During a campaign speech at Veterans Memorial Park in Manchester, N.H., Oct. 18, President Obama once again embraced the term "Obamacare" while discussing the Affordable Care Act. Darren McCollester/Getty Images hide caption

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A boat skims through the melting ice in the Ilulissat fiord, on the western coast of Greenland, in 2008. The glacier is the most active in the Northern Hemisphere, producing 10 percent of Greenland's icebergs, or some 20 million tons of ice per day. But experts say the glacier is in bad shape because of climate change. Steen Ulrik Johannessen/AFP/Getty Images hide caption

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A general view of the Aletsch Glacier on April 21, 2007, near Brig, Switzerland, the largest glacier in the Alps. Unseasonably warm weather with temperatures up to 77 degrees Fahrenheit across Switzerland let snow melt, even at Alpine altitudes. Johannes Simon/Getty Images hide caption

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U.S. Marines drive amphibious armored personnel carriers in the Philippines on Oct. 9, as part of the annual joint exercises with Philippine counterparts. Jay Directo/AFP/Getty Images hide caption

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This Sept. 16 image released by NASA shows the amount of summer sea ice in the Arctic, at center in white, and the 1979 to 2000 average extent for the day shown, with the yellow line. Scientists say sea ice in the Arctic shrank to an all-time low of 1.32 million square miles on Sept. 16, smashing old records for the critical climate indicator. NASA/AP hide caption

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President Obama and Republican presidential candidate Mitt Romney first debated Medicare on Oct. 3. Saul Loeb/AFP/Getty Images hide caption

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Veterans applaud at an Oct. 8 campaign event in Swanton, Ohio, for Republican vice presidential candidate Paul Ryan. Health care and unemployment are among veterans' chief concerns this election season, and both the Obama and the Romney campaigns have offered solutions. Mary Altaffer/AP hide caption

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People eat a free community meal at The Center in Lima, Ohio, earlier this year. Although more than 46 million Americans are poor, the issue has gotten little attention in the presidential race. Mario Tama/Getty Images hide caption

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Smoke rises from the stacks of the La Cygne Generating Station coal-fired power plant in La Cygne, Kan. President Obama's regulation of the coal industry has come under fire from his Republican challenger, Mitt Romney. Charlie Riedel/AP hide caption

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Despite some backlash from their political parties, both President Obama and Mitt Romney have made school choice a cornerstone of their efforts for education reform. iStockphoto.com hide caption

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Afghan children run to school on Sept. 24. Whoever takes over as the next U.S. president will have to determine how many troops will remain after the December 2014 deadline to help with long-term security. Jeff Pachoud/AFP/Getty Images hide caption

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President Obama speaks during a campaign event at George Mason University in Fairfax, Va., on Friday. Pablo Martinez Monsivais/AP hide caption

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