climate change climate change

The "Sydney Ice Bear" on Friday in Sydney, Australia. The bear was carved by British artist Mark Coreth from a 10-ton block of ice. The public will be welcomed to touch the bear, leaving imprints that will begin the melting process and act as a metaphor for how humans affect the environment. Lisa Maree Williams/Getty Images hide caption

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Lisa Maree Williams/Getty Images

A scientist stands in front of an ice-rich permafrost exposure in the coastal zone of Herschel Island, Yukon Territory, Canada. Ice in the permafrost is melting, contributing to rapid erosion. Michael Fritz/Alfred Wegener Institute hide caption

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Michael Fritz/Alfred Wegener Institute

The exoplanet Corot-7b has a mass five times that of Earth's and is the closest known exoplanet to its host star. The probable temperature on its "day-face" is above 2,000 degrees, but minus 200 degrees on its night face. This artist's impression of the planet comes from the European Southern Observatory and shows how it may look like if it were covered by lava. L. Calcada/ESO hide caption

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L. Calcada/ESO