Arctic Ice Reaches a Low High

ENVIRONMENT

The winter ice covering the Arctic Ocean has reached its annual peak, but the extent of sea ice this winter is smaller than it has been since scientists began keeping consistent satellite records. (New York Times graphic)

Use our Polar Regions MapMaker Kit to plot the receding sea ice.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

This map shows the extent of Arctic sea ice for February 25, 2015. The extent was 14.54 million square kilometers (5.61 million square miles). The orange line shows the 1981 to 2010 median extent for the same day. (The black cross indicates the geographic North Pole.) Map by National Snow and Ice Data Center

This map shows the extent of Arctic sea ice for February 25, 2015. The extent was 14.54 million square kilometers (5.61 million square miles). The orange line shows the 1981 to 2010 median extent for the same day. (The black cross indicates the geographic North Pole.)
Map by National Snow and Ice Data Center

Discussion Ideas

  • Scientists recently tracked the extent of Arctic sea ice. What is sea ice? How is it different from regular ice?

 

  • New data show Arctic sea ice has reached its lowest “winter maximum” on record. What is a winter maximum? In what months do you think sea ice experiences a winter maximum?
    • A winter maximum is also just what it sounds like. Sea ice grows and reaches its maximum extent during cold Arctic and Antarctic winters.
    • The months when sea ice reaches a winter maximum depends on what hemisphere you’re in.
This chart displays the winter maximum of Arctic sea ice since 1981. Graphic by National Snow and Ice Data Center

This chart displays the winter maximum of Arctic sea ice since 1981.
Graphic by National Snow and Ice Data Center

 

Decades of scientific research has documented the phenomenon of Arctic shrinkage. Arctic shrinkage includes the melting of the Greenland ice sheet, warmer temperatures, and a loss of sea ice. Map by National Geographic

Decades of scientific research has documented the phenomenon of Arctic shrinkage. Arctic shrinkage includes the melting of the Greenland ice sheet, warmer temperatures, and a loss of sea ice.
Map by National Geographic

  • Look at our great map about the slow withdrawal of Arctic sea ice. The map, however, focuses not on “winter maximums,” but on “summer minimums.” What is a summer minimum?
    • The summer minimum is when, warmed by the summer sun, sea ice recedes to its lowest point. Summer minimums are increasing—meaning less ice—with some experts predicting an ice-free Arctic Ocean by 2030.

 

  • The NY Times graphic reports that “Summer minimums . . . can have a greater effect on the global climate than winter maximums.” Why? Take a look at the top of our “Twilight of the Arctic Ice” map for some help.
    • A climate “feedback loop” contributes to a greater loss of sea ice. According to NASA scientist Walt Meier, “During the relatively sunny summers, the dark ocean surface of ice-free parts of the Arctic absorbs much more solar energy than highly reflective sea ice. This can create a warming feedback loop when the ocean absorbs sunlight and heats the air above it.”
    • The ice that melts during summer minimum is older, thicker ice. “When you lose summer ice you aren’t really just losing it for that year, you’re also losing some ice from many years ago,” he said. “That makes it harder for things to go back towards normal.”

 

TEACHERS’ TOOLKIT

New York Times: Arctic Ice Reaches a Low Winter Maximum

National Snow and Ice Data Center: Arctic sea ice reaches lowest maximum extent on record

Nat Geo: Polar Regions MapMaker Kit

National Snow and Ice Data Center: All About Sea Ice

Nat Geo: Twilight of the Arctic Ice

2 responses to “Arctic Ice Reaches a Low High

  1. Pingback: 11 Things We Learned This Week | Nat Geo Education Blog·

  2. Pingback: 11 Things We Learned This Week | Nat Geo Education Blog·

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