- The Arctic: Warm surface water accelerates sea-ice melting in the Barents Sea
- The Antarctic: Declining sea-ice cover on the Bellingshausen Sea
- Research: Polaris 1, Tara Polar Station’s first drift expedition, has now begun. On a new, dedicated page on the Sea Ice Portal, you can find live data, background information and updates on this ambitious overwintering project.
Extreme heat over Europe and in the ocean
For those of us living in Europe, June 2026 will go down in history as an extremely hot summer month. This is due in part to the extreme heat wave in the fourth week of June, which produced record-breaking highs of 41 to 44 degrees Celsius in many parts of Central and Western Europe. In addition, the ocean in the tropical, subtropical and temperate latitudes warmed to such an extent in June 2026 that, on 21 June, the mean sea surface temperature climbed to 21 degrees Celsius, beating out the past record daily highs from June 2023 and 2024 by 0.1 degree Celsius (for more detailed information, please consult the Copernicus Climate Change Service).
The Arctic: Warm surface water accelerates sea-ice melting in the Barents Sea
When the ocean beyond the polar regions absorbs so much heat from the atmosphere, it can affect sea-ice development in the Arctic and Antarctic. Indications of precisely this phenomenon could be seen in June 2026 in the Arctic Barents Sea. There, the surface water was on average roughly 1.5 to 3 degrees Celsius warmer than the long-term mean for the years 1971 – 2000. In May, the sea-surface temperature anomalies in the region were only 0.5 to 2.5 degrees Celsius, which tells us that the sea surface in the North Atlantic warmed further in the course of June (Figure 1). Satellites also registered unusually high sea surface temperatures in the European North Sea, in the Baltic, in the western North Sea, in the southern Greenland Sea, in parts of the Labrador Sea, and in certain coastal regions of the Bering Sea. In contrast, the sea surface was cooler than in the reference period in the Arctic coastal regions of Siberia, in Hudson Bay, and in the Canadian Arctic.
Figure 1: Mean Arctic sea-surface temperature anomalies in June 2026 (l.) and May 2026 (r.). In the map for June, the exceptionally high water temperatures in the Barents Sea, Baltic, and European North Sea are clearly recognisable. Given that the sea-surface temperature anomalies in May were much less pronounced, it can be assumed that the extreme heat wave over Central and Western Europe intensified the warming of the North Atlantic.
In June, the unusually high sea-surface temperatures in the European North Sea and the Barents Sea likely drove sea-ice melting between the archipelagos Svalbard and Franz Josef Land (Figure 2). Compared to the long-term mean, there were conspicuously large areas of open water in the region. The same is true for Hudson Bay and the waters between northeast Baffin Island and western Greenland (Figure 3). Satellites detected more sea ice than the long-term mean in the Bering Strait, Beaufort Sea, and in the marginal ice zones of Fram Strait and Davis Strait.
In the course of the month, the sea-ice extent dropped from 11.35 million square kilometres (1 June 2026) to 9.07 million square kilometres (30 June 2026) – a seasonal decline of more than 2 million square kilometres. The monthly mean sea-ice extent was 10.44 million square kilometres, the eighth-lowest monthly mean in the June time series. Nevertheless, the figure for June 2026 was above the trend line and roughly matched the mean June extent in 2025 (Figure 4).
Figure 2: Mean sea-ice concentration in the Arctic in June 2026.
Figure 3: Difference in the mean position of the ice margin in June 2026, compared to the long-term mean for the years 2003 – 2014. Regions marked in blue had more Arctic sea ice in the sixth month of 2026 than in the reference period; those marked in red had less.
Figure 4: In June 2026, the mean sea-ice extent was above the trend line and nearly matched the monthly mean value for June 2025.
“In the Arctic, we’re currently seeing a number of parallels to the sea-ice development in the early summer of 2025. For instance, the sea-ice melting is proceeding at the same pace. But if we take a look at the map of mean air temperature anomalies, it would seem that the melting was somewhat delayed in the central Canadian and East Siberian Arctic in June 2026. On average, the air masses there were significantly cooler compared to the long-term mean,” says Dr Klaus Grosfeld, a climate researcher at the AWI and co-initiator of the Sea Ice Portal (Figure 5).
