Twenty-five years ago this month, British scientists announced their discovery of the ozone hole over Antarctica. That bolt from the blue spurred perhaps the best-coordinated international response to an environmental crisis to date. Now, scientists can’t help but wonder: Why didn’t the same thing happen with climate change?
Looking back on the ozone problem: Even before the discovery of the hole in the ozone layer—that blanket of three-oxygen “ozone” molecules that protect us from much of the sun’s ultraviolet radiation—researchers worried about pollutants destroying those highly reactive molecules. The British scientists’ 1985 announcement confirmed that daunting reality.
Technically a substantial thinning of the ozone layer, the ozone “hole” has been opening every spring since the 1970s, the scientists reported. Their data, collected at the Halley Research Station in Antarctica, suggested that CFCs were to blame. That’s because atmospheric conditions during the cold, dark, Antarctic winters were building stockpiles of CFCs over the South Pole [National Geographic].
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The rainmakers of the 21st century may be armed with powerful lasers. New research suggests that zapping clouds with laser beams could trigger the formation of condensation droplets that would fall to the ground as rain. But while the study, published in Nature Photonics, raises the tantalizing hope of bringing on-demand rain to parched regions, some experts argue the technique is unlikely to ever be practical.
For more than 50 years, efforts to try to artificially induce rain have concentrated on ‘cloud seeding’ — scattering small particles of silver iodide into the air to act as ‘condensation nuclei’, or centres around which rain droplets can grow. “The problem is, it’s still not clear that cloud seeding works efficiently,” says optical physicist Jérôme Kasparian at the University of Geneva, Switzerland. “There are also worries about how safe adding silver iodide particles into the air is for the environment” [Nature News].
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If you thought the toxic bubbling lakes of asphalt DISCOVER covered on Friday were impressive, you ought to see what’s under the sea just off the California coast: giant volcanoes made from the same stuff we use to pave our roads.
Lead author David Valentine and his colleagues first found these asphalt volcanoes in 2007 when they sent submersible robots to explore peculiar formations 700 feet below the surface. Now, in a study in Nature Geoscience, the team has published its findings and its images of the extinct volcanoes. Valentine says the formations are six stories high, and spread out farther than a football field. “If I could convert all the asphalt in the largest volcano to gasoline, it would be enough to fuel my Honda Civic for about half a billion miles” [National Geographic], he says.
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Six days after ash from Iceland’s volcano paralyzed European airspace, aviation experts and academics are arguing over whether the entire mess could have been avoided.
Ash from Iceland’s Eyjafjallajokull volcano started to spread across North European skies last week, grounding thousands of domestic and long-haul flights and causing an estimated $1 billion in losses. Today the European Union attempted to get the continent moving again and reopened certain routes, giving millions of stranded passengers a chance to head home and throwing a lifeline to airlines that were hemorrhaging an estimated $250 million a day.
However, this grounding of flights drew sharp rebuke from Giovanni Bisignani, director general of the International Air Transport Association (IATA), who argued that the entire mess could have been avoided had the airlines focused on facts and figures on actual damage caused to jet engines by volcanic ash, saying: “Europe was using a theoretical mathematical approach and this is not what you need. We needed some test flights to go into the atmosphere and assess the level of ashes and take decisions” [Reuters]. Unsurprisingly, the European Union’s transit officials have replied that they’re not willing to compromise on passenger safety.
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The bottom of the sea is a strange and marvelous frontier, as we were reminded last week by the discovery of the first known animals to live without oxygen. Today a team of British researchers say their undersea robotic explorers have found something new down in the depths of the Caribbean Sea: the deepest hydrothermal vents ever seen.
The black smokers, named for how they spew out an iron sulfide compound that’s black, sit 3.1 miles deep in the Cayman Trough in the Caribbean [FoxNews]. They beat out the previous record holders, which were located 2.6 miles below the surface in the middle of the Atlantic Ocean. As the National Oceanography Centre team sailed across the sea in its research vessel, the James Cook, the scientists deployed their robot explorers down to the inhospitable depths. One, called Autosub6000, mapped the seafloor while another, HyBIS, carried high-resolution cameras to capture these images.
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The “young sun paradox” just won’t go away. For decades, scientists like Carl Sagan have tried to resolve this mystery of the early solar system—how the newborn Earth stayed warm enough to keep liquid water—but it continues to bob and weave around an answer. In the journal Nature, a team led by Minik Rosing proposes an alternate solution to the leading theory, which relies on the greenhouse effect hypothesis. But don’t expect the debate to end here.
