Satellites show that the recent ozone hole over Antarctica was the smallest seen in the past decade. Long-term observations also reveal that Earth’s ozone has been strengthening following international agreements to protect this vital layer of the atmosphere.
According to the ozone sensor on Europe’s MetOp weather satellite, the hole over Antarctica in 2012 was the smallest in the last 10 years.
The instrument continues the long-term monitoring of atmospheric ozone started by its predecessors on the ERS-2 and Envisat satellites.
Since the beginning of the 1980s, an ozone hole has developed over Antarctica during the southern spring - September to November - resulting in a decrease in ozone concentration of up to 70%.
Ozone depletion is more extreme in Antarctica than at the North Pole because high wind speeds cause a fast-rotating vortex of cold air, leading to extremely low temperatures. Under these conditions, human-made chlorofluorocarbons - CFCs - have a stronger effect on the ozone, depleting it and creating the infamous hole.
Intentionally engineering Earth’s atmosphere to offset rising temperatures could be far more doable than you imagine, says David Keith. But is it a good idea?
Here is the plan. Customize several Gulfstream business jets with military engines and with equipment to produce and disperse fine droplets of sulfuric acid. Fly the jets up around 20 kilometers—significantly higher than the cruising altitude for a commercial jetliner but still well within their range. At that altitude in the tropics, the aircraft are in the lower stratosphere. The planes spray the sulfuric acid, carefully controlling the rate of its release. The sulfur combines with water vapor to form sulfate aerosols, fine particles less than a micrometer in diameter. These get swept upward by natural wind patterns and are dispersed over the globe, including the poles. Once spread across the stratosphere, the aerosols will reflect about 1 percent of the sunlight hitting Earth back into space. Increasing what scientists call the planet’s albedo, or reflective power, will partially offset the warming effects caused by rising levels of greenhouse gases.
The author of this so-called geoengineering scheme, David Keith, doesn’t want to implement it anytime soon, if ever. Much more research is needed to determine whether injecting sulfur into the stratosphere would have dangerous consequences such as disrupting precipitation patterns or further eating away the ozone layer that protects us from damaging ultraviolet radiation. Even thornier, in some ways, are the ethical and governance issues that surround geoengineering—questions about who should be allowed to do what and when. Still, Keith, a professor of applied physics at Harvard University and a leading expert on energy technology, has done enough analysis to suspect it could be a cheap and easy way to head off some of the worst effects of climate change.
“Bull!” said Kerry Emanuel, an atmospheric scientist at MIT.
Jim Anderson of Harvard University was showing him some weird data he had collected. Since 2001, Anderson and his team had been studying powerful thunderstorms by packing instruments into repurposed spy planes and B-57 bombers, among the only planes capable of flying into the storms “without having their wings ripped off,” Anderson said. To his puzzlement, the instruments detected surprisingly high concentrations of water molecules in the stratosphere, the usually drier-than-dust uppermost layer of the atmosphere. They found the water over thunderstorms above Florida, and they found it over thunderstorms in Oklahoma—water as out of place as a dolphin in the Sahara.
While water in the stratosphere might seem innocuous, the finding made Anderson “profoundly worried,” he recalls. From the decades he had spent studying the depletion of the earth’s ozone layer—the thin gauze of molecules in the stratosphere that blocks most incoming ultraviolet radiation—Anderson knew that water could, through a series of chemical reactions, destroy ozone.
It was when he told Emanuel that violent thunderstorms seemed to be heaving water high into the atmosphere that his MIT colleague expressed his skepticism. A quick back-of-the-envelope calculation showed “you’d need an updraft of 100 miles an hour” to do that, Emanuel said. Impossible.
Anderson persisted, and by early 2012 he had demonstrated the connection. Scrutinizing data from the high-altitude flights, he showed that summer thunderstorms were indeed injecting water molecules into the stratosphere. There, sulfate aerosols (from industrial pollutants as well as volcanoes) attract the water molecules like a sponge and, plumped up, provide a bed for chemical reactions that destroy ozone. The destruction can persist for days or weeks. Oh, and one more thing: The violent storms that inject water vapor into the stratosphere might be getting more powerful and more frequent under the influence of global warming
Bad news, everyone. Researchers have discovered that 15% of the coral trout living in Australia’s great Barrier Reef are suffering from what’s been described as a scalier version of melanoma, a deadly form of skin cancer. That’s unsettling for a number of reasons, but there are two big ones that should immediately give you pause.
1) This is the first case of melanoma ever documented in a wild fish population.
2) The Great Barrier Reef is directly beneath a gaping hole in Earth’s ozone layer.