Figure 5: Mean Arctic temperature anomalies in June 2026, compared to the reference period June 1971 – 2000. Whereas the air masses over the Arctic marginal zones were warmer than in the reference period 1971 – 2000, there was a substantial cluster of colder air masses over the central Canadian and East Siberian Arctic. Source: Copernicus ERA5 data
The Antarctic: Declining sea-ice cover on the Bellingshausen Sea
In the Antarctic, the sea-ice extent climbed as expected in June – from 11.07 to 13.97 million square kilometres. With a mean sea-ice extent of 12.48 million square kilometres, June 2026 came in higher than the monthly means for the four previous years. However, the sea-ice extent was once again more than 500,000 square kilometres below the trend line for the month of June. In other words, the sea-ice situation in the Antarctic remains tense. The hoped-for rebound after the record-low year 2023 has now slowed (Figure 6).
Figure 6: Time series of mean Antarctic sea-ice extent for the month of June. The monthly mean value was well below the sky blue trend line for a fifth consecutive time. The upward trend following the record-low year 2023 lost momentum from June 2025 to June 2026.
Sea-ice formation and distribution in the Antarctic are subject to powerful natural fluctuations, as a comparison of the mean positions of the ice margin in June shows (Figure 7). Local winds, temperatures and currents have a major influence on which regions the sea surface freezes over in and where the young sea ice drifts to. In this regard, one trend is becoming more and more apparent: in the Bellingshausen Sea, the sea-ice cover is gradually declining. According to press reports, the region was “missing” roughly 650,000 square kilometres of pack ice at the beginning of June – an area somewhat larger than France (632,702 square kilometres).
If we compare the development of the mean sea-ice concentration in June from 2010 to the present, it becomes apparent how much less new sea ice is now formed in the Bellingshausen Sea (Figure 8). In fact, in the first week of June 2026 the level of sea-ice cover briefly declined once again – even though winter had long since begun in the Southern Hemisphere (Video 1).
Figure 7: Mean sea-ice concentration and mean position of the ice margin in the Antarctic in June 2026 (left) in comparison to the long-term mean and the June mean from 2025, 2024 and 2023. The comparison underscores the natural variability in Antarctic sea-ice distribution. However, it can also clearly be seen that there was substantially less sea ice off the coast of West Antarctica than in the record-low year 2023.
Figure 8: Mean sea-ice concentration in the Antarctic in June 2026 (left) and in June 2010, 2015, 2020 and 2025. The comparison illustrates the gradually declining sea-ice concentration in the Bellingshausen Sea.
Video 1: Changes in Antarctic sea-ice concentration from 1 to 30 June 2026. As the sequence shows, the amount of sea-ice cover in the Bellingshausen Sea shrank briefly in the first week of June, followed by the extensive formation of new sea ice.
The fact that less new sea ice than the long-term mean formed off the west coast of Antarctica in June could be due in part to the air temperatures. Our map of mean air temperature anomalies over the Antarctic shows a heat dome over West Antarctica, the Antarctic Peninsula and the Weddell Sea, while temperatures over East Antarctica tended to lie below the long-term mean (Figure 10). In contrast, the map of mean sea-surface temperature anomalies shows no irregularities (Figure 11).
Figure 9: Mean Antarctic temperature anomalies in June 2026, compared to the reference period June 1971 – 2000.
Figure 10: Mean Antarctic sea-surface temperature anomalies in June 2026, compared to the reference period June 1971 – 2000.
Tara Polar Station: First of ten planned drift expeditions through the Central Arctic begins
On Sunday 19 July, one of the most ambitious international Arctic research projects of the 21st century will begin in the French port city Lorient – Tara Polar Station will depart from its home port, embarking on the first of ten planned ship-based and drift expeditions through the sea ice of the Arctic Ocean. Since each expedition with the innovatively formed ship will take at least a year, the station’s research agenda currently stretches over two decades – from 2026 to 2046.
“At the heart of the project is the question of how climate change is affecting the Arctic ecosystem, and how relevant these effects will be for the global climate, particularly the interplay of atmosphere, sea ice, ocean and ecosystems,” says AWI sea-ice physicist Dr Marcel Nicolaus.
