The Polar Retrospective – Arctic heatwaves, a Nunavut road, and sailboats among icebergs
The Polar Retrospective looks at recent stories from around the world’s polar regions. This week we look at the increase in Arctic heatwaves, the Antarctic sea ice which remains stable this year, a proposed road in Nunavut, and some icebergs spotted by Vendée Globe skippers.
The Polar Retrospective is a collaborative effort by the Polar Journal team. Each writer chooses a topic they found interesting and important in the past week. The intitials at the end of each section indicate the author. We hope you enjoy it.
Heatwaves in the Arctic Ocean: stronger, more frequent and with serious ecological consequences
A new study led by the Alfred Wegener Institute highlights the alarming intensification of marine heatwaves in the Arctic, driven by rising global temperatures and the rapid retreat of sea ice.
Using high-resolution climate models, the researchers found that marine heatwaves in the Arctic are expected to become significantly more intense throughout the 21st century, occurring abruptly and varying greatly in intensity from year to year.
The ecological consequences of these heatwaves are severe. Sudden and extreme temperature spikes place cold-adapted species under stress, pushing them to their physiological limits and making them more vulnerable to additional stressors, with all levels of the food web potentially affected simultaneously.
Moreover, increased ocean stratification and reduced mixing during heatwaves will limit nutrient availability, leading to reduced primary production and further cascading impacts on the entire food web—from plankton to marine mammals.
These changes could result in shifts in species composition, including a rise in heat-tolerant or invasive species, harmful algal blooms, and significant biodiversity loss.
The study underscores the urgent need for high-resolution models that integrate biological and physical processes to better understand and predict how Arctic ecosystems respond to intensifying ocean heatwaves. Such tools are vital for mitigating the effects of climate change on these fragile ecosystems. J.H.
Antarctic sea ice has a nice summer
The southern spring has been kind to Antarctic sea ice, after two particularly difficult years. According to data from the National Snow and Ice Data Center (NSIDC) published on the organization’s website this Tuesday, the sea ice extent at the end of December 2024 will be about the same as the average extent recorded between 1981 and 2010, i.e. 7.3 million km2. This contrasts with the averages recorded in 2023 and 2024, when the seasonal loss of sea ice was much greater.
Every summer, as temperatures rise, sea ice melts before refreezing as winter approaches. While this cycle is normal in the polar regions, it has become more pronounced under the influence of global warming, resulting in more ice melting during the boreal summer in the Arctic and the austral summer in the Antarctic.
But should we celebrate these results and think that Antarctic sea ice is doing better? Not really, according to the NSIDC. Satellite data showed significant summer melt between 2016 and 2023, leading scientists to believe that the trend would continue downwards. A favourable situation in recent months should therefore not contradict this concern, especially as Antarctic sea ice concentrations remain rather low over much of the pack.
As for the Arctic, the downward trend continues, with a sea ice extent of 11.42 million km2 in December. This is 1.42 million km2 less than the 1981-2010 average. M.B.
Link to NSIDC : https://nsidc.org/sea-ice-today/analyses/ringing-new-year-warm-arctic
New road to connect North West Passage to southern Canada
In the Canadian Arctic, roads are few and far between.
Most of the ones that do exist run across frozen water and are only open during the winter. At the moment, there is only one all-season link between the Canadian road network and its Arctic coast: The Inuvik–Tuktoyaktuk Highway in the Northwest Territories.
But now plans for another are underway. The Grays Bay Road and Port has been approved for an environmental review, Eye on the Arctic reports. If the review goes through, the road is expected to be complete by 2034.
The new gravel road will be 230-kilometre long, cost around one billion Canadian dollars, and is expected to lead to mining operations in the area. It will run through the western part of Nunavut before connecting to an ice road by the border to the Northwest Territories. So, while the road itself will be open all year, its connection south won’t be. O.E.
Icebergs on the Vendée Globe Route
“In the atmosphere, toward the southern horizon, stretched a dazzling white band. English whalers called it ‘ice-blink,'” described Pierre Aronnax, the fictional character from Jules Verne’s famous novel Twenty Thousand Leagues Under the Sea, as he journeyed toward Antarctica at latitudes now followed by the skippers of the Vendée Globe.
“Fiction aside, some competitors in this solo round-the-world sailing race encountered icebergs over a hundred meters high in early January, while their hulls are barely a few millimeters thick. “With a steel hull, it’s fine, but not with a carbon one,” remarked Éric Bellion, the first skipper to spot them. “It’s terrifying!”
Five other skippers shared their experiences, including young Violette Dorange. There was some admiration, but mostly fear of colliding with chunks of ice in the middle of the Pacific. New Zealander Conrad Colman commented, wide-eyed: “Oh my god! Icebergs!” Swiss sailor Oliver Heer spotted one as the sun dipped below the horizon: “The alarm on my radar did its job, but I’m pretty scared.” The race management team took action, tracking iceberg drifts and providing updates to the competitors. However, as race director Hubert Lemonnier explained, “Between analyzing satellite images and sending out the information, it takes 24 hours.”
A security perimeter around Antarctica had been established at the start of the race, evolving until the first boats passed, in the interest of fairness. Meanwhile, icebergs revealed their massive ridges of ice-landmarks once followed by early explorers to find Antarctica, back when it was still an empty space on the map. C.L.
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