Pictures: 11 Most Endangered U.S. Historic Sites Named

Soldier's Home, Wisconsin

Fort Gaines, Alabama

Isaac Manchester Farm, Pennsylvania

China Alley, California

Pillsbury "A" Mill Complex, Minnesota

Greater Chaco Landscape, New Mexico

Prentice Women's Hospital, Illinois

Bear Butte, South Dakota

Belmead-on-the-James, Virginia

John Coltrane Home, New York

Sun has a solar blast

The Sun unleashed an M-2 (medium-sized) solar flare, an S1-class (minor) radiation storm and a spectacular coronal mass ejection (CME) on June 7, 2011 from sunspot complex 1226-1227. The large cloud of particles mushroomed up and fell back down looking as if it covered an area of almost half the solar surface.

The Solar Dynamics Observatory (SDO) observed the flare's peak at 1:41a.m. ET (0641 UT). SDO recorded these images (above) in extreme ultraviolet light that show a very large eruption of cool gas. It is somewhat unique because at many places in the eruption there seems to be even cooler material — at temperatures less than 80,000 K.

When viewed in Solar and Heliospheric Observatory's (SOHO) coronagraphs (right), the event shows bright plasma and high-energy particles roaring from the Sun. This not-squarely Earth-directed CME is moving at 1400 km/s according to NASA models.

The CME should deliver a glancing blow to Earth's magnetic field during the late hours of June 8th or June 9th. High-latitude sky watchers should be alert for auroras when the CME arrives.

Magnetic bubbles fill edge of solar system

  

The edge of the solar system is filled with a turbulent sea of magnetic bubbles, astronomers said Thursday.

The finding changes ideas about the distant region and how the rest of the galaxy interacts with the solar system.

The two Voyager spacecraft, which have spent more than three decades travelling toward the outer boundaries of our solar system, found unexpected changes in the magnetic field that extends outward from the Sun. This discovery was made once they reached the heliosheath, as the outer part of the solar system is called.

The long sausage-shaped magnetic bubbles are approximately 160 million kilometres wide. A computer model was used to crunch data from the spacecraft to postulate their existence, as they cannot be seen with the eye.

They make the area very turbulent, “just like the bubbliest parts of your jacuzzi,” said University of Maryland astronomer James Drake.

The finding means that damaging galactic cosmic rays entering the solar system from the rest of the galaxy must first pass through the sea of bubbles, causing them to bounce around like inside a pinball machine before finally entering the solar system.

Scientists have long measured the rays, which can have damaging health effects for astronauts, but this could change theories about the rays and how they reach us from interstellar space.

Voyager 1 and Voyager 2 reached the heliosheath in the past decade and are still travelling through it.

Caught on cam : Bride-to-be attempts suicide

Is Armenia's Nuclear Plant the World's Most Dangerous?

Steam rises from the cooling towers of Metsamor nuclear power station in Armenia in September 2010. One of the last old operating Soviet reactors built without containment vessels, its location in a seismic zone has drawn renewed attention since Japan's earthquake-and-tsunami-triggered crisis.

In the shadow of Mount Ararat, the beloved and sorrowful national symbol of Armenia, stands a 31-year-old nuclear plant that is no less an emblem of the country's resolve and its woe.

(Related: Armenia Guide)

The Metsamor power station is one of a mere handful of remaining nuclear reactors of its kind that were built without primary containment structures. All five of these first-generation water-moderated Soviet units are past or near their original retirement ages, but one salient fact sets Armenia's reactor apart from the four in Russia.

Metsamor lies on some of Earth's most earthquake-prone terrain.

In the wake of Japan's quake-and-tsunami-triggered Fukushima Daiichi crisis, Armenia's government faces renewed questions from those who say the fateful combination of design and location make Metsamor among the most dangerous nuclear plants in the world.

Seven years ago, the European Union's envoy was quoted as calling the facility "a danger to the entire region," but Armenia later turned down the EU's offer of a 200 million euro ($289 million) loan to finance Metsamor's shutdown. The United States government, which has called the plant "aging and dangerous," underwrote a study that urged construction of a new one.

