea-ice. Hence, when the most rapidly warming regions on Earth are not part of the statistics, the global mean estimate is bound to be lower than the real global mean. Hence, our picture of Earth’s surface temperature is somewhat ‘patchy’,” Dr Benestad said.

It is likely that the slowdown in global average temperatures to the Earth’s surface is the result of a combination of factors, such as the uptake of heat in the deep oceans, the effect of El Nino and La Nina conditions in the Pacific Ocean, in addition to the hidden temperature increases in the Arctic, he said.

Professor Richard Allan of the University of Reading said that the study by Cowtan and Way appears reasonable as they have tested their method by applying the technique to regions of the world where there are ground-based measurements to gauge its accuracy. However, the study is still preliminary and will need to be scrutinised by other scientists, Professor Allan said.

“There is still a slowdown in the rate of global average surface warming in the 21st century compared to the late 20th century and this still looks to be caused by natural fluctuations in the ocean and other natural climate fluctuations relating to volcanic eruptions and changes in the brightness of the sun,” Professor Allan said.

“However, the size of this slowdown and the discrepancy between observations and climate simulations may be less than previously thought.  The conclusions of the IPCC stands: we can expect a return to substantial warming of the planet over the coming decades in response to rising concentrations of greenhouse gases,” he said.

Ed Hawkins of Reading University added: “This is an interesting and important contribution to the continuing discussion about the recent temperature hiatus, but is unlikely to be the final word on the issue. It must also be remembered that a 15-year trend is still too short to be considered as representative of longer-term global temperature trends, and also too short to be meaningfully compared with climate simulations.”

The Conservative MP Peter Lilley said that he is not convinced that the latest study can explain the pause. “The IPCC tried to explain the pause by saying the heat is in the deep ocean and now these people say it’s in the polar regions. They both can’t be right,” Mr Lilley said.

Global Warming Puts the Arctic on Thin Ice.


arctic

Answers to questions about the Arctic’s shrinking ice cap and its global significance.

1.    Why are global warming specialists watching the Arctic so closely?

2.    What kinds of changes are taking place in the Arctic now?

3.    How does this dramatic ice melt affect the Arctic?

4.    Will Arctic ice melt have any effects beyond the polar region?

5.    Can we do anything to stop global warming?

 

1. Why are global warming specialists watching the Arctic so closely?

The Arctic is global warming’s canary in the coal mine. It’s a highly sensitive region, and it’s being profoundly affected by the changing climate. Most scientists view what’s happening now in the Arctic as a harbinger of things to come.

Since 1979, the size of the summer polar ice cap has shrunk more than 20 percent.

2. What kinds of changes are taking place in the Arctic now?

Average temperatures in the Arctic region are rising twice as fast as they are elsewhere in the world. Arctic ice is getting thinner, melting and rupturing. For example, the largest single block of ice in the Arctic, the Ward Hunt Ice Shelf, had been around for 3,000 years before it started cracking in 2000. Within two years it had split all the way through and is now breaking into pieces.

The polar ice cap as a whole is shrinking. Images from NASA satellites show that the area of permanent ice cover is contracting at a rate of 9 percent each decade. If this trend continues, summers in the Arctic could become ice-free by the end of the century.

3. How does this dramatic ice melt affect the Arctic?

The melting of once-permanent ice is already affecting native people, wildlife and plants. When the Ward Hunt Ice Shelf splintered, the rare freshwater lake it enclosed, along with its unique ecosystem, drained into the ocean. Polar bears, whales, walrus and seals are changing their feeding and migration patterns, making it harder for native people to hunt them. And along Arctic coastlines, entire villages will be uprooted because they’re in danger of being swamped. The native people of the Arctic view global warming as a threat to their cultural identity and their very survival.

4. Will Arctic ice melt have any effects beyond the polar region?

Yes — the contraction of the Arctic ice cap is accelerating global warming. Snow and ice usually form a protective, cooling layer over the Arctic. When that covering melts, the earth absorbs more sunlight and gets hotter. And the latest scientific data confirm the far-reaching effects of climbing global temperatures.

