NASA | Arctic Sea Ice Reaches 2015 Minimum Extent

In 2015, the Arctic sea ice reached its fourth lowest extent on record, measuring 1.7 million square miles. This was 699,000 square miles below the 30-year average from 1981 to 2010, a difference comparable to the size of Alaska. Scientists have observed a consistent decline in sea ice coverage over the past three decades, with 10 record minimums occurring in the last 11 years. Not only is the thin seasonal ice melting, but the thicker, multi-year ice is also becoming less resilient. This trend suggests that future years may experience even larger ice melts.

What was the Arctic's minimum ice extent on September 11th, 2015?

• 2.5 million square miles

• 1.7 million square miles

• 3.0 million square miles

• 1.2 million square miles

Since when have scientists been using satellites to monitor Arctic sea ice?

• 1989

• 1979

• 1999

• 1969

How much lower is this year's minimum ice extent compared to the 30-year average?

• 1,000,000 square miles

• 699,000 square miles

• 300,000 square miles

• 500,000 square miles

What trend have scientists observed in Arctic sea ice coverage over the past three decades?

• Declining ice coverage

• Increasing ice coverage

• Stable ice coverage

• Fluctuating ice coverage

What type of ice is becoming less resilient according to the measurements?

• Only thick multi-year ice

• Only thin seasonal ice

• Both thin seasonal and thick multi-year ice

• Neither type of ice