Plans to replace Metsamor after 2016—with a new nuclear plant at the same location—are under way. But until then, Armenia has little choice but to keep Metsamor's turbines turning. As Armenians learned in the bone-chilling cold and dark days when the plant was closed down for several years, Metsamor provides more than 40 percent of power for a nation that is isolated from its neighbors and closed off from other sources of energy.

"People compare the potential risk with the potential shortage of electricity that might arise if the plant were closed," says Ara Tadevosyan, director of Mediamax, a major Armenian news agency. "Having had this negative experience, people prefer to live with it, and believe that it will not be damaged in an earthquake."

A Need for Nuclear

The 3 million people of landlocked Armenia are unique in their energy dependence on one aging nuclear power reactor. Regional conflicts that broke out in the dissolution of the Soviet Union left the smallest of its former republics at odds with its neighbors.

Azerbaijan to the east and Turkey to the west closed their borders with Armenia, cutting off most routes for oil and natural gas. The blockade, which remains in place to this day, heaped a new economic wound onto an old scar. After the massacre of more than one million Armenians during World War I and subsequent conflict, the Soviets ceded the western part of the historic Armenian homeland to Turkey. The snow-capped peak of Mount Ararat, still revered in Armenia as the resting place of Noah's Ark, emblazoned on trinkets and storefronts throughout the land, is now in Turkey.

(Related: "Tough Situations in Difficult Countries")

The Metsamor Nuclear Power Plant is just 10 miles (16 kilometers) from the Turkish border—in an area that includes the fertile agricultural region of the Aras River valley. It's only 20 miles (36 kilometers) from the capital of Yerevan, home to one-third of the nation's population. And it is in the midst of a strong seismic zone that stretches in a broad swath from Turkey to the Arabian Sea near India.

On December 7, 1988, a 6.8-magnitude earthquake struck, killing 25,000 people and leaving 500,000 homeless. Some 60 miles (100 kilometers) from the epicenter, Metsamor, then with two operating reactors, survived the temblor without damage, according to Armenian officials and the International Atomic Energy Agency (IAEA). Because the devastating earthquake heightened concerns about the seismic hazard to the facility, the Soviet government shut the nuclear plant down.

Tadevosyan said that public attitudes toward Metsamor have been strongly shaped by the nation's experience living without it during the six-and-a-half years that followed.

"There were severe power shortages during the winter months," he recalled in a telephone interview from Yerevan. "We had a situation where you had one hour of power a day, and sometimes no power at all for a week. You can imagine—it was as cold in the apartment as it was in the street."

A pipeline to import Russian natural gas through neighboring Georgia in the north was built in 1993, but it was regularly interrupted by "sabotage and separatist strife in that country," as the World Bank noted in a 2006 report.

In 1995, the government of then-independent Armenia decided to restart the younger of the two reactors. Richard Wilson, nuclear physics professor emeritus at Harvard University, was part of a delegation of outside experts in Armenia at the time. He recalls that the Russians who came from the airport to help reopen the reactor were cheered from the side of the road upon their arrival.

When the unit restarted, "It became a source of energy and a source of hope for Armenia," explained Tadevosyan. "It was a symbol that dark times are over: 'We have electricity.' And it is still seen as such today."

Fortifying an Old War Horse

Armenian officials say modifications made to the reactor over the past 15 years have made it safer. Before Metsamor was reopened, Armenia airlifted more than 500 tons of equipment to the site (most of it from Russia), for upgrades, according to the Nuclear Energy Institute, an industry group in the United States.

In the years since the restart, the IAEA says close to 1,400 safety improvements have been made. Those included "seismic-resistant" storage batteries, reinforcement of the reactor building, electrical cabinets and cooling towers. The United States provided equipment for a seismic-resistant, spray-pond coolingsystem. Fire safety was viewed as a critical deficiency at the plant, so extensive upgrades were made, including 140 new fire doors.