Rising temperatures are already affecting Alaska, where the spruce bark beetle is breeding faster in the warmer weather. These pests now sneak in an extra generation each year. From 1993 to 2003, they chewed up 3.4 million acres of Alaskan forest.

Melting glaciers and land-based ice sheets also contribute to rising sea levels, threatening low-lying areas around the globe with beach erosion, coastal flooding, and contamination of freshwater supplies. (Sea level is not affected when floating sea ice melts.) At particular risk are island nations like the Maldives; over half of that nation’s populated islands lie less than 6 feet above sea level. Even major cities like Shanghai and Lagos would face similar problems, as they also lie just six feet above present water levels.

Rising seas would severely impact the United States as well. Scientists project as much as a 3-foot sea-level rise by 2100. According to a 2001 U.S. Environmental Protection Agency study, this increase would inundate some 22,400 square miles of land along the Atlantic and Gulf coasts of the United States, primarily in Louisiana, Texas, Florida and North Carolina.

A warmer Arctic will also affect weather patterns and thus food production around the world. Wheat farming in Kansas, for example, would be profoundly affected by the loss of ice cover in the Arctic. According to a NASA Goddard Institute of Space Studies computer model, Kansas would be 4 degrees warmer in the winter without Arctic ice, which normally creates cold air masses that frequently slide southward into the United States. Warmer winters are bad news for wheat farmers, who need freezing temperatures to grow winter wheat. And in summer, warmer days would rob Kansas soil of 10 percent of its moisture, drying out valuable cropland.

5. Can we do anything to stop global warming?

Polar Action Guide

Yes. When we burn fossil fuels — oil, coal and gas — to generate electricity and power our vehicles, we produce the heat-trapping gases that cause global warming. The more we burn, the faster churns the engine of global climate change. Thus the most important thing we can do is save energy.

And we can do it. Technologies exist today to make cars that run cleaner and burn less gas, generate electricity from wind and sun, modernize power plants, and build refrigerators, air conditioners and whole buildings that use less power. As individuals, each of us can take steps to save energy and fight global warming.

Source: NGC

 

 

Melting Arctic Ice Will Make Way for More Ships–and More Species Invasions.


 

melting-arctic-sea-ice-means-more-shipping-and-more-invasive-species_1

A new study shows immense increases in shipping are likely over the North Pole and Arctic Ocean in the coming years, alerting scientists who study invasive species

The rare ships that have ventured through the harsh, icebound Arctic Ocean require reinforced hulls and ice-breaking bows that allow them to plow through dense ice as much as two meters deep, and face hazardous conditions in remote locations for long periods of time. Arctic sea ice now is melting so rapidly each summer due to global warming, however, that ships without ice-breaking hulls will be able to cross previously inaccessible parts of the Arctic Ocean by 2050. And light-weight ships equipped to cut through one meter of ice will be able to travel over the North Pole regularly in late summer, according to a new study published March 4 in Proceedings of the National Academy of Sciences Plus.

That’s good news for economic development because it offers many new and faster routes from east to west, shaving 40 percent off transportation time and fuel costs compared with shipments via the Suez Canal. But the geographic extent of trade routes across the Arctic is worrisome for scientists who study invasive species.

Ships traveling regularly in the Northwest Passage, beyond the Northern Sea Route and through the central Arctic Ocean, will likely bring new invaders to the Arctic as well as to northern ports. Mosquitoes and forest beetles are expected to survive hidden in cargo, for example. Hearty marine organisms, such as mussels and barnacles, will likely tag along as larvae in ballast tanks or in niche areas on vessel hulls. When new species flourish in a new environment they can become harmful, damaging local ecosystems and threatening native plants and animals, much as the Japanese vine known as kudzu has overrun the southern U.S. Economic costs associated with new pests have been significant—for example, the influx of zebra mussels into the Great Lakes has been estimated at $1 billion annually.

