Arctic sea ice continued the fast retreat that was observed in July through August 10, followed by a brief slowdown, only to pick up pace again. During the first half of August, the ice primarily retreated in the northern Beaufort Sea and in the East Siberian Sea. The ice also mostly cleared out of the Northwest Passage, whereas ice remained in the Chukchi Sea, along the Northern Sea Route. In the Southern Ocean, sea ice began to expand rapidly after a slow growth from May through July, but remains at the second lowest daily extent as of this post.
Arctic sea ice extent as of August 18 was 5.20 million square kilometers (2.01 million square miles) (Figure 1a). The first week of August continued to have the rapid pace of ice loss observed in July (Figure 1b). However, afterwards the pace slowed for several days but picked up again. Extent approaches 2007 levels, while tracking above the record 2012 minimum. Sea ice extent is currently fourth lowest, behind 2012, 2019, and 2020.
Figure 2b. This plot shows average sea level pressure in the Arctic in millibars from August 1 to 17, 2024. Yellows and reds indicate high air pressure; blues and purples indicate low pressure.Credit: NSIDC courtesy NOAA Earth System Research Laboratory Physical Sciences Laboratory High-resolution image
Figure 3a. This map shows the date of sea ice melt onset in the Arctic for the 2024 melt season. Shades in purple depict early melt, while shades in yellow depict melt later in the season.Credit: J. Strove, NSIDC; data courtesy J. Miller and L. Boisvert, NASA GoddardHigh-resolution image
Figure 4a. This time series shows total sea ice area for 2024, 2023, 2022, 2021, 2011, and the 1991 to 2020 average within the northern route of the Northwest Passage. Data are from the Canadian Ice Service.Credit: S. Howell, Environment and Climate Change CanadaHigh-resolution image
The Northwest Passage (NWP) is a sea route that connects the Atlantic Ocean with the Pacific Ocean through the channels of the Canadian Archipelago. It has been long imagined as a potential future economic backbone for global trade. There are several routes through these channels. In 2007, the northern deepwater route of the NWP, entered from the west through M’Clure Strait, was ice free for the first time during the satellite data record and has been open several years since. As of August 15, the sea ice area in the northern route is currently tracking just above the 2011 record low (Figure 4a). The southern route, known as Amundsen’s Route, is tracking below the 1991 to 2020 average, but above the record low with ice still present in Victoria Strait (Figure 4b). Although ice conditions have been very light in recent years, challenges to navigation still exist. For instance, the processes of Arctic Ocean sea ice export and seasonal first-year ice aging create choke points in the NWP.