The result, officials say, is a reactor that is much safer than the original unit that went into service at the site on January 10, 1980. When construction began in 1969, Metsamor was a VVER 440, Model 230, an example of one of the earliest pressurized-water nuclear plant designs, developed by the Soviets between 1956 and 1970. It was not the same design as Chernobyl, which used solid graphite instead of water to moderate—or slow down—the fission reaction. (The graphite fire contributed to the world's worst nuclear disaster, and 11 of these early graphite-moderated reactors continue to operate in Russia.)

(Related: "How is Japan's Nuclear Disaster Different?")

The VVER 440, in contrast, used water both to moderate and to cool the fuel, as in Western designs. (Its initials, in Russian, stand for "water-water-power-reactor.")

In fact, the VVER system, with multiple cooling loops, was seen as "more forgiving" than Western plants, according to archived documents from the International Nuclear Safety Program, a former U.S. Department of Energy program aimed at aiding in safety improvements at Soviet plants. VVER 440 units would be able to stand a power loss for a longer period of time than Western plants because of the large coolant volume.

After Japan's nuclear crisis erupted, the head of the Armenian State Committee on Nuclear Safety Regulation, Ashot Martirosian, pointed to Metsamor's cooling system as one reason Armenians should rest assured. "Such an emergency situation cannot arise here," he told Radio Free Europe.

(Related: "Japan Battles to Avert Nuclear Disaster" and "Pictures—A Rare Look Inside Fukushima Daiichi")

Nuclear engineering expert Robert Kalantari, whose Framingham, Massachusetts, firm, Engineering Planning and Management, consults for U.S. and Canadian regulatory authorities, says Metsamor is like any other nuclear plant in operation worldwide. Although its safety features are different, all have to be able to be shut down safely during a so-called "design basis accident," the kind of accident anticipated in its design. He said he is confident that Metsamor could operate safely in such an accident, and that it could cope even with accidents beyond its design basis.

"Metsamor is no less safe than any other reactor in operation throughout the world," Kalantari said. "Armenia as an independent country cannot survive without [Metsamor], which is a functioning, safe, and reliable source of energy for the country."

Lack of Containment

But the VVER 440s share one characteristic with Chernobyl that has been a continuing concern to many who live nearby: They have no containment structure.

Instead, VVER 440s rely on an "accident localization system," designed to handle small ruptures. In the event of a large rupture, the system would vent directly to the atmosphere. "They cannot cope with large primary circuit breaks," the NEI's 1997 Source Book on Soviet nuclear plants concluded. "As with most Soviet-designed plants, electricity production by the VVER-440 Model V230s came at the expense of safety."

Antonia Wenisch of the Austrian Institute of Applied Ecology in Vienna, calls Metsamor "among the most dangerous" nuclear plants still in operation. A rupture "would almost certainly immediately and massively fail the confinement," she said in an email. "From that point, there is an open reactor building, a core with no water in it, and accident progression with no mitigation at all."

Despite the upgrades to the plant, she said, "the overall safety has not improved sufficiently." She points to Armenia's own most recent report for the international convention on nuclear safety, which estimates the risk of "core damage frequency" to be nearly two incidents every 10,000 years. She said that number should be less than one. The average risk at U.S. nuclear power plants is 2 such incidents every 50,000 years, according to a report by the U.S. Electric Power Research Institute.

Over the past decade, the European Union, living in close proximity to the old Soviet plants, used leverage where it could to get some of them shuttered. Four VVER 440 units in Bulgaria and two in Slovakia were closed as a condition of those countries joining the European Union.

But four of the units remain in operation in Russia—two in the northern city of Murmansk, on the Kola Peninsula near the Barents Sea, and two at Novovoronezh, in the Voronezh region in the west (the area of last summer's devastating Russian forest fires). Metsamor is the only VVER 440, Model 230, operating outside of Russia.

