HOME FOR THE HOLIDAY: Today is World Environment Day, an annual United Nations event that began in 1972 with the goal of sparking environmental awareness, attention and action. That challenge may be easier this year with the release of Home, "a high-budget documentary to save the planet from Yann Arthus-Bertrand," according to AFP. I can understand your confusion, but Home isn't saving the planet from Yann Arthus-Bertrand; he's the director. The eco-doc is being released worldwide today, mostly for free, and can be viewed online here. It was shot over 217 days in 54 countries, providing 488 hours of footage that took nearly three years to produce into the final film. With sweeping, cinematic views of Earth shot from a helicopter, Home focuses first on "the miracle of life on Earth," Arthus-Bertrand tells AFP, with the ultimate message being, "It's too late to be a pessimist." (Sources: UNEP, Agence France-Presse)

TO THE BATCAVE! Thanks to a mysterious, fast-spreading fungus, America's bats now face a danger worse than any themed supervillain. Experts warned Congress Thursday that "white-nose syndrome" represents the most serious threat to wildlife in a century, and could spread nationwide within years. The disease, which attacks bats in their caves, was first noticed in upstate New York in March 2007 and has since expanded to 65 caves in nine Northeastern states, killing up to a million bats. Scientists are worried it could soon spread to the Southeast and Midwest, home to some of the most endangered bat populations. In addition to killing off bat species, the little-understood fungus is taking away a major consumer of mosquitoes and other insects that destroy crops, forests and carry disease. (Sources: Associated Press, New Jersey Star-Ledger, U.S. Fish and Wildlife Service)

SICK AND TIRED? It sounds like a great idea — recycle ground-up tires to cushion the surfaces of playgrounds and sports fields, keeping the rubber from the waste stream while also preventing children's injuries. The EPA has endorsed the practice for years, and the Obamas even recently used recycled tire shreds for their new White House playground. But now EPA scientists are raising concerns that we don't know enough about possible health risks from the rubber material, which can contain carcinogens and other chemicals. Although several studies have failed to find any dangers, the scientists suggested in an internal memo that the EPA take a neutral stance until more research can be conducted. (Source: AP)

GETTING GAS: While the Tennessee Valley Authority appeals a court order to clean up its coal-fired power plants, the embattled public utility is offering an olive branch to some of its environmental critics: a cleaner, more efficient combined-cycle natural gas plant. In January, a federal judge ordered TVA to install more pollution controls on a coal plant in East Tennessee by the end of 2011, which may force the plant to sit idle for up to 20 months while it's brought into compliance. Even though it's appealing that decision, TVA also decided on Thursday to build an 880-megawatt, $820 million natural gas power plant to make up for the lost power generation. (Sources: Chattanooga Times Free PressAP)

THE GOOD CHINA: The United States is seeking a joint pact with China to deal with the two countries' greenhouse gas emissions, U.S. climate enovy Todd Stern said in a speech Thursday to the Center for American Progress. It was the latest of many signs pointing to increasing cooperation between America and China, the world's two top contributors to global warming. Negotiators began holding secret talks months ago, although mandatory limits on emissions are still too touchy a subject to hash out seriously just yet. Rather, the discussions are more likely to focus on technological cooperation, such as improving industrial efficiency, expanding solar power and developing techniques for carbon capture and storage, which is especially attractive to coal-hungry China. The Chinese government further allayed eco-fears Friday morning over its response to the recession by pledging to strictly monitor its economic stimulus package to make sure it doesn't harm the environment. (Sources: Guardian, AP)

GREAT LAKES CZAR: The Obama administration has appointed a Chicago-based environmentalist to manage the daunting cleanup of the Great Lakes, the world's largest group of freshwater lakes and home to 22 percent of the planet's freshwater. Cameron Davis, president of the Alliance for the Great Lakes, was appointed Thursday by EPA Administrator Lisa Jackson to head the $20 billion-plus restoration effort, overseeing about a dozen federal agencies. (Source: AP)

THE BEST MEDICINE: Who knows if humans will have the last laugh, but scientists have determined that we probably didn't have the first. Chimps, orangutans and gorillas all chuckle, and they may have inherited laughter from a shared human ancestor that lived more than 10 million years ago. The researchers tickled 21 great apes as well as three human babies and meticulously analyzed the sounds, tracking similarities among the closely related primate species. While ape laughter sounds different than the human "ha ha" — rapid panting or grunting, for example — each creature's laugh was related, and matched how the animals themselves were related to one another. Another researcher argues that humor may go back even further, claiming that he has recorded rats producing high-pitched chirps in response to play and tickling. (Source: AP)

Russell McLendon

(Photo: AP)

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