Today’s Image of the Day from NASA Earth Observatory features a map that shows the extent of sea ice in the Arctic as it reached its annual minimum on September 16, 2021.
According to scientists at the National Snow and Ice Data Center and NASA, the summertime extent is the twelfth lowest in the satellite record.
The annual minimum of sea ice measured 4.72 million square kilometers, or 1.82 million square miles, which is higher than recent years. The sea ice extent of 2020 was the second lowest on record at 3.74 million square kilometers.
Even as the planet as a whole was warmer in 2021, less sea ice melted. Record heat struck North America and Eurasia, but conditions stayed generally cold farther north.
Regional variations in weather and sea ice are expected, explained Walt Meier, a sea ice researcher at the National Snow and Ice Data Center.
“We don’t expect sea ice to be lower every year, just like we don’t expect temperatures to be warmer everywhere on Earth every year even with global warming,” said Meier.
“There does appear to be a fair amount of ice in the Beaufort and Chukchi Seas that seems to have gotten quite thin, but there just wasn’t quite enough energy through the summer to melt it out completely.”
Image Credit: NASA Earth Observatory