Shrinking Ice Forces National Geographic Maps To Make Biggest Change Since The Soviet Union Collapse

National Geographic's maps have changed dramatically. But it's not because of redrawn national boundaries; it's a result of climate change. Shrinking Arctic ice has led the company to adjust its maps in the latest edition of National Geographic Atlas of the World.

The 10th edition of the atlas includes revisions due to shrinking ice caps, but it could quickly become outdated based on the latest satellite imagery and data. A new blog post following President Barack Obama's climate change plan last week explained why National Geographic made the changes. As NatGeo explains on its blog, global warming has led to the ocean getting warmer and that leads to the shrinking of Arctic ice. Climate change also has led to record glacial ice melt. Glaciers have lost an average thickness of 1.6 feet to 3.2 feet each year, according to a new study.

On the National Geographic maps, the white area represents multiyear ice, while the ice that melts and freezes each season is depicted as a line. Cartographers used 30 years of data collected by NASA satellites and yearly data collected by the National Snow and Ice Data Center up to 2012. That year saw a record low in average Arctic sea ice minimum in September. NASA satellites observed a minimum if 3.61 million square kilometers (1.4 square miles) in 2012. That number increased in 2013 and 2014 -- to 5.1 million square kilometers (2 million square miles) and 5.02 million square kilometers (1.9 million square miles), respectively -- but that minimum is much lower than in previous years. The rate of change is -13.3 percent per decade, according to NASA.

"The end of Arctic summer is still several weeks away, and it's still too early to say if another record will be broken," Juan Jose Valdes, National Geographic geographer, said. "But one need only look at the maps derived from satellite imagery to see the impact of global warming."

National Geographic does recognize that the new maps could confuse the public. NASA uses the minimum, recorded in September, to gauge the impact of climate change on Arctic sea ice. An Arctic sea ice map using an average over a number of years could help account for yearly differences.