The problem is this: The young Earth received much less heat from the sun. Four billion years ago, a lower solar luminosity should have left Earth’s oceans frozen over, but there is ample evidence in the Earth’s geological record that there was liquid water — and life — on the planet at the time [Space.com]. So what gives? The traditional explanation going back to the 1970s has been that a powerful greenhouse effect, far stronger than the one we experience today, kept the Earth basked in enough warmth to keep water sloshing around the planet’s surface as a liquid and not packed in solid ice. In 1972, Sagan and colleague George Mullen wrote that such an effect would have required intense carbon dioxide concentrations in the atmosphere during that period, the Archaen.
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When small earthquakes rumbled beneath northern Texas in 2008 and again in 2009, scientists were puzzled. While they expect to see seismic activity in active zones like Haiti, Chile, and Turkey, where disasters have already struck this year, the area around Fort Worth, Texas sees only rare and tiny seismic activity. Now, some Texas seismologists are arguing that techniques used in conjunction with natural gas exploration provide a plausible explanation for what’s going on.
North Texas sits atop the Barnett Shale, one of the several giant layers of shale in the United States believed to hold a truly massive amount of natural gas. The U.S. Geological Survey estimates that 200 trillion cubic feet of natural gas may reside in shales nationwide [USA Today]. The reason these giant deposits have remained largely untapped, however, is that shale isn’t particularly porous, and so extracting it requires drillers to fracture the rock in multiple places.
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The magnitude 8.8 earthquake that rocked Chile on February 27th didn’t just move the Earth’s axis, thereby shortening the day by 1.26 microseconds, but it also caused entire cities to shift their geographical location.
Studying precise GPS images of the area struck by the quake, a team led by earth scientist Mike Bevis discovered that the Chilean city of Concepción had moved 10 feet to the west. The epicenter of the quake was 71 miles northeast of Concepción, which is Chile’s second largest city.
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In the aftermath of Haiti’s devastating earthquake, nervous citizens can be forgiven for wondering where the next Big One will hit. Major quakes strike with alarming regularity: Earthquakes of magnitude 7 or greater occur approximately 18 times a year worldwide. They usually originate near faults where tectonic plates —tremendous fragments of the earth’s crust—collide or push above or below each other.
Geologists suspect that Haiti’s destructive quake resulted from 250 years of seismic stress that has been building up between the North American and Caribbean tectonic plates. In fact, a group of U.S. geologists presented a study in the Dominican Republic (which shares the island of Hispaniola with Haiti) in 2008 saying that the region was at risk of an earthquake potentially even bigger than last week’s magnitude 7.0 quake. Part of their presentation is particularly chilling in light of what would happen less than two years later: “This means that the level of built-up stress and energy in the earth could one day be released resulting in an earthquake measuring 7.2 or more on the Richter Scale. This would be an event of catastrophic proportions in a city [Port-au-Prince] with loose building codes, and an abundance of shanty-towns built in ravines and other undesirable locations.”
Earthquakes are still impossible to predict with precision; in the words of one of the geologists who predicted the Haiti quake, “It could have been the next day, it could have been 10 years, it could have been 100… This is not an exact science.” But researchers have identified a handful of seismic zones around the globe that are storing up especial amounts of stress and are particularly hazardous. Browse through the gallery for a world tour of the planet’s most seismically vulnerable regions.
By Aline Reynolds
Image: USGS
Groundwater levels around the country have been sinking as wells for drinking water and irrigation pull water out of aquifers faster than they can naturally recharge. Now, using gravity-measuring satellites, NASA and California researchers have documented the extent of water loss in California’s Central Valley, and the results aren’t good.
The measurements show the amount of water lost in the two main Central Valley river basins within the past six years could almost fill the nation’s largest reservoir, Lake Mead in Nevada [AP]. The total is about 30 cubic kilometer; one cubic km contains more than 264 billion gallons of water.
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Twitter: Bane of employers … but friend of science?
At a scientific meet-up in California this week, researchers with the U.S. Geological Survey proposed that the 140-character micro-blogging site could help to speed up responses to earthquakes. “Why would such a system work?” asked Paul Earle, a geologist at the USGS, at the American Geophysical Union fall meeting Monday. “Because people like to tweet after an earthquake” [Wired.com].
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For a geologist, “fast” still means thousands and thousands of years. But in a new study in Nature scientists argue that the modern Mediterranean Sea filled with water in a geologic blink of an eye. A torrential flood of water that moved 1,000 times faster than the Amazon River replenished the once-dry sea in perhaps just a few months, the researchers say.
History shows that the Strait of Gibraltar has often determined access to (and thus control of) the Mediterranean, and that goes for the water itself, too. Around 5.6 million years ago the Mediterranean Sea almost completely evaporated when it became disconnected from the Atlantic Ocean. This was due to uplift of the Strait of Gibraltar by tectonic activity, combined with a drop in sea level [New Scientist]. When the strait sank just enough to reach the water level 5.3 million years ago, ocean waters began to cascade through and fill the sea.