(Related: "Wildfire Pictures—Russia Burns, Moscow Chokes")

Since it failed to persuade Armenia to close the plant, the EU has focused on providing aid for improving its safety, spending more than 59 million euros ($85 million) on such projects as well as for renewable energy, and regional energy cooperation efforts.

Armenia has made efforts to obtain other sources of fuel, such as a natural gas pipeline from its southern neighbor Iran, which opened in 2007. But the amount of fuel to be imported remains in question. The conduit poses potential competition to Russia, a country on which Armenia remains highly reliant, for everything from nuclear fuel to grain. A U.S. Agency for International Development (USAID)-funded study concluded that a new nuclear plant was Armenia's lowest-cost energy option.

Plans for the Future

Armenia intends to break ground on a $5 billion reactor project next year—a larger, and more advanced Russian VVER 1000. The government is going forward with a conference late this month to seek help from potential investors and engineering contractors. The planned reactor would have a containment vessel, but it would be located in the same seismic area as the current Metsamor plant.

Hakob Sanasaryan, a chemist who is chairman of the Greens Union of Armenia, says that although he believes the Metsamor reactor's old design makes it less safe than newer plants, it is the location that is his greatest concern.

Speaking by telephone through an interpreter, he said his group opposes the plan to build a new plant at a place of such high seismic hazard, within Armenia's prime agricultural region, and so close to the country's most populous city. If the government were to reconsider that project in the wake of Japan's crisis, Sanasaryan said, it would be "the only good thing that might possibly come out of these tragic events."

Sanasaryan would like to see Armenia further develop its hydroelectric resources, or more thermal energy from geothermal sources or natural gas. He also has great hope for the country's solar energy potential. "We have existing infrastructure," he says. "If it were exploited better, it could satisfy Armenia's energy needs."

But another Armenian environmentalist, Karine Danielyan, president of Armenia's Association for Sustainable Human Development, laments that there has been insufficient effort over the past 15 years to create a renewable energy base. Danielyan, a former Armenian environment minister, wrote in an email that she is keenly aware of the harm that resulted from the energy shortages during Metsamor's closure. In addition to increased mortality due to the cold, deforestation accelerated rapidly as citizens scavenged for wood to heat their homes. The sharp increase of water flow to ramp up hydroelectricity caused severe stress to the nation's largest lake, Lake Sevan, where efforts at ecological restoration are a continuing battle.

Although she calls herself "an opponent of nuclear power engineering," Danielyan said she was compelled to join the call to improve safety at Metsamor and restart the plant in 1995. Now, she says, the country faces the need to construct another nuclear plant. "Unfortunately, now Armenia has not another alternative," she says.

Radiation in Japan Seas: Risk of Animal Death, Mutation?

Aboard a boat pulling a barge with water for Japan's overheating Fukushima nuclear plant Thursday.

If radioactive material from the Fukushima Daiichi nuclear power plant—disabled by the March11 Japan earthquake and tsunami—continues to enter the ocean, marine life could be threatened, experts say.In the past week, seawater samples taken near the nuclear power plant, onJapan's eastern coast, have shown elevated levels of radioactive isotopes, including cesium 137 and iodine 131, according to the New York Times. (See "Japan Tries to Avert Nuclear Disaster.")All life on Earth and in the oceans lives with exposure to natural levels of ionizing radiation—high-frequency radiation with enough energy to change DNA. Most such genetic damage heals, but the addition of human-made radiation can make it harder for the body to repair broken genes.Radiation concentrations in the Japanese seawater samples have fluctuated in past days, but on Wednesday the amount of iodine spiked to 3,355 times the legal limit for seawater, Japanese nuclear safety officials told the Associated Press.That level is the highest so far—and an indication that more radiation is entering the ocean, though how is still unknown, the agency reported. Cesium was also found to be 20 times its safety limit on March 28, according to the Times.

