A team of researchers has come up with a simple plan to halt global warming: All we need to do is turn both the Sahara and the Australian outback into vast, shady forests.
While that might sound so ambitious as to be absurd, the climate scientists say the project would be no more expensive or technologically challenging than some of the other geoengineering schemes that are currently under discussion. And researcher Leonard Ornstein says it would certainly get results. Ornstein says that if most of the Sahara and Australian outback were planted with fast-growing trees like eucalyptus, the forests could draw down about 8 billion tons of carbon a year–nearly as much as people emit from burning fossil fuels and forests today. As the forests matured, they could continue taking up this much carbon for decades [ScienceNOW Daily News].
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In one week, the Interior Department has issued two bold new rules that reverse decisions on mining and old-growth forests that were made during the Bush administration. In the first ruling, Interior Secretary Ken Salazar on Monday called for a two-year “timeout” on new mining claims on nearly 1 million acres near Grand Canyon National Park in northern Arizona [Los Angeles Times]. That directive overrides the Bush-era decision to open land near the park to uranium mining claims.
The moratorium on new mining claims near the Grand Canyon will give the Interior Department time to study the environmental effects of mining in that area; the department then has the option of banning mining there for 20 years. Grand Canyon Superintendent Steve Martin has said previously that he was concerned that uranium could get into the watershed and affect the fish in the Colorado River at the bottom of the gorge — and the bald eagles, California condors and bighorn sheep that depend on the canyon’s seeps and springs [Los Angeles Times].
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As of tomorrow, 101 years will have passed since the Tunguska Event, the mysterious explosion that flattened 800 square miles of Siberian forest. Just in time for the anniversary researchers have come up with yet another explanation for what may have caused the baffling blast. Previously, researchers best hypothesis was that a meteor struck the forest, but scientific expeditions failed to turn up an impact crater or any fragments of rock. The new hypothesis, which will be published in the journal Geophysical Research Letters, suggests that the Earth was hit by the icy core of a comet, which exploded in the atmosphere.
Researchers say that a comet strike would have released huge volumes of water vapour at very high altitude, creating highly reflective clouds that may explain why the sky was lit up for days after the collision, with people as far away as London saying that they could read newspapers outdoors at midnight, the scientists said [The Independent]. In an unusual twist, the evidence for the new theory comes from studies of the water vapor exhaust created by space shuttle launches.
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The seeds that twirl down from maple trees every spring can fly as far as a mile, with each wing-shaped seed spinning like a whirligig on the air. Studies have shown that the seed’s whirling, called auto-rotation, gives it extra lift, but why this occurs has never been explained. It took an aerospace engineer, David Lentink of the Wagenigen University in the Netherlands, to figure it out [The New York Times].
Lentink and his colleagues first studied how a model of a maple seed moved in a tank of oil, and then filmed a real seed falling through a smoke-filled wind tunnel, which allowed them to observe the air currents around the seed. The images the team obtained showed that a swirling maple seed generates a tornado-like vortex that sits atop the front leading edge as the “helicopter” spins slowly to the ground. This leading edge vortex lowers the air pressure over the upper surface of the maple seed, effectively sucking the wing upward to oppose gravity [Live Science].
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A landowner in Indonesia may soon find it more profitable to sell carbon credits from untouched forest than to clear the land for agriculture, according to new research. As a case study, the researchers looked at 8.2 million acres that are slated to become plantations in Kalimantan, the Indonesian region of the island of Borneo. The researchers found that paying to conserve the forest was more valuable than plantations as long as poorer nations could earn between $10 and $33 for each tonne of CO2 saved. Currently a credit representing a tonne of CO2 sells for about $20 in the European Union, which has the world’s largest greenhouse gas trading system [The New York Times].
Since forests act like sponges for carbon dioxide, the principal greenhouse gas driving global warming, they can play a role in carbon credit markets that are used in international climate treaties. Industries that can’t cut their emissions enough pay landowners to leave their forests standing, so the trees can suck up carbon and offset the industrial emissions. What’s more, researchers say that such systems could also be a roundabout way to protect endangered species. The 800 proposed plantations that were studied contain 40 of the region’s 46 threatened mammals including orangutans and pygmy elephants [AP].
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Using a fancy piece of chemistry equipment to study the chemical composition of wine, European researchers have one-upped the sophisticated palates of wine connoisseurs. The researchers used ultra high resolution mass spectrometry to sort through all the chemical compounds present in wines that had been aged in oak barrels, and found that for each wine, they could determine which French forest the oak was cut from. No other approach – analytical or sensory – has been able to significantly discriminate wines according to the species or the origin of the oak used for the barrels before, they say [Chemistry World].
