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Climate change in Svalbard’s fjords and the Arctic Ocean

Posted on 18. December 2024 by Rolf Stange

A few weeks ago, I wrote about Record melting of Svalbard’s glaciers in 2024, on this site, focussing on consequences of climate change on land.

But of course the changes are not limited to the land; the sea is also affected. Or, perhaps more accurately, it plays a major, driving role.

The Gulf Stream

In the North Atlantic, much is known to depend on the Gulf Stream. With its comparatively warm water masses, it brings enormous amounts of heat from the south and thus ensures the relatively mild climate in the highest latitudes such as 78 degrees north, where the Isfjord today remains largely ice-free all year round, while some fjords in northernmost Greenland or Canada (Ellesmere Island) only become ice-free briefly in summer or not at all.

Even small changes in the Gulf Stream have a massive impact on the regional climate in the north-east Atlantic. If the Gulf Stream brings a little more warm water or if the water is a little warmer, the North Atlantic will become considerably warmer. If the supply of warm water decreases or no longer reaches as far north, a regional cooling could also occur that could affect the whole of north-west Europe. In the long term, this scenario cannot be ruled out as part of climate change, but the opposite is currently the case.

Kongsfjord

Jørgen Berge from the University of Tromsø has been keeping a close eye on Kongsfjord for more than 20 years. As the research settlement of Ny-Ålesund is located in Kongsfjord, this fjord has been studied closely for a long time, with decades of data available on all kinds of details. In addition, the fjord is located on the part of the west coast that is most strongly influenced by the Gulf Stream, so it can serve as an early warning system for changes in these currents and their local effects.

Kongsfjord near Ny-Ålesund: an oceanographic and marine biology research laboratory.

Berge told Barentsobserver about his work and observations. The result anticipated: a ‘radical change in the marine ecosystem.’

According to Berge, the water masses in the Kongsfjord are warming by 0.1 degrees per year across the entire water column, i.e. by no less than 2 degrees in just 20 years. Two degrees is quite enough to drastically change the oceanographic-ecological character of a sea area – and the warming does not stop. The character of the Kongsfjord has changed from ‘arctic’ to ‘Atlantic’ during this time. In oceanographic terms, this initially means that the water is warmer and saltier.

The ecosystem: plankton and seabirds

Of course, this is not without consequences for the ecosystem. High-arctic, fat-rich plankton such as the copepod Calanus glacialis is increasingly being displaced by its subarctic and less fat-rich relatives Calanus finnmarchicus and Calanus hyperboreus, which has consequences for seabirds that feed on plankton. The high Arctic Little auks in particular, which used to be – and still are, as of now – very numerous, prefer to feed on the energy-rich Calanus glacialis. If they have to rely more and more on their less energy-rich relatives, their diet will become increasingly problematic.

Little auks on the west coast of Spitsbergen.

Recent history shows that the breeding populations of seabirds are shrinking almost everywhere in the North Atlantic. The little auks still seem to be doing quite well, but it is very difficult to count these very small birds that breed invisibly under rocks. The case is clear for guillemots, puffins and gulls, where some colonies in northern Norway have practically collapsed since the 1980s. Disappeared.

Fjord ice: ringed seals and harbour seals

Another aspect is that the Kongsfjord has hardly frozen over for around 15 years. Ringed seals, once the most numerous seals in the fjords of Spitsbergen, need the fjord ice in spring to give birth to their young and to rest. The harbour seal, which is also known from the southern North Sea, is now much more common on the west coast of Svalbard than the ringed seal, which is very similar in appearance. Seals have been naturally occurring in Svalbard for thousands of years and this observation may be coincidental, but it fits in with the scientifically confirmed development of the fjords from a highly arctic ecosystem to an Atlantic one.

High Arctic ringed seal (left), subarctic harbour seal.
Both live on the west coast of Spitsbergen.

Fish, mussels and temperature records

Berge also speaks of a change in the species composition of fish and mussels. Species such as herring and capelin, which one would not expect to find in high Arctic fjords, are spreading, as are mussels.

More and more common in Svalbard: blue mussels.

Global warming is more noticeable at the poles than at lower latitudes; it is estimated that the Arctic is warming by a factor of three to four more than other regions. If one hopes that climate change can somehow still be limited to a warming of 1.5-2 degrees, then this figure is the global average. For the Arctic, you can multiply that by three or four.

In recent years, record temperatures have been regularly measured in Svalbard, most recently on 11 August at 20.3 degrees, the highest value ever measured on an August day near Longyearbyen.

Even the previously high Arctic fjords in the north-east of Svalbard will not remain unaffected by this development. This is confirmed both by a regular look at the ice map and by personal experience in the fjords of Nordaustland and in Hinlopen Strait, where the previously widespread water temperatures of around 0 degrees are now rather rare and small-scale, especially in the southern Hinlopen Strait and on the southern side of Nordaustland, where the cold East Spitsbergen Current from the Arctic Basin is still exerting its influence. In the northern Hinlopen Strait and in the fjords in the west and north of Nordaustland and up to Sjuøyane, water temperatures of 6-8 degrees are increasingly common, indicating the increasing influence of mild Atlantic water (Gulf Stream).

Rarely ice-free in the past, now regularly in summer:
Fjords on the north coast of Nordaustland.

The Arctic Ocean: from white to blue

The sea ice of the Arctic Ocean is both a victim and a driver of this development. This is one of those feedback effects in the global climate system where the effect reinforces the cause. In this case, an area of water that has become ice-free due to warming no longer reflects the sun’s rays, but absorbs them and converts them into heat, which in turn melts even more ice and even larger areas of water absorb the sun’s rays … and so it goes on.

According to a study recently published in Nature Communications, the Arctic Ocean could become ice-free on a daily basis by around 2030. This study is the first to look at the development on a daily rather than a monthly basis. The Arctic Ocean could therefore be ice-free on a daily basis in a few years’ time if warm winters with little ice formation are followed by warm early summers with high ice loss.

The Arctic Ocean of the future: increasingly blue instead of white.

On the other hand, the study also describes scenarios according to which an ice-free Arctic Ocean will not be observed by the year 2100. Both possibilities are rather extreme scenarios; the real development may lie somewhere in between. Or not, the extreme scenarios are also possible according to the scientific models.

As Jørgen Berge told Barentsobserver: ‘It is likely that the central Arctic Ocean will evolve from a white (ice-covered) ocean to a blue (open water) ocean. What that means, we don’t know.’

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