Don’t be alarmed, but on a remote island in Scotland the sheep are shrinking.
Instead of gradually increasing in size as expected due to evolution, the average weight of the wild sheep has decreased as average temperatures heat up. The discovery shows that a species’ response to global warming can be unpredictable, and can be based on multiple factors. According to a study published in Science, warmer and wetter winters have made it easier for smaller sheep to survive the hard months and go on to bear offspring, thus passing these “small” genes onto the next generation of sheep.
Since 1985, the average weight of the wild Soay sheep living on the island of Hirta has decreased by about 5 percent. Due to global warming, the winters on the Scottish isles are becoming becoming shorter and milder. That makes food more abundant and allows some of the smaller, more vulnerable and younger sheep to survive. Then they go on to have offspring that tend to be small themselves — and have a better chance of survival because of the increasingly mild winters. “The environmental and evolutionary processes are intertwined. There’s still natural selection, but it’s not leaving as big a signature as it used to. There’s still a disadvantage to being small, but not as much” [Time], says lead researcher Tim Coulson.
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In a 219-212 vote, the House of Representatives passed on Friday a climate bill designed to decrease U.S. dependence on oil and create “green” jobs. It’s now up to the Senate to pass or veto the American Clean Energy and Security Act, which also proposes a cap-and-trade system to impose historic limits on U.S. greenhouse gas emissions.
The bill has been tweaked since it was approved in May by the House Energy and Commerce Committee, and it remains unclear how much progress the Senate will make on the bill. In it, U.S. emissions of carbon dioxide and other greenhouse gases would be reduced 17 percent by 2020 from 2005 levels. That is less ambitious than the 20 percent initially sought, but slightly more aggressive than the approximately 15 percent Obama proposed. The legislation sets further pollution reduction goals — 42 percent by 2030 and 83 percent by 2050, with the latter just slightly higher than Obama suggested [Reuters]. The bill also speeds up the administration of $346 million in stimulus funds for the development and implementation of energy efficient technology.
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Global warming is expected to cause such alarming climate disruptions that talk of hurricanes and heat waves can overshadow another drastic process at work: Burning fossil fuels and otherwise producing excess carbon dioxide makes oceans and other bodies of water more acidic, as the water absorbs the gas. This acidification can change a fish’s physiology in ways that were previously unpredicted and could affect the fish’s survival, according to a study in Science.
Scientists raised groups of white sea bass in water of varying concentrations of carbon dioxide. They found that the fish in the most highly acidified water had the largest rock-shaped ear bones, known in biology parlance at otoliths. That contradicts what the researchers had hypothesized: The ear structure in fish, known as an otolith, is made up of minerals. Scientists knew that increasing carbon dioxide in the oceans — absorbed from the atmosphere — is making the sea more acidic, which can dissolve and weaken shells. They wondered if it also would reduce the size of the otoliths [Los Angeles Times]. Instead, the ear bones of fish growing in the tank with six times as much carbon dioxide than normal were 15 to 17 percent larger than normal. An water with a CO2 concentration about 3.5 times higher than current levels yielded fish with otoliths that were 7 to 9 percent larger than those raised in water with today’s carbon dioxide levels. That’s the CO2 level predicted by the year 2100.
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The state of Louisiana is losing its coastal wetlands to the Gulf of Mexico, and a new study suggests that conservationists won’t be able to turn the tide. If engineers don’t divert sediment-rich waters from the Mississippi River to help replenish a sinking river delta, about 10 percent of [the] state will slip beneath the waves by the end of this century. However, even if the engineers do try to abate the subsidence, the Mississippi doesn’t carry enough sediment to offset more than a small fraction of that loss, a new analysis suggests [Science News].
Before American settlers subdued the Mississippi and its tributaries, the river periodically overflowed its banks and spilled muddy water, thick with sediment, into surrounding wetlands. But the new study found that the Mississippi and Atchafalaya rivers today carry only half the sediment they did a century ago — between 400 million and 500 million tons a year then, compared with just 205 million tons today. The rest is now captured by more than 40,000 dams and reservoirs that have been built on rivers and streams that flow into the main channels [The Times-Picayune].
So even if Louisiana officials embark on an all-out campaign to restore the marshes through controlled levee breaks and diversion projects that bring back river water, it wouldn’t be enough to save the land–especially since sea levels are rising due to global warming. “We conclude that significant drowning is inevitable” [The Guardian], the study’s authors wrote.
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Curious how much carbon the atmosphere contains at this moment? Look no further than a giant “carbon counter” first switched on yesterday morning near New York City’s Pennsylvania Station. The 70-foot-tall screen, lit by digital low-energy LED, displays in real time the amount of greenhouse gases present in the atmosphere–and therefore gives some indication of how much trouble humanity is facing from global warming.
People outside of New York, don’t despair: The constantly scrolling numbers can be viewed at the project’s Web site as well. The numbers shown are based on measurements developed at the Massachusetts Institute of Technology and include all the long-lasting greenhouse gases in the 1997 Kyoto Protocol, which was established at the United Nations Framework Convention on Climate change [Bloomberg].