The findings could prove useful to wine connoisseurs and historians, the researchers said, concluding that their findings produced “chemical representations of the way such noble nectar can shape, on the (tongue) of the wine taster, some of the outlines of the scene of its birth” [AP]. Similar analyses could also be used to detect wine fraud, the researchers noted.
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Seven grassroots activists who fought powerful polluting industries and often stood up to intimidation are now receiving rewards and recognition: They’re winners of the Goldman Environmental Prize, sometimes called the environmental Nobel Prize. Each year winners are chosen from the six inhabited continents: Africa, Asia, Europe, Islands and Island Nations, North America, and South and Central America [USA Today]. Each winner receives a $150,000 purse.
The winner from North America, Maria Gunnoe, took her stand against coal mining companies in Appalachia, where companies commonly blast the tops of mountains apart to expose hard-to-reach coal seams, and dump the debris in the valleys. “I never even knew I was an environmentalist,” Gunnoe, who lives in southwestern West Virginia, said with a chuckle. Though raised to mind her own business, she was also taught to fight when attacked. That’s how she sees the destruction of her gardens and orchard…. Gunnoe’s home sits below a valley fill and has been flooded with coal waste seven times since 2000 [AP].
Gunroe says she has received numerous threats from miners angered by her opposition the coal industry; after she helped convince a judge in 2007 to shut down an operator working without a legal permit, a “wanted” poster printed with her face hung in local stores until the FBI demanded its removal [Mercury News].
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In the latest development in the ongoing debate about why some leaves turn bright red in the fall, a new study suggests that the color is a signal to insect pests to stay away. Harvard biologist Marco Archetti sought to prove the theory, first put forth in 2001 by the late evolutionary biologist William Hamilton, that the red pigments, or anthocyanins, serve as a plant’s chemical defense. Archetti studied aphids’ survival rates in wild apple trees, which turn more red, compared with farmed trees, which produce more green and yellow leaves. He found that aphids don’t show up as frequently on apple trees that turn red in the fall [ScienceNews]. He also reports in the study, published in Proceedings of the Royal Society B, that once spring came, young aphids who had fed on red trees in the fall were less likely to grow to maturity than aphids placed in the green or yellow trees.
Archetti chose aphids for the study because fall is their mating season: They leave their summer plants to find a good tree for mating and egg laying. Aphids can damage trees in two ways, especially when the new generation hatches in the spring. The insects steal the sap and also spread diseases with their piercing mouthparts that end up as entomological dirty needles. So trees would do well to dodge aphids [ScienceNews]. To test whether the red signals a threat to the insects, Archetti placed nesting aphids in both red- and green-leaved apple trees in the fall of 2007, and found that the next spring, 60 percent of those in green trees had survived, compared with 29 percent in red trees. The reason behind this disparity is unclear, but Archetti’s and other studies suggest that the red leaves either have toxic chemical defenses or hold fewer nutrients for young aphids [ScienceNow Daily News].
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Researchers have found that droughts kill pine trees faster when temperatures are higher, a piece of information that bodes ill for forests in a warmer world. A new study examined the effect of dry conditions and temperature on the pinion pine, a hardy evergreen that lives in the American Southwest, and found that “together, drought and temperature can kind of provide a double whammy,” said David Breshears, a researcher involved in the experiment [Reno Gazette Journal].
Researchers could isolate the impact of heat due to the unusual environment where the experiment took place. The study was conducted in Biosphere 2, a glass and steel laboratory that includes recreations of the planet’s savannas, deserts, oceans and forests…. Half the pinions studied were kept in normal temperatures, the others in an environment 7 degrees warmer. Some trees in each group were then deprived of water to simulate droughts common in the past [AP]. Trees subjected to higher temperatures died five times faster than the other trees, suggesting that even short droughts could produce widespread tree mortality in a warmer climate [AP]. The study was published in the Proceedings of the National Academy of Sciences.
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If all goes as planned, the Orbiting Carbon Observatory (OCO) will be blasted into space early tomorrow morning, and will become the first spacecraft dedicated to studying carbon dioxide, the leading greenhouse gas driving global warming. Researchers say the satellite will answer long-standing questions. Thirty billion tons of carbon dioxide waft into the air from the burning of fossil fuels each year. About half stays in the air. The other half disappears. Where it all goes, nobody quite knows…. The new data could help improve climate models and the understanding of the “carbon sinks,” like oceans and forests, that absorb much of the carbon dioxide [The New York Times].
Annual variations in the amount of carbon dioxide in the atmosphere suggest that the carbon sinks may “fill up” some years and be unable to absorb more of the gas. These fluctuations make it hard to predict future conditions, says principal investigator David Crisp, of NASA: “People are asking us to predict how much the climate will change over the next 50 years…. How can I tell you how much CO2-induced climate change there’s going to be if I don’t know how much CO2 there’s going to be in the atmosphere?” he says. Even if it were possible to predict how much CO2 humans will put into the atmosphere, “that’s still only half the puzzle,” he says. “I still need to know how much is going to be absorbed by the earth” [Technology Review].
