Towers carry electrical lines in San Francisco. The electricity grid is a web of power stations, transformers and transmission lines that span the continent. Justin Sullivan/Getty Images hide caption

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A liquefied natural gas tanker arrives at a gas storage station east of Tokyo on April 6, 2009. The shuttering of Japan's nuclear power plants has driven an increased reliance on natural gas and other fossil fuels. AFP/Getty Images hide caption

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Steam rises from the cooling towers of nuclear reactors at Georgia Power's Plant Vogtle in Waynesboro, Ga. The U.S. Nuclear Regulatory Commission approved Southern Co.'s application to begin full construction of the nation's first new nuclear units since 1978 at Plant Vogtle. Mary Ann Chastain/AP hide caption

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Nonnative pythons, like this one, are invading the Florida Everglades. As a top predator, the snakes have crippled the populations of rabbits, raccoons and other animals. Joe Raedle/Getty Images hide caption

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Without a centralized national repository for nuclear waste, the radioactive material is currently being kept at various sites across the country. Above, large concrete canisters, each holding 14 55-gallon drums of waste, are loaded on a truck in 2005 in Richland, Wash., where they were later shipped to a facility in New Mexico. Jeff T. Green/Getty Images hide caption

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Hydraulic fracturing wells have been producing a tremendous amount of natural gas — far more than the current demand. Above, a Cabot Oil & Gas natural gas drill at a fracking site in South Montrose, Pa. Spencer Platt/Getty Images hide caption

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Contractors with SunEdison install more than 1,000 Chinese-made solar panels on top of a Kohl's Department Store in Hamilton Township, N.J., in 2010. Energy generated by the solar system will cut the store's usage, on average, by 25 to 30 percent. Robert Nickelsberg/Getty Images hide caption

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An Indian street dweller prepares food on the streets of Kolkata. A growing number of scientists say that reducing black carbon — mostly soot from burning wood, charcoal and dung — would have an immediate and powerful impact on climate. Deshakalyan Chowdhury/AFP/Getty Images hide caption

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With the skyline of Youngstown, Ohio, in the distance, a brine injection well owned by Northstar Disposal Services LLC is seen in Youngstown on Jan. 4. The company has halted operations at the well, which disposes of brine used in gas and oil drilling, after a series of small earthquakes hit the Youngstown area. Amy Sancetta/AP hide caption

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In a double-blind test by professional violinists, most couldn't determine — by sound alone — which violin was an original Stradivarius and which was a modern instrument. Above, a 1729 Stradivari known as the "Solomon, Ex-Lambert." Don Emmert/AFP/Getty Images hide caption

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A Kemp's ridley sea turtle like this one traveled 4,600 miles across the Atlantic ocean in 2008. After being rehabilitated in Portugal, it is being reintroduced into its native Gulf of Mexico waters on Tuesday. US EPA via flickr hide caption

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The crippled Fukushima Dai-ichi nuclear power station is seen through a bus window on Nov. 12. The four reactors that failed were stabilized this month. David Guttenfelder/AFP/Getty Images hide caption

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Air travel contributes only 2 to 4 percent of carbon dioxide emissions worldwide. A new ruling says airlines flying into and out of European airports will have to pay a price for the carbon dioxide they emit from burning jet fuel. Above, a plane takes off from the Geneva airport last year. Fabrice Coffrini/AFP/Getty Images hide caption

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Nuclear Regulatory Commission Chairman Chairman Gregory Jaczko (center) speaks Wednesday during a meeting of the House Oversight and Government Reform Committee. His fellow commissioners, from bottom left: Kristine Svinicki, William Magwood IV and William Ostendorff. Chip Somodevilla/Getty Images hide caption

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The world's forests act as massive sponges, sucking carbon from the atmosphere. Above, an aerial photo from 2009 shows massive deforestation in the Brazilian state of Para. Antonio Scorza/AFP/Getty Images hide caption

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