Scientists track sea ice in the Arctic as it grows to a maximum extent through the winter and shrinks back in the summer to its minimum extent in September each year. This year’s minimum sea ice extent – the smallest area of ice for the year – reached 1.77 million square miles (4.59 million square km). That tied with 2008 and 2010 as the sixth lowest sea ice minimum since consistent satellite records began 40 years ago.
Researchers at NSIDC noted that the estimate is preliminary, and it is still possible (but not likely) that changing winds could push the ice extent lower.
According to NASA’s Earth Observatory:
Arctic sea ice follows seasonal patterns of growth and decay. It thickens and spreads during the fall and winter and thins and shrinks during the spring and summer. But in recent decades, increasing temperatures have led to significant decreases in summer and winter sea ice extents. The decline in Arctic ice cover will ultimately affect the planet’s weather patterns and the circulation of the oceans.
Claire Parkinson is a climate change senior scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. She said in a statement:
This year’s minimum is relatively high compared to the record low extent we saw in 2012, but it is still low compared to what it used to be in the 1970s, 1980s and even the 1990s.
Bottom line: On September 19 and 23, 2018, Arctic sea ice extent dropped to 1.77 million square miles (4.59 million square km) – tied for the 6th lowest minimum in the satellite record.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.