Muir Glacier melt, Alaska pictured at 1891, left, and 2004, right. (Ulysses William O. Field/NASA - Bruce F. Molnia/NASA via ABC News)
Muir Glacier melt, Alaska pictured at 1909, left, and 2004, right. (G.D. Hazard/NASA - Bruce F. Molnia/NASA via ABC News)
Shrinking glacier, Yosemite National Park pictured at 2009, left, and 2014, right. (U.S. National Park Service/NASA via ABC News)
Decker Glacier at Whistler in 2006, left, and 2014, right. (Jason Krupa/USGS via ABC News)
BEFORE: McCarty Glacier melt, Alaska pictured at 1909. (Ulysses Sherman Grant/NASA via ABC News)
AFTER: McCarty Glacier melt, Alaska pictured at 2004. (Bruce F. Molnia/NASA via ABC News)
BEFORE: Toboggan Glacier melt, Alaska pictured at 1909. (Ulysses Sherman Grant/NASA via ABC News)
AFTER: Toboggan Glacier melt, Alaska pictured at 2000. (Bruce F. Molnia/NASA via ABC News)
BEFORE: Pedersen Glacier melt, Alaska pictured at 1917. (Louis H. Pedersen/NASA via ABC News)
AFTER: Pedersen Glacier melt, Alaska pictured at 2005. (Bruce F. Molnia/NASA via ABC News)
BEFORE: Arapaho Glacier melt, Colorado pictured at 1898. (R. S. Brackett/NASA via ABC News)
AFTER: Arapaho Glacier melt, Colorado pictured at 2003. (Tad Pfeffer/NASA via ABC News)
BEFORE: Decker Glacier at Whistler in 2006. (Jason Krupa/USGS via ABC News)
AFTER: Decker Glacier at Whistler in 2014. (Jason Krupa/USGS via ABC News)