Radiation Can Cause "Bizarre Mutations"nce in seawater, radiation can hurt ocean animals in several ways—by killing them outright, creating "bizarre mutations" in their offspring, or passing radioactive material up the food chain, according to Joseph Rachlin, director of Lehman College's Laboratory for Marine and Estuarine Research in New York City."There will be a potential for a certain amount of lethality of living organisms, but that's less of a concern than the possible effects on the genetics of the animals that become exposed," Rachlin said."That's the main problem as I see it with radiation—altering the genetics of the animal and interfering with reproduction."Even so, according to radioecologist F. Ward Whicker, the concentrations of iodine and cesium levels "would have to be orders of magnitude larger than the numbers I've seen to date to cause the kind of radiation doses to marine life that would cause mortality or reductions in reproductive potential."I am very doubtful that direct effects of radioactivity from the damaged reactors on marine life over a large area off the coast of Japan will be observed," Whicker, professor emeritus at Colorado State University, said via email.

Likewise, using legal limits to gauge damage to marine life is of little value right now, he said.

To make a "credible assessment" of the risk to marine animals, scientists would have to know the actual concentrations of radioactive iodine in the water and fish or other marine animals off Fukushima Daiichi, he said.

Radiation Hardest on the Little Ones

It's possible that levels of radioactive contamination near the Fukushima nuclear reactors could increase and cause some harm to local marine life, Whicker said.

"If this happens, the most likely effects would be reductions in reproductive potential of local fishes. ... ," he said.

Marine organisms' eggs and larvae are highly sensitive to radiation, since radioactive atoms can replace other atoms in their bodies, resulting in radiation exposure that could alter their DNA, Whicker said. (Get the basics on genetics.)

Most such deformed organisms don't survive, but some can pass abnormalities on to the next generation, Lehman College's Rachlin said. Either way, the radiation exposure could hurt the population's ability to survive long-term.

Rachlin thinks the most susceptible critters would be soft-bodied invertebratessuch as jellyfish, sea anemones, and marine worms—which can take up the radiation more quickly than shelled creatures—though Whicker said fish may be most at risk.

Whicker added, "I would expect any temporary losses in reproduction in local fish to be offset by immigration of unaffected individuals from surrounding areas that would be impacted to a lesser degree."

(See "Chernobyl Birds' Defects Link Radiation, Not Stress, to Human Ailments.")

In addition to its threats to reproduction, pockets of radioactive material can can burn fish passing through, hitting them like a stream of searing water, Rachlin said.

Complicating matters is the fact that predator species in the Pacific such as tuna and sailfish are already stressed by overfishing, according to Rachlin.

"I'm concerned—this is the spawning season. ... If this impacts the survivorship of the young and larvae, this will be a further insult."

Radiation Threat Here to Stay?

According to chemical oceanographer Bill Burnett, "In the short run [the radiation] could have some definite negative impacts" on marine life.

"The good news is the half life [of iodine] is only eight days," added Burnett, an expert in environmental radioactivity at Florida State University.

So "if they stop the source of radioactive leakage, this is going to be a short-term problem."

However Fukushima Daiichi's leaking cesium is potentially more serious, since that isotope takes 30 years to decay, Burnett said.

Radiation Can Travel Up the Food Chain

There could also be some movement of radiation up the food chain if animals eat irradiated plants and smaller, radioactive animals, Rachlin said.

In particular, plants such as kelp can quickly absorb iodine, FSU's Burnett said. (See pictures of ocean wildlife.)

There's a possibility that the devastation of towns in northeastern Japan caused by the earthquake and tsunami also released toxic metals such as lead into the soil and water, according to Texas Tech University ecotoxicologist Ron Kendall.

Previous studies have shown that metals can work in concert with radiation to suppress immune systems in vertebrates, making them more vulnerable to disease, Kendall said.

It's a "big issue for the environment and human health because of the widespread destruction. It takes me back to New Orleans after Hurricane Katrina—this to me is even more complicated with the radiation."

(See photos: "Japan Reactor Crisis: Satellite Pictures Reveal Damage.")

Ocean Resilient Against Radiation

The ocean has a "tremendous capacity" for diluting radiation, Colorado State's Whicker noted.

