A map depicts temperature changes over the past 20 years, compared to the average between 1901 and 1960. "The period from 2001 to 2011 was warmer than any previous decade in every region," according to the National Climate Assessment.
Wind generators at Pacific Hydro's Cape Bridgewater wind farm in Warrnambool, Australia, in May 2012. Each generator produces roughly enough energy to meet the annual needs of 12,000 households.
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A condemned house in the Ocean Breeze area of New York City's Staten Island. Most homes in the seaside community were inundated by the ocean surge from superstorm Sandy.
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Somali girls line up to receive a hot meal in Mogadishu last year after the worst drought in the Horn of Africa in decades, compounded by war, put millions in danger of starvation.
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