Happening Now: Arctic Sea Ice – On the Decline | Ocean Today

Happening Now: Arctic Sea Ice – On the Decline


Transcript

NARRATOR:

As summer turns to Fall in the Arctic, the ice cover will shrink to its smallest extent for the year. This day is an important day because the measurement taken will be used to analyze the state of the Arctic region and add to the growing body of knowledge of the fundamental changes that are taking place.
 
At 4.41 million square kilometers or 1.79 million square miles, 2015 was the fourth-smallest summer sea ice minimum extent in recorded history. This is 1.87 million square kilometers below the 1981 to 2010 average extent.

This chart shows the disturbing trend over the last thirty years. The sea ice extent at the end of the melt season is on a decline. And not only is the ice extent getting smaller, but the ice is also thinning at an alarming rate. In fact, some computer models project we are on track to see an ice-free summer within 20 years. That’s 40 to 50 years earlier than previously forecast.

One source of heat to the arctic is through warmer ocean currents via the Pacific and Atlantic pathways.  This lateral heat underplates the sea ice, and so the ice melts from below as well as from above.

The more the ice melts, the more ocean surface is exposed that can absorb heat from the sun. This warms the water and the region even further, melting even more ice. This scenario has direct consequences: A warmer Arctic accelerates the melting of Greenland’s ice sheet. This ice sheet is currently 1.9 miles thick and, if melted, contains enough ice to raise global sea levels by about 25 feet.

Less sea ice and warmer ocean water also affect atmospheric patterns, like the jet stream, and may lead to more extreme summer and winter weather events in the U.S., Europe, and Asia. So, what happens in the Arctic doesn’t stay in the Arctic. The disappearance of summer sea ice cover is one of the most visible warning signs of severe climate change and will have consequences that are felt all over the world.