"It also has resilience, in the sense that the area would recover over time as the situation improves and as the radioactivity decays and disperses."

"But I should caution that we have not had much opportunity to study the effects of very large releases of radioactivity into marine ecosystems," he said. The best data comes from nuclear weapons tests in the Pacific in the 1950s and 1960s.

Texas Tech's Kendall also pointed out that there's not much known about radiation in seawater.

"The dose makes the poison," he said, "and the more concentrated the radiation, the more potential effects. It's something we definitely need to monitor."

Added Lehman's Rachlin: "If it's a one-shot pulse, OK, not a problem.

But if the radiation leaks continue for several months, Japan may be dealing with a more serious blow to marine life, he said.

The coastline, after all, isn't Chernobyl, he said. "We can't cement [over] that whole area."

Criminals target mobile devices and social networks

Smartphones and social networking sites are likely to become the next big target for cyber criminals, according to a security industry report.

Symantec's annual threat analysis warns that the technologies are increasingly being used to spread malicious code.

Users of Facebook, Twitter and Google's mobile operating system, Android, are said to be particularly vulnerable.

However, the number of attacks remains small compared to other online crimes such as e-mail phishing.

According to Symantec, known vulnerabilities in mobile operating systems rose from 115 in 2009 to 163 in 2010.

In several cases, the security holes were exploited and used to install harmful software on Android handsets - suggesting that criminals now view smartphone hacking as a potentially lucrative area .

At least six different varieties of malware were discovered hidden in applications that were distributed through a Chinese download service.

"It is something we have started to see happen, albeit on a small level," said Orla Cox, security operations manager at Symantec.

"It allows people to do a variety of things from intercepting SMS messages to dialling toll numbers. They have opened up the possibility of what is there."

Several pieces of malware were also found on iPhones, however only devices that had been "jailbroken" to bypass Apple's security were affected.

The company's process of pre-vetting all new applications is believed to have spared its devices from a major attack.

Rogue applications

Continue reading the main story

2010 Internet Security Threat Report

• 286 million - number of unique variants of malware detected.
• 1 million - number of zombie computers controlled by Rustock botnet.
• 260,000 - average number of personal identities exposed in each corporate attack.
• 6,253 - number of new software vulnerabilities that could be used by criminals.
• 42% - increase in the number of vulnerabilities on smartphones.
• 14 - number of never-before-seen 'zero day' vulnerabilities that first turn up in malware.

Source: Symantec

On Facebook and Twitter, Symantec's analysis highlighted several different types of threat.

Among the most prevalent were web links that encourage users to click through to other sites containing malware and rogue applications, designed to collect personal information.

The company estimates that one in six links posted on Facebook pages are connected to malicious software.

User information is said to be particularly valuable in "social engineering" attacks, where criminals use knowledge of an individual to trick them into scams that appear to relate to them personally.

The report also raises concerns about shortened URLs, such as http://tiny.cc/jumqm.

Such systems are widely used to shorten web addresses, but they also make it harder to tell what the target site is. Sixty-five per cent of malware links on social networking websites were found to use shortened URLs.

Attack toolkits

Symantec makes its money selling internet security software and services to individuals and corporations

Its annual Internet Security Threat Report - based on data supplied by users around the world - is generally regarded as a reliable measure of changing trends in cyber crime.

Globally, the company recorded a 93% increase in the volume of web-based attacks between 2009 and 2010.

The dramatic rise was largely attributed to the widespread availability of "attack toolkits" - software packages that allow users with relatively little skill to design their own malicious software.

Toolkits are available to buy online for as little as a few pounds and as much as several thousand for the latest versions.

The most popular attack kit was Phoenix, which exploits vulnerabilities in the Java programming language - commonly used for web-based applications.

Iran's Bushehr nuclear plant is believed to have been one of Stuxnet's targets

Symantec's report also notes a rise in the number of targeted attacks, where specific companies, organisations or individuals are singled out.

