BREAKING THE ICE: The Arctic Ocean will be ice-free during summer within a decade, a team of polar explorers announced Thursday. That means the North Pole will be an open ocean, allowing ships free passage, and the top of the world will appear blue instead of white from space. While winter ice will remain in the Arctic for hundreds of years, an absence of summer ice will spell doom for polar bears, walruses and other animals that depend on rafts of floating sea ice to hunt seals, fish and oysters. The Catlin Arctic Survey team, which recently spent three months in the Arctic, measured the thickness of ice and determined most is first-year ice around 6 feet deep, most of which will melt next summer. The region traditionally holds older, multiyear ice that doesn't melt as quickly, and the explorers say this is some of the clearest evidence yet that manmade climate change is rapidly melting the Arctic. And in related ice-melting news, Swiss researchers have found that Alpine glaciers are releasing toxic pollutants as they melt — things like dioxins and DDT that were frozen into the ice before they were outlawed years ago — adding another danger to the quick meltdown of decades-old ice. (Sources: Associated Press, Reuters, BBC NewsIndependent)

TAKING A LEAK: Methane is a minor greenhouse gas in terms of quantity and longevity, but it packs a much stronger punch than carbon dioxide, trapping up to 25 times more heat from the sun. And, as the NY Times reports today, it's being pointlessly emitted by countless natural gas producers via leaky equipment. A natural-gas storage tank might look innocent to the naked eye, but a glance through an infrared lens shows columns of methane — the main ingredient in natural gas — wafting skyward from some unseen leak. In addition to saving money and energy for gas producers around the world, fixing these leaks could also help ward off, or at least soften, climate change. Roughly 3 trillion cubic feet of methane leak into the air annually, the Times reports, with Russia and the United States leading the way. As natural gas becomes a more and more popular alternative to carbon-heavier fuels like coal and oil, fixing such leaks could make a world of difference. (Source: New York Times)

WOLF HUNTS: Wolf hunting has been shut down in the Montana backcountry adjacent to Yellowstone National Park, after human hunters killed nine wolves there in recent weeks, including several from a pack that has become familiar to tourists. Despite the uptick in wolf kills, however, Montana wildlife officials are keeping the statewide kill quota at 75, and maintain that the planned wolf harvest poses no threat to the overall population. 2009 marks the first wolf hunts in the Lower 48 states since gray wolves first became an endangered species in 1974; populations in Montana and Idaho were removed from the list earlier this year. Montana has about 550 wolves, and its current quota will allow hunters to kill 15 percent of its overall population. Idaho's quota of 220 wolves equals roughly 26 percent of that state's total population. (Sources: AP, Helena Independent Record)

BUNNIES FOR BIOFUEL: Sweden is facing both a growing plague of invasive rabbits as well as a growing demand for alternative energy, so the country is doing what any red-blooded descendants of Vikings would do: burning bunnies for biofuel. Stray rabbits are being shot, frozen and shipped to a heating plant, where they're incinerated for fuel. It's a grisly idea, but the Swedes' patience is running thin — wild and stray pet rabbits are running amok, ravaging city parks and other vegetation, and culling programs are only making a dent. Sweden has already gone down this particular rabbit hole, using slaughterhouse trimmings for biogas to run taxicabs, and U.S. companies are also using pork and chicken fat to make biofuels. Since the rabbit power is still only a meager slice of Sweden's energy portfolio, however, it's also tossing dead cats, deer, cows and horses into the fire. (Source: Scientific American)

RADIOACTIVE RABBITS: If we're using bunnies for energy anyway, why not skip straight ahead to radioactive rabbit power? The U.S. Department of Energy recently conducted helicopter surveys above the Hanford nuclear reservation in Washington state — where two-thirds of U.S. plutonium was made from World War II until the 1980s — and its radiation detectors found fields full of radioactive rabbit droppings, surprisingly in an area that had never been used to make plutonium. The rabbits are believed to have burrowed through other areas that were contaminated, then carried cesium and strontium, which emit gamma rays, to new areas via their digestive tracts. They're not the only animals to be contaminated — fish, badgers, mice and bees have also tested positive for radiation — but researchers are worried that they're apparently spreading the radiation to previously uncontaminated places. (Source: NY Times)

FAMILY TREE: Plants are able to recognize their siblings, researchers from the University of Delaware have discovered, shedding new light on the bizarre sensing systems of plants — as well as their family dynamics. Plants grown from the same seeds can recognize the chemical signatures secreted by one another's roots into the surrounding soil, and treat their relatives differently than they would a stranger. Siblings growing next to each other "play nice," the researchers report, declining to send out the competitive roots they might use to attack a nonrelative's personal space. Unrelated plants grown side-by-side are often shorter, since they must dedicate more of their energy to the underground root battle, while siblings tend to be taller and have shallower roots. (Source: ScienceDaily)

GATOR CHOMP: Just because you eat region-appropriate food doesn't mean you're eating local, the Atlantic points out. Oysters are a "local" food in Savannah because they're traditionally caught and eaten there, but ordering them at a River Street restaurant could easily provide you with a plate full of farm-raised oysters from New England. Similarly, going to New England for an authentic apple pie could nonetheless yield a New Zealand-based dessert. One of the last bastions of true local food, however, can be found on the bayou: alligator. If you go to Thibodaux, La., and order gator, you're getting Louisiana gator. While the locality of well-established, popular and mass-produced foods like chicken, beef, oysters and apples can be hard to ensure, writes the Atlantic's Dave Thier, more eccentric cuisine like gator is still a reliably regional choice. And a novel technique for raising wild-reared gator eggs on a farm, employed by Insta-Gator Ranch, is helping make gator an even more sustainable food. (Source: Atlantic via Huffington Post)

Russell McLendon

Want to receive the day's eco-news in your inbox? Click here to sign up for the Daily Briefing newsletter.

Photo (polar bear): U.S. National Oceanic and Atmospheric Administration

Photo (gray wolf): U.S. Fish and Wildlife Service

Photo (rabbits): NOAA

Photo (alligator): U.S. Geological Survey

Russell McLendon ( @russmclendon ) writes about humans and other wildlife.