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What types of glaciers are there in Svalbard?

A quick glance at any glaciological textbook will present the reader with a mind-boggling array of different glacier types and classifications, but we can classify most of the glaciers in Svalbard into those that terminate on land, and those that terminate in the sea.

Glaciers that terminate in the sea tend to look more spectacular, as the lower friction associated with ice flowing into water generally means that ice will flow faster and crack, forming the extensive and beautiful crevasse fields that we see on glaciers such as Kronerbreen, and Tunabreen.

In contrast, land-based glaciers are likely to experience higher frictional forces at their bases and tend to flow much slower and show more uniform, less visually interesting (albeit easier to navigate!) surface features.

We can also classify according to something called thermal regime: the temperature of the ice. Glacier ice is denoted as being either ‘cold’ or ‘warm’. Setting aside the fact that all ice feels cold to the touch, warm ice is at the melting point (zero degrees Celsius) while cold ice is below the melting point.

This temperature classification may impact how fast glaciers flow or move, as glaciers with cold ice at their base will potentially ‘stick’ to that base and move slower, while glaciers with warm ice at their base will potentially slide and move faster. Many of the smaller glaciers in Svalbard are thought to be cold based.

However, ice also melts under pressure, so where thick glacier ice is present, cold ice at the base of a glacier can become warm glacier ice through the pressure exerted by hundreds of meters of ice. This then leads to a classification of some Svalbard glaciers being polythermal, where parts of the glacier are comprised of cold ice, and parts are comprised of warm ice.

The climate of Svalbard predisposes glaciers to be comprised of cold ice, but surface ice layers will warm in the summer months and potentially transition to warm ice. Finally, some glaciers are called ‘surge-type’ glaciers. These may terminate on land or in the sea and be comprised of warm ice, cold ice or be polythermal. Surge-type glaciers have periods of fast flow, meters or tens of meters per day, every few decades, although this period does vary.

Do glaciers in Svalbard differ from glaciers in other regions?

Glaciers in Svalbard have some characteristics that set them apart from glaciers in other regions. Firstly, Svalbard is one of a handful of locations where clusters of surge-type glaciers are found. The surge process is still poorly understood and there is no compelling explanation as to why surge-type glaciers are found in some regions and not others.

Second, as a center for Arctic glaciological research, the relatively small size of many Svalbard glaciers, as compared to somewhere like East Greenland for example, makes study easier, and since they are located in the middle of the world’s most rapidly warming region, they have attracted great scientific interest.

Glaciers are sensitive indicators of climate change, both through changes in snowfall, and temperature. Small glaciers generally respond far faster to environmental changes than large glaciers.

Finally, although not unique to Svalbard, the polythermal nature of many Svalbard glaciers adds great interest from a scientific perspective, especially as glaciers thin and pressure melting of ice tails off in some systems in response to that thinning, with resultant consequences for melt water production and glacier flow speeds.

How is the “health” of a glacier measured?

Glacier ice forms from snow that gets buried and compressed over many years. After the summer melt season, any snow that remains on the glacier is covered by fresh winter snowfall. This burial initiates a slow process where the snow is compressed and gradually transformed into dense glacier ice.

In Arctic glaciers, this process can take several decades, after which the newly formed glacier ice begins to move slowly down the valley, creating what we recognize as a glacier.

The impact of changes in snowfall on a glacier’s terminus (the front of the glacier) takes a long time to become visible. Snowfall in the glacier’s upper reaches (accumulation zone) takes years or even decades to influence the glacier’s terminus. During this time, other factors like temperature variations or glacier surging can cause the terminus to advance, retreat, or remain unchanged, making it difficult to assess the glacier’s overall health based on terminus position alone.

To truly know if our glacier is growing or shrinking, we need to calculate the mass balance.

Mass balance is the difference between the mass gained through snowfall and subsequent conversion to glacier ice, and the mass lost through melting and calving. Measuring this balance involves extensive fieldwork.

Globally, mass balance measurements are conducted on only a few glaciers, and in Svalbard, these are mostly on the west coast, which has a different climate from the east.

However, despite this relatively limited data, it is clear that Svalbard is warming rapidly, leading to widespread glacier shrinkage.

What is glacier shrinkage, and why is it particularly significant in Svalbard?

Globally, glaciers are not faring very well. Loss of land-based ice contributes to sea level rise, while the white and grey surfaces of snow and ice help reflect short wave radiation from the sun back into space, thereby helping to keep temperatures low; removal of that ‘whiteness’ inevitably means exposure of darker land and ocean surfaces and absorption of short-wave energy, with resultant warming.

This is especially an issue in the High Arctic, where sea ice acts like a giant white ‘umbrella’, helping to keep the region cool. Sea ice shrinkage is a major issue for Svalbard and the High Arctic, as not only does sea ice help regulate temperatures, but it is an important habitat for many marine species, including the iconic polar bear.

Snow and ice melt also provides an important water resource; globally approximately one fifth of the world’s population is directly or indirectly dependent on snow and ice melt for their water resources. When we factor in snow and ice melt irrigation of global ‘breadbaskets’, such as the Indo-Gangetic plain, from where global food and produce exports such as tea, rice and cotton originate, that one-fifth figure almost certainly represents a conservative estimate.

How quickly are Arctic glaciers shrinking?