The clock, which is illuminated 24 hours a day, is also environmentally friendly. It uses low-risk carbon credits to offset its energy use, while illuminating digital numbers with 40,960 low-energy light-emitting diodes [Bloomberg]. The counter is a project Deutsche Asset Management, a branch of Deutsche Bank that invests in industries that mitigate or adapt to climate change.
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A new report from the federal government loudly makes the point that global warming is already happening, and not just in the remote reaches of Alaska. “This report stresses that climate change has immediate and local impacts,” said Jane Lubchenco, administrator of the National Oceanic and Atmospheric Administration. “It literally affects people in their backyards” [Science News]. The report details the impacts to U.S. infrastructure like roads, sewage plants, and offshore oil drilling operations, and also takes note of the expected effects on sundry industries, from fishing in the northwest to maple sugar production in New England.
The report was prepared by the United States Global Change Research Program, which includes work from 13 federal agencies and the White House; the group is required to report once a decade on the state of the global environment. While the document contains little new science on global warming, experts say it’s a valuable synthesis of previous findings. “It’s not a document for scientists. It’s not even a document for policymakers,” said Katharine Hayhoe, a geosciences professor … and one of 28 report co-authors. “It’s a document for every individual citizen who wants to know why they should care about climate change” [Scientific American].
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Leaving the rainforest of the Amazon standing has obvious benefits to the environment, as the living forests absorb and store carbon dioxide that would otherwise contribute to global warming. But cutting down the forests has been assumed to be the only route to economic development for the local people, as it provides work in the timber industry and then clears the way for farming and cattle raising. Now, a new study has found that deforestation brings only short-term and temporary economic benefits, in what researchers call a boom-and-bust cycle.
The researchers say the boom is probably due to a number of factors, including better roads and therefore better access to healthcare and schools. For a short while, the community benefits from the natural resources of the forest, and makes money off the timber and the farms that are set up in the cleared lands. But the soil is rapidly degraded making farming and cattle ranching unsustainable. “A lot of that land ends up being abandoned” [New Scientist], says study coauthor Robert Ewers.
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Scientists have long known that coral reefs are being threatened by disease, global warming and other factors. Now a new study shows that that majority of Caribbean reefs have, in fact, been “flattened” in the past four decades, as ornate branched corals have died out and been replaced by flatter, fast-growing “weedy” species. Most of the reefs have lost all the intricate, tree-like corals that until the 1970s provided sanctuary for unique reef fish and other creatures, as well as protecting coastlines by sapping the energy of waves [New Scientist], according to the report, published in the journal Proceedings of the Royal Society B.
The coral reefs that were initially the most complex have almost been completely eliminated, says the researchers, who analysed changes in the structure of reefs using 500 surveys across 200 reefs conducted between 1969 and 2008. They found that 75 per cent of the reefs are now largely flat, compared with 20 per cent in the 1970s [ScienceDaily]. That’s bad news for sea life and storm defenses, says study coauthor Lorenzo Alvarez-Filip: “For many organisms, the complex structure of reefs provides refuge from predators…. This drastic loss of architectural complexity is clearly driving substantial declines in biodiversity, which will in turn affect coastal fishing communities” [ScienceDaily].
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It’s not just humans who can take part in combating global warming–cows can play a role, too. Scientists say that the methane belched up by cows is a significant source of the greenhouse gas, and are searching for ways to reduce these burps. The digestive bacteria in the cows’ stomach produces the methane, which is the second-most significant gas (behind carbon dioxide) driving global warming. While methane is much less prevalent in the atmosphere than carbon dioxide, it traps heat 20 times more efficiently than carbon dioxide.
Researchers are examining a variety of tactics, including breeding or genetically engineering cows that belch less, or adjusting the bacterial mix in cows’ stomachs. But altering the cows’ feed has shown the most promise thus far. Since January, cows at 15 farms across Vermont have had their grain feed adjusted to include more plants like alfalfa and flaxseed — substances that, unlike corn or soy, mimic the spring grasses that the animals evolved long ago to eat. As of the last reading in mid-May, the methane output of [one test] herd had dropped 18 percent. Meanwhile, milk production has held its own [The New York Times].
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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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A radar survey conducted between 2004 and 2008 by Japanese, Chinese, and British scientists reveals how the ice on Antarctica grew, and what the land looks like beneath the ice. At the center of the continent, a nearly two-mile-thick slab of ice has clung to Antarctica’s rocky surface for 14 million years; this is the first time scientists have gotten a virtual glimpse beneath the sheet’s surface.
The topography beneath the ice is mountainous, with peaks and valleys like the European Alps, according the study published Nature. Scientists say that 34 million years ago, small glaciers expanded from the mountaintops and shifted to carve out the terrain. To collect the data, scientists drove huge trains of caterpillar tractors in tight lines over Dome A, a plateau of ice at the heart of Antarctica. The tractors carried radars that pinged down through the ice and sent back profiles of the frozen rock landscape below [New Scientist]. Scientists knew the velocity of the radar’s radio waves, so they calculated the depth of the ice by timing how long it took the waves to hit the rock and come back to the surface.