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Over the past 30 years, the salamanders that used to thrive in the tropical cloud forests of Mexico and Guatemala have been disappearing, and until now no one had even noticed that the stealthy amphibians may be spiraling downward towards extinction. Back in the 1970s, biologist David Wake studied salamanders in the San Marcos region of western Guatemala, and he recently returned to the region to survey the current salamander population and compare it to his previous data. What he found shocked him, Wake says. “Cold facts written on a piece of paper don’t convey the impact on my psyche when I went there,” he said. Species that could be seen 10 to 15 times an hour in the 1970s were “completely gone” [National Geographic News]. Studies in Mexico that compared current salamander populations to historical data produced similar results.
Since the 1980s biologists have raised alarms about worldwide declines in amphibians attributed to habitat destruction, disease and climate change, among other menaces [Science News]. Scientists studying dwindling frog populations have focused largely on chytrid, a fast-killing fungus, as the possible culprit, but Wake says that only a few of the salamanders he found on his recent trips showed signs of chytrid fungus. Instead, he blames global warming. Wake says that warming temperatures on the steep, forested slopes of Guatemala’s volcanoes are forcing the salamanders up to higher to less hospitable elevations.
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Trees in the old-growth forests of the American West are dying at an accelerating pace, and researchers say that the early impacts of global warming are probably to blame. The bad news was found in California, the Pacific Northwest, and in the interior Western states. Says study coauthor Phillip van Mantgem: “Tree death rates have more than doubled over the last few decades in old-growth forests across the Western United States.” … The researchers found rising death rates across a wide variety of forest types, at different elevations, in trees of all sizes and among major species, including pine, fir and hemlock [Los Angeles Times].
Van Mantgem says that average temperatures in the West have risen by more than 1 degree Fahrenheit in the last few decades. “While this may not sound like much, it has been enough to reduce winter snowpack, cause earlier snowmelt, and lengthen the summer drought” [Reuters], he says. Droughts make trees more stressed and vulnerable to disease, and warmer temperatures have also allowed the spread of pine beetles and other pests that attack trees. And while the death rate of old trees is increasing, the rate of new trees sprouting and surviving has not risen.
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Three years ago, a controversial study alarmed climate researchers by stating that plants produce methane, a potent greenhouse gas, as part of their normal operations. Those findings went against the standard idea that forests are one of our few buffers against global warming since they absorb and store carbon dioxide; suddenly, scientists began wondering if planting more trees might do more harm than good. But now a new group of researchers says it has refuted the 2006 study, although the scientist who did the original work is not backing down from his claims.
In the new study, to be published in the Proceedings of the Royal Society B, researcher Ellen Nisbet first looked at how that earlier study was conducted, and saw that the earlier researchers had put glass chambers over plants growing in the wild and measured how the mix of gases within the chamber changed. Nisbet says that procedure meant that the plants could have absorbed methane from the soil, instead of creating it themselves. Part of her team’s work involved growing several different varieties of plant, including maize and rice, in media that contained no organic material, so eliminating the chances of methane being formed through decay in soil. They found during these experiments, conducted in closed chambers, that the plants produced no methane at all [BBC News].
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Forest scientists have come to a surprising conclusion regarding old growth forests and their majestic, mature trees: They’re not just relaxing in their arboreal old age, but are still actively taking in carbon dioxide from the atmosphere. The new study suggests that protecting old growth forests may be just as important as planting new trees in efforts to reduce carbon dioxide levels and fight global warming.
Previously, researchers believed that only young, fast-growing trees absorbed enough carbon dioxide to be considered significant “carbon sinks.” Old, crowded forests don’t allow for much new growth: The only new growth occurred in the small spaces that opened up when large old trees died and decomposed, releasing their accumulated carbon. The forests at large were therefore considered to be carbon neutral, and accounted as such in climate models [Nature News]. But the new study shows that the slow but continuous growth of old trees means that they continue to suck up more carbon than they release.
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After running a batch of 300-year-old Stradivarius violins through a sophisticated medical scanner, researchers say they may have figured out why the aged instruments are revered for their tone, clarity, and power: The wood used for the ancient violins shows a more consistent density than that found in modern violins, and researchers argue that this difference may affect how vibrations travel through the wood.
In particular, the old wood shows less variation in density within growth rings, researchers say. Tree rings are comprised of a lighter, spongier portion that is produced during rapid spring growth and a darker, denser portion produced later in the year; in the Stradivarius wood these differences are less pronounced. Other researchers who have studied the activity of the Sun have pointed to a mini-Ice Age that occurred in the early 1700s. Experts say that this reduced solar activity, called the Maunder Minimum, could have hampered the regular growth of trees [BBC News].
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