The time has arrived to start taking a close look at the assorted different Arctic sea ice extent metrics, in order to ascertain their respective maxima for 2025. To begin with here’s Zack Labe’s overview of previous years’ maxima:
It now seems highly likely that 2025’s maximum extent will ultimately prove to be the lowest in the satellite era. The remaining question is when this year’s maximum will occur.
My speculation yesterday that AWI’s flavour of Arctic sea ice extent had already achieved its maximum value for 2025 has been negated today:
The NSIDC 5 day average and JAXA extent metrics are also currently at their maximum levels for the year so far, so let’s wait and see which one is the first to take a downward turn.
On March 22, Arctic sea ice likely reached its maximum extent for the year, at 14.33 million square kilometers, the lowest in the 47-year satellite record. This year’s maximum extent is 1.31 million square kilometers below the 1981 to 2010 average maximum of 15.64 million square kilometers and 80,000 square kilometers below the previous lowest maximum that occurred on March 7, 2017.
After spending several weeks in the unfortunate position of lowest for the date, JAXA/ViSHOP Arctic sea ice extent has just risen above 2015. By a mere 10,000 km²:
Despite the fact that JAXA extent is still rising, AWI extent has potentially already achieved its maximum value for 2025:
Somewhat belatedly, here is the PIOMAS sea ice thickness map for February 28th 2025:
At the end of February Arctic sea ice volume had increased to 19.32 thousand km³, still 2nd lowest for the date in the PIOMAS record:
AWI have also released a new version of their thickness product, incorporating additional data from the two Sentinel 3 satellites. The thickness data for February 28th, looks slightly different:
The New Year began with JAXA/ViSHOP extent lowest for the date in the satellite era, just below 2018 . Since then extent has reduced, and there is now a large gap:
The primary reason for this is the remaining open water in Hudson Bay:
In previous years Hudson Bay has been covered by sea ice by this time of year, but in 2025 a large area remains unfrozen in early January!
Due to the way PIOMAS handles the leap years the last gridded thickness data of 2024 is dated December 30th:
By December 30th Arctic sea ice volume had increased to 13.61 thousand km³, 2nd lowest for the date in the PIOMAS record:
Christmas is coming, and even as we speak Snow White is heading for the geographical North Pole to assist Santa’s little helpers in their annual gift delivery mission:
Santa at the North Pole in August 2016
We’ll start the festive season with a graph of JAXA/ViSHOP extent, which is in a “statistical tie” with 2020 for 2nd lowest for the date in the satellite era:
The Laptev and East Siberian Seas have now refrozen. Consequently Arctic sea ice extent is now increasing more slowly, and JAXA/ViSHOP extent is 3rd lowest for the date in the satellite era:
Note the change in scale from previous months, to allow for easier comparison with the “near real time” CryoSat-2/SMOS merged thickness data from the Alfred Wegener Institute:
The JAXA extent graph is currently not updating, so let’s begin this month with the latest AMSR2 sea ice concentration map from the Alfred Wegener Institute. Click the image to see a ~10 Mb animation of the last four weeks:
Note in particular the restart of export into the East Greenland Sea via the Fram Strait:
and the movement of ice within the Canadian Arctic Archipelago:
The PIOMAS gridded thickness data for September 2024 has been released:
At the beginning of September JAXA/ViSHOP extent was 4th lowest for the date in the satellite era:
For much more detail on sea ice extent for the next few weeks please see the dedicated 2024 minimum thread. However, note that as extent has been flatlining sea ice area is still declining:
The latest AMSR2 sea ice concentration map from the Alfred Wegener Institute reveals that the area of thick ice in the Chukchi Sea has still not melted:
The most recent sea ice age map currently available dates from the beginning of August. Comparison with the concentration map shows that most of the remaining first year ice is highly fragmented, even close to the North Pole:
David Scott Cowper is 82, and his first solo voyage through the Northwest Passage, in the converted lifeboat Mabel E. Holland, began in the Davis Strait in 1986. After spending 3 winters north of the Arctic Circle, Mabel eventually travelled south through the Bering Strait in 1989:
David’s second solo voyage through the Northwest Passage took place from east to west starting in 2003. His purpose built motor vessel, Polar Bound, spent the winter in Cambridge Bay and completed the voyage in the summer of 2004:
For this summer’s east to west voyage David is travelling in Polar Bound once again, this time accompanied by Susannah Broome. They have crossed the North Atlantic from Newcastle and have recently departed from Qaqortoq in the south west of Greenland:
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