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As global warming gradually melts away the sea ice in the Arctic Ocean, the oil and gas deposits buried in that inaccessible region are becoming a lot less theoretical to the five northern nations with claims to those riches. “For better or worse, limited exploration prospects in the rest of the world combined with technological advances make the Arctic increasingly attractive for development,” said Paul Berkman, … who specialises in the politics of the Arctic [The Guardian]. Now, a new study has estimated how much oil and gas may lie beneath the Arctic seabed, declaring that it contains about 30 percent of the planet’s undiscovered natural gas reserves and 13 percent of its undiscovered oil.
Researchers estimate that the Arctic holds about about 83 billion barrels of undiscovered oil, but say that’s not enough to challenge the dominance of the oil-rich Persian Gulf states. Meanwhile, the researchers say that the Arctic’s estimated 1,550 trillion cubic feet of natural gas is concentrated in marine territory claimed by Russia, ensuring that Russia will continue to be the world’s largest producer of gas. “These findings suggest that in the future the … pre-eminence of Russian strategic control of gas resources in particular is likely to be accentuated and extended,” said Donald L. Gautier, lead author of the study [AP].
Russia has not been shy about pressing its claim to the polar region: In 2007 two Russian civilian mini-submarines descended to the seabed to collect geological and water samples and drop a titanium canister containing the Russian flag [AP]. The other four northernmost nations — Canada, the United States, Norway, and Denmark (via Greenland) — have also sought some jurisdiction over parts of the Arctic.
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Fierce dust storms this spring have stained Colorado’s snow-covered peaks with brown, red, and pink dust, and state officials point out that this isn’t just a change in scenery. The darker snow is absorbing more radiation from the sun and is therefore melting faster and sooner than it normally would, which is upsetting the careful water rationing that defines life in the American West. Twelve dust storms barreled into the southern Rockies from the deserts of Arizona, Utah and New Mexico so far this year…. That, coupled with unseasonably warm temperatures, has sped up the runoff here, swelling rivers to near flood stage, threatening to make reservoirs overflow and fueling fears that there will not be enough water left for late-summer crops [Los Angeles Times].
In Colorado, melting snow accounts for about 80 percent of the water that flows through rivers and ends up in the state’s lakes and reservoirs. Colorado water engineer Scott Brinton explains that the early snowmelt could spell disaster for thousands of farmers and ranchers in the region who depend on slowly melting snow to provide water flows over the dry summer months…. “Those people who were relying on the mountain snowpack are going to have difficulty later in the year…. There’s not a whole lot we can do about it,” Brinton said. “We’re telling people, ‘You’ll be getting your water early this year, so use it while it lasts’” [Greenwire]. But scientists note that this may not be just a year of freak storms, it may be a harbinger of things to come.
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President Obama proposed new fuel efficiency standards today, establishing the first nationwide regulation for greenhouse gases [Washington Post]. The proposal is centered around the strictest plan ever for increasing fuel standards for passenger vehicles, sharply raising pressure on struggling automakers to make more efficient cars and trucks [Reuters]. Under the plan, cars would be required to reach an average efficiency of 35.5 miles per gallon (mpg) by 2016—four years earlier than the deadline imposed by the 2007 energy bill. Light trucks would be required to reach 30 mpg.
The new rules would pose a challenge for car manufacturers: the White House estimates the current average efficiency to be 25 mpg. The new standards would resolve the spat between California and auto manufacturers over implementing the state’s emissions regulations [ClimateWire]. In return for the strict national rules, California will drop its plans to impose strict state-wide standards for fuel efficiency, which had been bitterly resisted by both carmakers and President George Bush. In practice California’s rules tend to override milder national regulations, as it is cheaper to follow them than to produce different vehicles [The Economist].
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If global warming melts the West Antarctic ice sheet, the thick slab of ice that covers an area the size of Texas, the situation for coastal dwellers around the world may not be as dire as previously estimated. A new study, which has sparked some debate, suggests that the water released by West Antarctica’s melting glaciers would raise sea levels by about 10 feet, not the 15 to 20 feet that had previously been predicted.
While the results sound like good news, Antarctic experts and the study’s lead author, Jonathan L. Bamber of the Bristol Glaciology Center in England, agreed that the odds of a disruptive rise in seas over the next century or so from the buildup of greenhouse gases remained serious enough to warrant the world’s attention [The New York Times]. They also note that some regions would also experience a larger surge in sea levels than others. “Sea level rise is not uniform across the world’s oceans, partly as a result of disruptions to the Earth’s gravity field,” explained Professor Bamber. “It turns out that the maximum increase in sea level rise is centred at a latitude of about 40 degrees along the Atlantic and Pacific seaboards of North America.” This would include cities such as San Francisco and New York [BBC News].
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