Planet Health Report: SEA ICE

Planet Health Report: SEA ICE

What is happening to the ice?

During the winter, the top layer of the ocean near the North Pole freezes solid. Every summer some of this ice melts. But not all of it melts. Some of the ice is so thick it stays frozen all the time, even throughout the summer. However, since 1979, when Earth-observing satellites began watching, the ice remaining at the end of summer has been getting smaller and smaller. At the end of summer 2009, the ice was only two-thirds as large as at the end of the summer of 1979. In August 2012, is was the smallest on record.

Satellite view of Arctic Ocean, sept. 2012, showing sea ice, with yellow outline showing average over last 30 years.

This image from satellite data shows the extent of Arctic sea ice at the end of summer 2012. The yellow outline shows the average end-of-summer sea ice over the past 30 years since satellites began observing. Credit: NASA/Goddard Scientific Visualization Studio

So what? The sea ice is an important part of how ocean currents move heat from the equator to the poles and move the cold water from the poles back to the equator. All life in the ocean depends on this energy circulation. All life on land also depends on life in the oceans.

Sea ice is an important measure of our planet's health.