“The temptation for many new ships to enter [the Arctic] will be huge,” says University of California, Los Angeles, geographer Laurence Smith, lead author of the new study. Arctic shipping already has grown by leaps and bounds in just the past few years. In 2012, which set a record for lowest sea ice extent, a total of 46 ships—the most ever—traversed the Arctic Ocean. Thirty-four ships made the passage in 2011 whereas just four had done so the year before. For context, 19,000 ships pass through the Suez Canal annually.

Sea ice has long been a barrier to shipping across the Arctic Ocean as well as to species. Already, shipping is by far the most common pathway for marine invasive species, responsible for 69 percent of species introductions to marine areas, followed by aquaculture at 41 percent (non-native species can have more than one pathway of introduction, meaning some double counting.) The most common transport method is ships’ ballast water. Organisms can also hitch a ride in nooks and crannies on a ship’s hull, known as hull fouling. And organisms such as forest pests and mosquitoes can survive long trips in pallets and in cargo such as tires.

Invasive species are one of those things that once the genie is out of the bottle, it’s hard to put her back in,” says climate scientist Jessica Hellmann of the University of Notre Dame who was not involved with this study. Hellmann studies the impact of climate change on invasive species and ecological systems. As Arctic ice melts, new ports will be connected and shorter passages between existing ports will lead to new opportunities for invasive species to spread, she says.

Cold storage
Mario Tamburri, a marine scientist and director of the Maritime Environment Resource Center at the University of Maryland Center for Environmental Science, has been researching survivorship and reproduction of organisms likely to be transported by ships by mimicking the conditions of shipping traffic. New colder, shorter routes afforded by the retreat of ice help invaders, such as mussels, barnacles and crabs, on a biological level, Tamburri says. Cold water slows metabolism of organisms, which can sustain themselves in low food conditions. “It’s like putting your groceries on ice,” he says.

Shorter routes also mean more organisms either attached to the hull or in ballast water are now more likely to survive the journey. Previously, the high heat and lack of light of longer trips outside the Arctic killed them off. “When ships now transport goods through the Panama Canal, for instance, through warm water and freshwater, natural barriers to invasive species are built into the shipping routes,” Tamburri says. “In the Arctic, those barriers go away.”

Ballast water and bivalves
Murmansk, Russia, a leading global port and the largest city north of the Arctic Circle, is one area that ice-free routes will likely open up further this summer. As more ships exchange ballast water for cargo, native species in places like Murmansk can quickly lose out against new species that have no checks and balances, such as marine species like bivalves that can be dispersed by larvae in ballast water as well as cold-water adapted adults, including green crabs.

Lewis Ziska, a plant physiologist with the U.S. Department of Agriculture’s Agricultural Research Service, says that once introduced, a new species can outcompete everything that has evolved over millennia. Although some nonnative species are innocuous, others thrive because there have no predators. Nothing controls them in the natural system, and they are better at filtering food out of the water than their native cousins. “Invasives use up the lion’s share of resources, and whatever biodiversity that was there falls apart,” Ziska says.

When new interlopers take hold, one or two tend to become very well suited for that environment and dominate it. The natural biodiversity diminishes, Ziska says. Scientists are beginning to catalogue and classify native and nonnative species at ports near oil facilities in Alaska. No large obvious invasions by marine traffic have occurred yet in the high latitude environment but Ziska and others scientists say no one can be sure. Scientists are only now beginning to look closely.

“We weren’t expecting the Arctic to change this quickly,” Ziska notes, adding that the implications for not only human traffic but also for biology are worrisome. “It’s basically opening up the entire Arctic region as a huge playground for invasive species. New things, new biological organisms are going into the area where they have never been seen before. The consequences of that are, quite frankly, are completely unknown.”

Source: Scientific American.

Concerns raised over ‘useless’ Arctic oil spill plan.


oil spillartic

Environmental campaigners say that a draft plan to respond to an oil spill in the Arctic ocean is inadequate and vague.

The proposal has been in preparation for two years as oil companies look to increase exploration in the region.

Greenpeace says it fails to get to grip with the risks of an accident in an extremely sensitive location.

Ministers from the eight nation Arctic Council are due to discuss the plan at a meeting in Sweden tomorrow.