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In a bit of unexpected climate related good news—not for us, of course—some shell-building ocean dwellers like blue crabs, shrimp, and lobsters may actually benefit from increased ocean acidification. This surprising finding seems to be good news for lobster lovers, but researchers note that the ongoing acidification still appears to spell trouble for many marine creatures.
Scientists now think that acidifying oceans may allow these select crustaceans to build stronger shells and exoskeletons, instead of making them more brittle. Carbon dioxide (CO2)—the notorious byproduct of fossil fuel burning—dissolves in the ocean. That makes the ocean more acidic. It also reduces the number of so-called carbonate ions in seawater, and these ions are among the primary materials that sea creatures use to build their calcium carbonate shells and skeletons [LiveScience]. Justin Ries, a coauthor on the new study, speculates that these bottom dwellers are somehow better able to manipulate CO2 ions to build their shells, even though fewer CO2 ions are available to them in an acidic environment. However, exactly how they accomplish this is unknown.
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A super-colossal volcanic eruption rocked Italy 39,000 years ago, and troubling signs at the site, now known as Campi Flegrei, have many scientists wondering when the next big one will hit. To probe the issue, so to speak, the Campi Flegrei Deep Drilling Project will drill nearly 2.5 miles down into the collapsed volcanic crater to find out if another blast is on the horizon. Though the researchers on this particular project point out that any risk is small, it will begin amid debate about whether such endeavours are safe, given the unknowns of a volcano’s interior. A few say drilling might even trigger a major eruption [New Scientist]. However, scientists on the project say this isn’t likely, as their drills won’t dig deep enough to set off an eruption.
Campi Flegrei isn’t well known because it lacks a volcanic cone, but it dwarfs Mount Vesuvius. All of Naples sits within its caldera, an eight-mile-wide collapsed area of land formed by the eruption 39,000 years ago. A similar volcanic eruption would leave large parts of Europe buried under ash, say scientists, however smaller eruptions occur every few centuries; the last eruption was in 1538. The researchers hope that by drilling into the volcano, they’ll learn if another smaller eruption is imminent. They hope to locate fracture zones and magma pools that could only be guessed at without drilling. This could show exactly where magma might ascend and collect prior to an eruption. Meanwhile, rock samples could be tested under high stresses in the lab to help model the ground deformation prior to eruption [New Scientist]. The caldera’s center has risen about 10 feet since the 1960s, which has lit a fire under the researchers since a similar rise proceeded a series of intense eruptions 4,000 years ago.
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In 2005, the earth cracked open in Ethiopia. Two volcanic eruptions shook the desert, and a 35-mile-long rift opened in the land, measuring 20 feet wide in some places. Now a new study adds weight to the argument that the opening of this crack marks the first step in the formation of a new sea that may eventually separate East Africa from the rest of the continent. Says lead researcher Atalay Ayele: “The ocean’s formation is happening slowly, likely to take a few million years. It will stretch from the Afar depression (straddling Ethiopia, Eritrea and Djibouti) down to Mozambique” [ABC News].
The study, to be published in the journal Geophysical Research Letters, explains that the seismic movements observed in Ethiopia are very similar to the changes wrought by faults and fissures on the seafloor, where the processes that move tectonic plates usually begin.
Seismic data from 2005 shows that the rift opened in a matter of days. Dabbahu, a volcano at the northern end of the rift, erupted first, then magma pushed up through the middle of the rift area and began “unzipping” the rift in both directions, the researchers explained in a statement today. “We know that seafloor ridges are created by a similar intrusion of magma into a rift, but we never knew that a huge length of the ridge could break open at once like this” [LiveScience], says study coauthor Cindy Ebinger.
The active volcanic region in Ethiopia’s Afar desert sits at the boundary of the African and Arabian tectonic plates, which have been gradually spreading apart for millions years; the new study shows that large-scale seismic events can speed up that process. The gradual separation has already formed the 186-mile Afar depression and the Red Sea. The thinking is that the Red Sea will eventually pour into the new sea in a million years or so [LiveScience].
Related Content:
DISCOVER: Meet the New Continent: East Africa
DISCOVER: The Thrill-Seeker’s Travel Guide points tourists towards the Afar desert
80beats: Tremors Point to a Stressed-Out Stretch of the San Andreas Fault
80beats: Armed With Data, Scientists Still Mystified by Antarctica’s Hidden Mountains
80beats: Ancient Continental Collisions May Have Provided Air to Breathe
Image: University of Rochester