The most sensational targeted attack of 2010 was undoubtedly Stuxnet. The software worm was designed to take control of mechanical systems used in Iran's nuclear plants.

It has been widely speculated that the USA or Israel may have played a role in its creation.

Despite Stuxnet's headline-grabbing nature, Orla Cox believes that it may not be indicative of things to come.

"It was interesting to see that it is possible to attack physical systems. I think it unlikely that we will see a whole slew of attacks of that nature," she said.

the North Pole Ozone Layer

Unusually low temperatures in the Arctic ozone layer have recently initiated massive ozonedepletion. The Arctic appears to be heading for a record loss of this trace gas that protects the Earth's surface against ultraviolet radiation from the sun. This result has been found by measurements carried out by an international network of over 30 ozone sounding stations spread all over the Arctic and Subarctic and coordinated by the Potsdam Research Unit of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association in Germany. In the Arctic the amount lost is more variable year-to-year than in the Antarctic. The greatest declines, up to 30%, are in the winter and spring, when the stratosphere is colder

The Arctic winter of 2005 was also extremely cold in the stratosphere. The size of the Arctic area of anomalously low total ozone in 2004-2005 was larger than in any year since 1997. The predominance of anomalously low total ozone values in the Arctic region in the winter of 2004-2005 is attributed to the very low stratospheric temperatures and meteorological conditions favorable for ozone destruction along with the continued presence of ozone destroying chemicals in the stratosphere.

"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," says AWI researcher Markus Rex, describing the current 2011 situation. "Since the conditions leading to this unusually rapid ozone depletion continue to prevail, we expect further depletion to occur." The changes observed at present may also have an impact outside the thinly populated Arctic. Air masses exposed to ozone loss above the Arctic tend to drift southwards later. Hence, due to reduced UV protection by the severely thinned ozone layer, episodes of high UV intensity may also occur in middle latitudes. "Special attention should thus be devoted to sufficient UV protection in spring this year," recommends Rex.

Ozone is lost when breakdown products of anthropogenic chlorofluorocarbons (CFCs) are turned into aggressive, ozone destroying substances during exposure to extremely cold conditions. For several years now scientists have pointed to a connection between ozone loss and climate change, and particularly to the fact that in the Arctic stratosphere at about 20 kilometer altitude, where the ozone layer is, the coldest winters seem to have been getting colder and leading to larger ozone losses.

"The current winter is a continuation of this development, which may indeed be connected to global warming," atmosphere researcher Rex explains the connection that appears paradoxical only at first glance. "To put it in a simplified manner, increasing greenhouse gas concentrations retain the Earth's thermal radiation at lower layers of the atmosphere, thus heating up these layers. Less of the heat radiation reaches the stratosphere, intensifying the cooling effect there." This cooling takes place in the ozone layer and can contribute to larger ozone depletion. "However, the complicated details of the interactions between the ozone layer and climate change haven't been completely understood yet and are the subject of current research projects," states Rex.

A 2005 IPCC summary of ozone issues concluded that observations and model calculations suggest that the global average amount of ozone depletion has now approximately stabilized. Although considerable variability in ozone is expected from year to year, including in polar regions where depletion is largest, the ozone layer is expected to begin to recover in coming decades due to declining ozone-depleting substance concentrations, assuming full compliance with theMontreal Protocol.

In the long term the ozone layer will recover thanks to environmental policy measures enacted for its protection. This winter's likely record-breaking ozone loss does not alter this expectation. "By virtue of the long-term effect of the Montreal Protocol, significant ozone destruction will no longer occur during the second half of this century," explains Rex. The Montreal Protocol is an international treaty adopted under the UN umbrella in 1987 to protect the ozone layer and for all practical purposes bans the production of ozone-depleting chlorofluorocarbons (CFCs) worldwide today.

CFCs released during prior decades however, will not vanish from the atmosphere until many decades from now. Until that time the fate of the Arctic ozone layer essentially depends on the temperature in the stratosphere at an altitude of around 20 kilometers and is thus linked to the development of earth's climate.