“To that end, we’ve worked together with experts from more than 30 partner institutes to develop a long-term observational strategy: over the next two decades, Tara Polar Station’s repeated drift missions will help to establish an unparalleled dataset on the evolving Arctic. Rather than gathering snapshots, our goal is to continuously document changes in the Arctic system over extended periods, which will in turn help us to gauge their effects on the global climate system,” he adds.
Figure 11: Tara Polar Station represents a dedicated research platform for extended drift expeditions in the Arctic sea ice. Its oval, rounded hull allows it to withstand the pressure of compressing sea ice, as any pressures cause it to ‘pop’ upwards, out of harm’s way. reinforced aluminium hull offers stability under harsh Arctic conditions. Outside the pack ice, the station can manoeuvre at speeds of up to 9 knots – but during normal operations, it drifts along the Arctic Ocean with the sea ice. Photo: Maéva Bardy – Fondation Tara Ocean
Figure 12: AWI experts Julia Regnery (r.) and Marcel Nicolaus (l.) are part of the small research crew that will work on board Tara Polar Station during its first drift expedition. Chemist Julia Regnery will be on board for the first leg of the expedition, including an overwintering; sea-ice physicist Marcel Nicolaus will take over for her in the spring of 2027, serving on the second leg, which will continue into the summer. Photo: Marcel Nicolaus/Alfred Wegener Institute
Marcel Nicolaus is one of many AWI experts who were involved in the scientific planning for the first Tara expedition. In the spring and summer of 2027, he’ll also spend several weeks on board Tara Polar Station. “A major focus of the AWI’s contribution is on sea-ice physics. During the drift, we’ll use our under-ice robot ANN to take readings below the sea ice in a radius of up to 300 metres around the ship, collect multiple ice cores, and regularly measure the ice and snow thickness, as well as other physical properties of the sea ice,” he explains.
Whereas Marcel Nicolaus is slated to join the second leg of the drift mission, his AWI colleague Dr Julia Regnery will soon be packing her bags: in mid-August, she’ll go on board in the port of Kirkenes, Norway and be responsible for taking all scheduled meteorological readings during the first leg of the mission – both on the ship and on the Arctic pack ice.
During the overwintering from September 2026 to April 2027, there will only be six scientists, the captain and first officer, an engineer, doctor, cook and a journalist on board. In summer, they’ll be joined by further researchers, expanding the expedition team to 18 members.
Don’t miss out: Follow Tara Polar Station’s Polaris 1 expedition on the Sea Ice Portal
The Sea Ice Portal will provide extensive coverage of Tara Polar Station’s first drift expedition (Polaris 1). You’ll find live data from the ice, weekly updates, and in-depth monthly reports from Julia Regnery and Marcel Nicolaus on our exclusive Tara expedition page. The page also features extensive background information in German and English. We also highly recommend following Marcel Nicolaus and Julia Regnery on Instagram. On their channel @2imEis, the two AWI experts are already sharing impressions of how they’re preparing for the expedition – with more content to follow.
Further, we’ll regularly report on their research work and life on board the unconventional research ship as part of our sea-ice updates. But it will take a few more weeks before Tara Polar Station reaches the Arctic pack ice. If everything goes according to plan, the station will rendezvous with a Chinese research icebreaker in the Russian Laptev Sea on 10 September 2026. The icebreaker will clear a path through the ice and accompany the station for roughly a day. After that, Julia Regnery and her colleagues will be on their own and begin taking a closer look at the Arctic Ocean, its sea ice, and the countless marine organisms that depend on it.
Recommended reading for your summer holiday: The new European State of the Climate Report is here
To round out this monthly update, we have some recommended reading for your summer holiday. The European State of the Climate Report for 2025, jointly published by the Copernicus Climate Change Service and the World Meteorological Organization (WMO), was recently released. Experts from the Sea Ice Portal contributed facts, figures and data on the development of the Arctic sea ice in 2025. The English-language report is available in both an online version and as a downloadable PDF. Happy reading!
Figure 13: Cover of the European State of the Climate Report for 2025. Released annually, the report is jointly published by the Copernicus Climate Change Service and the World Meteorological Organization (WMO). AWI sea-ice experts contributed to the chapter on sea-ice development in the Arctic. Image: European State of the Climate Report 2025
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