The Arctic is currently warming faster than any other region and so inevitably, the glaciers of Svalbard are responding by exhibiting mass loss and shrinkage. Day to day weather can affect the mass or ‘health’ of glaciers. For example, rainfall will rapidly melt snow and ice, and we can see this with the significant increase in size of the river running through Longyearbyen, which is mainly fed by snow and ice melt from Longyearbreen.

Svalbard has also set several temperature records in recent years and these day-to-day weather extremes enhance melt. 21.7 degrees Celsius was recorded in Longyearbyen in 2022 and multiple incidences of temperatures in the high teens were measured in 2023.

Such weather events can be offset by healthy snowfall in the winter months and formation of new glacial ice, but the longer-term climate trends show the High Arctic becoming warmer and wetter and glaciers will respond to these longer term-trends, as they have done for millennia.

How does the future look like?

The outlook for Svalbard glaciers is not positive. Of course, larger systems will persist for many decades to come, but some smaller glaciers will doubtless be lost in coming years and all glaciers are suffering from a lack of snowfall accumulation, as spring melt comes earlier, freezing autumn temperatures arrive later, and the Arctic is becoming more prone to rainfall, which is very effective at melting snow and ice.

Record-breaking temperatures are adding to glacier shrinkage and with many smaller glaciers not reaping the benefits of temperature decline and cooling with altitude that larger systems flowing from higher elevations enjoy, they are particularly vulnerable.

So, it’s a triple whammy; reduced snowfall inputs, so less glacial ice being created, earlier arrival of spring melt in an increasingly wetter High Arctic and finally, rapidly increasing temperatures in the region.

Does their size matter?

The size of glaciers plays a crucial role in how quickly they respond to increasing temperatures and changes in snowfall. Smaller glaciers react more rapidly to environmental changes than larger ones. However, this doesn’t necessarily mean that shrinking glaciers will always produce more meltwater.

Initially, as glaciers begin to shrink, meltwater production often increases, creating what is known as the “meltwater discharge dividend.” This is currently being observed in regions like the Himalayas, where shrinking glaciers are temporarily releasing more water.

But as glaciers continue to shrink and reach a certain threshold, the trend can reverse. Even with rising temperatures and increased melt rates, meltwater production can decrease because the volume and surface area of ice have diminished so much that there is less snow and ice available to melt. This reduction in meltwater production from glaciers is now being seen in regions such as the Alps and the Andes.

What happens to an area after a glacier has melted away?

A completely melted glacier, will leave a characteristic landscape, like the mountainous regions of the UK and parts of mainland Norway. This results in a loss of reflectivity, and a change to sediment and nutrient delivery to down-valley and marine ecosystems, associated with changed meltwater inputs to these ecosystems.

How does glacier recession contribute to global sea-level rise?

Melt of land-based ice contributes to sea level rise, wherever it occurs, but unlike the Himalaya for example, many Svalbard glaciers reside at low altitudes, where temperatures are warmer and therefore they are particularly sensitive to any increase in air temperature.

Given that Svalbard ice represents approximately 6% of all global glacier ice, the impacts are 1.5-2.5 cm global sea level rise potential, if all glacial ice in the archipelago melts.

How certain are the estimates of ice loss for small and large glaciers?

Future estimates of ice loss in Svalbard depend on numerical modeling, but these predictions are uncertain because glaciers are complex and respond to many environmental factors, some of which are difficult to predict accurately.

There is also doubt over future emissions scenarios, which will impact both temperatures and precipitation levels and influence the extent of sea ice and ocean temperatures, both critical factors in shaping Arctic climate.

Have we already passed the point of no return?

There will be glaciers in Svalbard for many decades to come. However, we can expect to see accelerating rates of ice loss as the High Arctic both warms and becomes wetter.

Having worked in the Arctic since 1994, it has been obvious that ice loss has accelerated in the past decade and that trend will not be reversed in the foreseeable future.

Small glaciers will of course go first, and some have disappeared from the landscape already. Larger land based and marine-terminating glaciers will persist, but much reduced in size.

What are the implications for the local communities and the environment?

Snow and ice melt is used to supply drinking water in the settlements in Svalbard and so changing delivery of meltwaters associated with changing melt rates may pose water supply challenges in the future. With a warmer and wetter Arctic there is a greater chance of high river levels in glacier meltwater rivers, and this may pose a potential flood risk for areas such as Longyearbyen, while access to glaciers for science and tourism becomes more challenging if larger meltwater rivers need to be crossed.

Although not directly related to glacier shrinkage, warming accelerates melt of permafrost (permanently frozen ground) which, combined with a wetter Arctic, can result in a greater risk of landslides and other slope movements, with potential for impacts on local communities. Indeed, there are proposals to move the cemetery in Longyearbyen to reduce the potential for damage from landslides.

What is your message to people exploring Svalbard?

I would urge all visitors to consider how they travel to Svalbard; for example, although often not practical, where sea travel is possible, consider opting for this rather than flying.

Consider wants over needs when planning and when in Svalbard. Do we need to buy those cheap, imported plastic souvenirs? Do we have to buy the latest and greatest gear for the trip? Do we need to leave our waste in Svalbard before re-boarding our cruise ship?

We survived just fine in Svalbard in the early 1990s when the shop was tiny and only basic provisions could be purchased and when there was only one bar in Longyearbyen (the Huset). Minimize your consumption before and during your trip, minimize your environmental impact when in Svalbard and maximize your enjoyment of this wonderful environment!

Last update: 10. February 2025