As summer ice in the Arctic has declined in recent years, the area has become the subject of intense interest from oil and gas companies.Estimates from the US Geological Survey indicated that there could be 60 billion barrels of oil in the region.

Glaring hole

In 2011 The Arctic Council members signed the Nuuk Declaration that committed them to develop an international agreement on how to respond to oil pollution in the northern seas.

Now Greenpeace have released a draft of the plan that they say is simply inadequate.

“The big glaring hole is that it is such a vaguely worded document that it doesn’t seem to force countries into doing anything,” Ben Ayliffe from Greenpeace told BBC News.

“For all intents and purposes it is a useless document,” he said.

The plan says that “each party shall maintain a national system for responding promptly and effectively to oil pollution incidents” without requiring any clear details on the number of ships or personnel that would be needed to cope with a spillage.

 

Ben Ayliffe says he believes the Arctic Council plan would be ineffective if a spill occurred.

“It would be a nightmare scenario, you’re facing oil drifting for thousands of miles under ice, the technical challenge of operating in darkness would make mounting the sort of response that BP had to do in the Gulf, completely impossible,” he said.

Late last year, the House of Commons environmental audit committee called for a halt to oil drilling in the Arctic until a pan-Arctic response plan was in place. They called for a stricter financial liability regime to require oil and gas companies to prove they could meet the costs of cleaning up a spill.

According to chair of the Committee Joan Walley MP, there were big questions over the abilities of these companies to deal with a spillage.

“The infrastructure to mount a big clean-up operation is simply not in place and conventional oil spill response techniques have not been proven to work in such severe conditions,” she said.

The Arctic Council consists of the United States, Russia, Canada, Norway, Sweden, Finland, Denmark and Iceland.

Source: BBC

 

SUCCESS! Shell stops Arctic oil drilling for this year.


For over six months, huge numbers of us have been pressuring Shell to stay out of the Arctic. Well this morning, company bosses announced they were scrapping their oil drilling programme for this year. It’s a huge victory for people power.

We started six months ago in New Zealand, when Lucy Lawless climbed and occupied Shell’s Noble Discoverer rig, as it started its long journey up to drill in the Arctic. As Lucy said, “six activists went up, but 133,000 came down“.

But that was only the beginning.

As thousands of you spread the word of the unparalleled insanity that is Arctic drilling, more and more people became involved.

When Penelope Cruz, Sir Paul McCartney and One Direction joined the growing voices calling out for Arctic protection it was obvious that this movement was going to keep growing.

And today together we’ve landed a major victory.

As one of the world’s biggest oil companies, Shell was set to lead the pack and spark the Arctic oil rush. But a few hours ago they admitted defeat for 2012.

With the eyes of two million people on them, Shell executives knew that any mistakes would be noticed. And today they admitted yet another one. A special dome which was designed to clean up after a spill has been damaged. That means the end of the project for this year.

By shining a light in the far frozen corners of this planet, together we’ve helped keep risky oil drilling out of the Arctic – for this year.

The significance of Shell stopping oil drilling is hard to overestimate. After sinking five billion dollars into its failing programme, other oil giants are now questioning the logic of Arctic drilling. Only a few days ago, the Norwegian company Statoil said it was going to wait and see how Shell gets on in the Arctic.

Well today’s news makes it totally clear: Shell’s Arctic misadventure is an expensive and risky mistake.

Thank you to the thousands of volunteers around the world on high streets, petrol stations, universities and places of work who’ve shown what a movement can do.

This is a huge step forward in our campaign, but we need to build on it to make sure we keep the Arctic protected from all oil drillers, for good.

If you’re one of the two million who’ve joined the campaign to save the Arctic – today is a time to celebrate what you’ve achieved against one of the most powerful corporations on the planet. If you’re not, please join now to make the movement even stronger: savethearctic.org

Source: savethearctic.org

http://www.greenpeace.org

 

Arctic ice melt ‘like adding 20 years of CO2 emissions’.


The loss of Arctic ice is massively compounding the effects of greenhouse gas emissions, ice scientist Professor Peter Wadhams has told BBC Newsnight.

White ice reflects more sunlight than open water, acting like a parasol.

