For over 20 years NASA has been tracking the global surface topography of the ocean to understand the important role it plays in our daily lives. Climate change is causing our ocean to warm and glaciers to melt, resulting in sea level rise. Since 1880, the global sea level has risen 8 inches; by 2100, it is projected to rise another 1 to 4 feet. More about sea level: http://climate.nasa.gov/vital-signs/sea-level/ http://sealevel.nasa.gov More 'NASA's Earth Minute' videos: http://climate.nasa.gov