The summer of 2012 brought Greenland far more extensive melt than anything observed in the satellite record: in July 2012, surface melt extended over nearly the entire ice sheet. The standardized melt index was nearly double the previous record.

Randy Osborne of LSU and NOAA's Tim Osborn explain how global positioning system (GPS) satellites measure subsidence and sea level rise.

Josh Kent of Louisiana State University gives a simple explanation of how sea level rise from climate change and sinking of the land both contribute to coastal changes.

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