Melting of white Arctic ice, currently at its lowest level in recent history, is causing more absorption.

Prof Wadhams calculates this absorption of the sun’s rays is having an effect “the equivalent of about 20 years of additional CO2 being added by man”.

The Cambridge University expert says that the Arctic ice cap is “heading for oblivion”.

In 1980, the Arctic ice in summer made up some 2% of the Earth’s surface. But since then the ice has roughly halved in area.

“Thirty years ago there was typically about eight million square kilometres of ice left in the Arctic in the summer, and by 2007 that had halved, it had gone down to about four million, and this year it has gone down below that,” Prof Wadhams said.

And the volume of ice has dropped, with the ice getting thinner:

“The volume of ice in the summer is only a quarter of what it was 30 years ago and that’s really the prelude to this final collapse,” Prof Wadhams said.

Parts of the Arctic Ocean are now as warm in summer as the North Sea is in winter, Prof Wadhams said.

Radiation absorbed

The polar ice cap acts as a giant parasol, reflecting sunlight back into the atmosphere in what is known as the albedo effect.

But white ice and snow reflect far more of the sun’s energy than the open water that is replacing it as the ice melts.

Instead of being reflected away from the Earth, this energy is absorbed, and contributes to warming:

“Over that 1% of the Earth’s surface you are replacing a bright surface which reflects nearly all of the radiation falling on it with a dark surface which absorbs nearly all.

“The difference, the extra radiation that’s absorbed is, from our calculations, the equivalent of about 20 years of additional CO2 being added by man,” Prof Wadhams said.

If his calculations are correct then that means that over recent decades the melting of the Arctic ice cap has put as much heat into the system as all the CO2 we have generated in that time.

And if the ice continues to decline at the current rate it could play an even bigger role than greenhouse gases.

UK weather effect

Professor Wadhams stresses that there are uncertainties – cloud cover over the Arctic could change and help reflect back some of the sun’s radiation.

But then another greenhouse gas – methane, currently trapped in the Arctic permafrost – could be released with warming and make matters worse.

The melting ice could have knock-on effects in the UK. Adam Scaife, from the Met Office Hadley Centre told Newsnight it could help explain this year’s miserable wet summer, by altering the course of the jet stream.

“Some studies suggest that there is increased risk of wet, low pressure summers over the UK as the ice melts.”

There may be an effect for our winters too: “Winter weather could become more easterly cold and snowy as the ice declines,” Mr Scaife said.

Opinions vary on the date of the demise of summer sea ice. The Met Office says it is not expecting the Arctic to be completely ice-free in summer until after 2030.

Source: BBC.

 

 

Ozone Hole and The Global Climate Changes.


The release of CFCs or chlorofluorocarbons into the atmosphere through human activities has caused a massive hole in the ozone layer right above Antarctica and if unchecked, melting icecaps may inundate several regions of the earth in the future.

What is Ozone and Where Is It Found in The Earth’s Atmosphere?

Ozone is a gas with a pungent odor whose molecule contains three oxygen atoms. At about 6–10 miles above the Earth’s surface and extending up to 30 miles, in a region of space called the stratosphere, you will find 90% ozone. The stratospheric region with the highest ozone concentration is commonly known as the “ozone layer”. The remaining ozone, about 10%, is found in the troposphere, which is the lowest region of the atmosphere, between Earth’s surface and the stratosphere.

Ozone at ground level in the troposphere is bad because it causes photochemical smog. The smog results when ultra-violet light falls on and reacts with nitrogen oxide from vehicle exhausts. Because of this, Ozone affects lung function, aggravates asthma and other chronic respiratory diseases.

On the other hand, ozone in the stratosphere performs a very useful function by acting as a blanket that blocks most of the sun’s high-frequency ultraviolet rays. These UV rays can cause skin cancer and cataracts in humans, as well as reproductive problems in several forms of life including even the single-celled phytoplankton at the bottom of the ocean food chain.

How Does Ozone Form in the Atmosphere?