In other words, this is the first (disturbingly strong) evidence that fish are developing skin cancer from ultraviolet radiation outside of a research laboratory. Two coral trout with melanoma can be seen up top (far left and center). A healthy coral trout, pictured above on the far right, shows that the fish is usually completely orange. Writes Science NOW’s Krystnell Storr:
For the past 25 years, it seemed that we’d pretty much solved the ozone problem. In the 1970s and 80s, people around the world grew increasingly alarmed as research revealed that chemicals we were producing—such as CFCs, used in refrigeration— had started destroying the crucial ozone layer, high up in the atmopshere, that protects us from the sun’s harmful UV radiation. In response, world governments came together to sign the Montreal Protocol in 1987, which phased out the production of ozone-depleting chemicals. The concentration of these chemicals in the atmosphere leveled off within a decade.
Yesterday, though, Harvard scientists hit us with some bad news: It looks as if climate change could actually cause the depletion of the ozone layer to resume on a wide scale, with grim implications for the United States.
“If you were to ask me where this fits into the spectrum of things I worry about, right now it’s at the top of the list,” said professor James Anderson in a press release, discussing his team’s paper, published online in Science. “What this research does is connect, for the first time, climate change with ozone depletion, and ozone loss is directly tied to increases in skin cancer incidence, because more ultraviolet radiation is penetrating the atmosphere.”
The revelation comes from the researchers’ observation that warm-temperature summer storms can force moisture high up into the stratosphere, a layer of the atmosphere that sits about 6 miles above our heads. Typically, storm updrafts are halted at a boundary just below the stratosphere, but in a series of observation flights above the U.S., the team saw that storms with sufficient power injected water vapor into the stratosphere via convection currents.
Strong summer thunderstorms that pump water high into the upper atmosphere pose a threat to the protective ozone layer over the United States, researchers said on Thursday, drawing one of the first links between climate change and ozone loss over populated areas.
In a study published online by the journal Science, Harvard University scientists reported that some storms send water vapor miles into the stratosphere — which is normally drier than a desert — and showed how such events could rapidly set off ozone-destroying reactions with chemicals that remain in the atmosphere from CFCs, refrigerant gases that are now banned.
The risk of ozone damage, scientists said, could increase if global warming leads to more such storms.
“It’s the union between ozone loss and climate change that is really at the heart of this,” said James G. Anderson, an atmospheric scientist and the lead author of the study.
For years, Dr. Anderson said, he and other atmospheric scientists were careful to keep the two concepts separate. “Now, they’re intimately connected,” he said.
Ozone helps shield people, animals and crops from damaging ultraviolet rays from the sun. Much of the concern about the ozone layer has focused on Antarctica, where a seasonal hole, or thinning, has been seen for two decades, and the Arctic, where a hole was observed last year. But those regions have almost no population.
A thinning of the ozone layer over the United States during summers could mean an increase in ultraviolet exposure for millions of people and a rise in the incidence of skin cancer, the researchers said.
In the ramshackle apartment blocks and sooty concrete homes that line the dusty roads of urban India, there is a new status symbol on proud display. An air-conditioner has become a sign of middle-class status in developing nations, a must-have dowry item.
It is cheaper than a car, and arguably more life-changing in steamy regions, where cooling can make it easier for a child to study or a worker to sleep.
But as air-conditioners sprout from windows and storefronts across the world, scientists are becoming increasingly alarmed about the impact of the gases on which they run. All are potent agents of global warming.
Air-conditioning sales are growing 20 percent a year in China and India, as middle classes grow, units become more affordable and temperatures rise with climate change. The potential cooling demands of upwardly mobile Mumbai, India, alone have been estimated to be a quarter of those of the United States.
Air-conditioning gases are regulated primarily though a 1987 treaty called the Montreal Protocol, created to protect the ozone layer. It has reduced damage to that vital shield, which blocks cancer-causing ultraviolet rays, by mandating the use of progressively more benign gases. The oldest CFC coolants, which are highly damaging to the ozone layer, have been largely eliminated from use; and the newest ones, used widely in industrialized nations, have little or no effect on it.
F. Sherwood Rowland, the UC Irvine chemistry professor who warned the world that man-made chemicals could erode the ozone layer, has died. He was 84.
Rowland, known as Sherry, died Saturday at his home in Corona del Mar of complications from Parkinson’s disease, the university announced.
In 1995, Rowland was one of three people awarded the Nobel Prize in chemistry for his work explaining how chlorofluorocarbons, ubiquitous substances once used in an array of products from spray deodorant to industrial solvents, could destroy the ozone layer, the protective atmospheric blanket that screens out many of the sun’s harmful ultraviolet rays.
The prize was awarded more than two decades after Rowland warned of the problem, and challenges to his theory plagued him for many years before he won widespread recognition for his work and leaders of nations worldwide began to act to ban or reduce usage of the chemicals.
“We have lost our finest friend and mentor,” Kenneth C. Janda, UC Irvine physical sciences dean, said Sunday in an email to faculty. “He saved the world from a major catastrophe: never wavering in his commitment to science, truth and humanity, and did so with integrity and grace.”
The discovery “was about more than just stratospheric ozone,” said Donald Blake, a chemistry professor at UC Irvine who worked closely with Rowland for more than two decades. “It was about the whole environment and the realization that something we can do in California could have effects somewhere else in the world. It was the start of the global era of the environment.”