A drilling rig looms behind a barn in Tioga County, Pa. Scott Detrow/StateImpact Pennsylvania hide caption

itoggle caption Scott Detrow/StateImpact Pennsylvania

Key provisions of the Kyoto Protocol expire in December of 2012, and experts say there's no real global framework in place to replace the treaty that was supposed to be the first step toward ambitious actions on climate change. Above, a coal-fired power plant in eastern China. China is now the leading carbon dioxide emitter in the world. AFP/Getty Images hide caption

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Researchers at the window testing facility at Lawrence Berkeley National Laboratory are developing nanocrystal technology. When activated by a small electrical current, it would allow light but not heat through. Courtesy Lawrence Berkeley National Laboratory hide caption

itoggle caption Courtesy Lawrence Berkeley National Laboratory

The U.S. is second only to China in emitting gases that cause global warming. Above, the smoke stacks at American Electric Power's Mountaineer power plant in West Virginia. Saul Loeb/AFP/Getty Images hide caption

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A man prepares an aye-aye, a rare type of lemur found only on the island of Madagascar, for dinner. These primates are an important source of iron and protein despite being critically endangered. Christopher Golden hide caption

itoggle caption Christopher Golden

Sikh pilgrims stream into the Golden Temple in Amritsar, India, on Nov. 10. Devout Sikhs from all over India and the world come to Amritsar by the tens of thousands every day — adding to an already sizable carbon footprint. So city and temple officials have joined an environmental group to learn how to incorporate environmentally friendly practices. Narinder Nanu/AFP/Getty Images hide caption

itoggle caption Narinder Nanu/AFP/Getty Images

Nathan Phillips looks at methane data plotted on a map of Boston streets on Nov. 17. Data from a mobile methane "sniffer" and a GPS show a real-time display of the gas levels in Google Earth. The orange spike in the center of the screen, on St. Paul Street, indicates methane levels about two or three times above normal levels, Phillips says. Robin Lubbock/WBUR hide caption

itoggle caption Robin Lubbock/WBUR

A Nissan Leaf charges at a station in Portland, Ore., that can recharge an electric car in 30 minutes. Electric cars could be an integral part of meeting 55-mpg fuel standards by 2025, but many consumers are put off by the vehicles' higher price and what some call "range anxiety." Rick Bowmer/AP hide caption

itoggle caption Rick Bowmer/AP

Workers take a break in front of the cooling towers of a coal-fired power plant in Dadong, Shanxi province, China. At a House hearing on Tuesday, Nisha Biswal defended USAID's programs in China, saying the money goes to efforts that include reducing harmful emissions from the country's power plants. Andy Wong/AP hide caption

itoggle caption Andy Wong/AP

A U.N. climate panel says that we can expect more extreme weather conditions as a result of climate change. Above, people run from a high wave on Nov. 8 in Nice, France, where heavy rain and flooding forced hundreds to evacuate. Vallery Hache/AFP/Getty Images hide caption

itoggle caption Vallery Hache/AFP/Getty Images