When ultraviolet light strikes oxygen molecules containing two oxygen atoms (O2), it splits them into individual oxygen atoms (atomic oxygen), which then combines with unbroken O2 to create ozone, O3. Being unstable, this ozone once again splits into a molecule of O2 and an atom of atomic oxygen under the action of ultraviolet light. This continuing process called the ozone-oxygen cycle.

The ozone layer  is very effective at screening out UV-B; Nevertheless, some UV-B, particularly at its longest wavelengths, reaches the surface. Ozone cannot stop UV-A, the longer wavelength ultraviolet radiation which  reaches the earth’s surface. However, this type of UV radiation is significantly less harmful to DNA.

The thickness of the ozone layer varies widely throughout the world, being smaller near the equator and larger towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn in the northern hemisphere.

Ozone ‘Hole’

In May 1985 scientists with the British Antarctic Survey announced the discovery of a huge hole in the ozone layer over Antarctica. They announced that Ozone levels over the northern hemisphere had been dropping by 4% per decade. They described the larger seasonal drops in the ozone levels around the south pole as a ozone hole.

The ozone hole is not technically a “hole” with no ozone is present, but is actually a region of exceptionally depleted ozone in the stratosphere over the Antarctic during the Southern Hemisphere spring (August–October).

Stratospheric temperatures in the Northern Hemisphere during winter/spring are generally slightly warmer than those in the Southern Hemisphere. Therefore ozone losses over the Arctic have been much smaller than over the Antarctic during the 1980s and early 1990s. However, the Arctic stratosphere has gradually cooled over the past few decades, and Ozone holes have been observed at the Arctic regions too recently. This is a dangerous trend, because unlike the Southern Polar hemisphere, the Northern Polar hemisphere is well populated.

Ozone hole is caused by chemicals called CFCs, or chlorofluorocarbons. CFCs escape into the atmosphere from refrigeration and propellant devices and processes. In the lower atmosphere, they are so stable that they persist for decades. Eventually, some of the CFCs reach the stratosphere where chemical reactions take place primarily on the surface of polar stratospheric clouds, ice particles, or liquid droplets, which form at high altitudes in the extreme cold of the polar regions. Ultraviolet light breaks the bond holding chlorine atoms (Cl) to the CFC molecule. Chlorine then destroys ozone molecules by “stealing” their oxygen atoms. The breakdown of ozone in the stratosphere makes it unable to absorb ultraviolet radiation. Consequently, the unabsorbed ultraviolet-B radiation is able to reach the Earth’s surface. The extent of ozone destruction is extremely sensitive to small changes in stratospheric temperature.

Another culprit responsible for the ozone depletion is nitrous oxide (N2O). The major sources of nitrous oxide are industrial processes and combustion engines of various vehicles. They are also emitted from livestock manure and sewage. Like CFCs, Nitrous oxide  is stable when emitted at ground level, but breaks down when it reaches the stratosphere to form nitrogen oxides that trigger ozone-destroying reactions.

In 1987 several UN countries gathered at Montreal, Canada, and signed a treaty to protect the stratospheric ozone layer. The Montreal Protocol stipulated that the production and consumption of compounds that deplete ozone in the stratosphere—chlorofluorocarbons, halons, carbon tetrachloride, and methyl chloroform—are to be phased out by 2005.

Chemical manufacturers soon created substitutes for CFCs with little added costs; thus, our life styles remained greatly unaffected by the switch-over from CFC’s. This has had the effect of putting a slow stopper on the Ozone hole.

Now, the issue of a possible connection between ozone hole and global warming is a controversial subject even among scientists. In fact, there is no unanimity in either of the assertions that Antarctica is warming or cooling. The British Antarctic Survey says categorically Antarctica to be both warming around the edges and cooling at the center at the same time. Thus it is not possible to say whether it is warming or cooling overall. Because there are too many parameters governing the global temperatures, it is difficult to correlate the theoretical temperature rise at the Antarctic caused by a thinner ozone layer with global climatic changes. It is useful to remember here that Ozone itself is a greenhouse gas and its thinning over the region reduces heat trapped over it and helps create sea spray that forms reflective, cooling clouds.

Source: http://scienceray.com