Mass balance for glaciers in Svalbard

The front of a glacier in Kongsfjorden, Svalbard, seen from the ocean.
Photo: Stein Ø. Nilsen / Norwegian Polar Institute

Melting glaciers are in focus due to climate change and rising temperatures. In Svalbard, several glaciers are monitored to detect the potential loss of mass. Mass balance is the difference between glacier growth in winter due to precipitation and glacier reduction in summer due to melting. All glaciers presented here have had a reduction in mass through the monitoring period.

What is being monitored?

Mass balance for glaciers in Svalbard

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The figure shows the cumulative net balance throughout the monitoring periods for the five glaciers, Austre Brøggerbreen, Midtre Lovénbreen, Kongsvegen, Kronebreen/Holtedahlfonna and Etonbreen (Austfonna). Cumulative net balance is roughly equivalent to the volume change; there is a strong negative trend for Austre Brøggerbreen and Midtre Lovénbreen, in accordance with the observed retreat of these glaciers. There was a relatively long period of increased loss from 2000 to 2005, longer than any other periods in the time series. Kongsvegen increased in volume until 2002, but since then the mass balance has also been increasingly negative.

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The figure shows the winter, summer and net balance for Austre Brøggerbreen measured in metres water equivalents. The mass balance has been almost exclusively negative throughout the measurement period.

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The figure shows the winter, summer and net balance for Midtre Lovénbreen measured in metres water equivalents. The mass balance has been almost exclusively negative throughout the measurement period.

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The winter, summer and net balance for Kongsvegen. The mass balance has been positive for Kongsvegen in most years throughout the measurement period. This difference is because Kongsvegen is located higher than the other glaciers and has a larger accumulation area. However, the net balance on Kongsvegen has gradually shifted from positive to negative and the glacier now seems to be in a long-term decline.

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The figure shows the winter, summer and net balance with and witout calving for Kronebreen and Holtedahlfonna, measured as metre water equivalents. The mass balance has beenvarying around zero during the measurement period, but would be almost exclusively negative if calving and marine melting at the terminus were accounted for.

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The figure shows the winter, summer and net balance with and without calving, for Etonbreen on Austfonna ice cap, measured as metre water equivalents. The net mass balance has typically been close to zero, except for an exceptionally positive year in 2008 and two very negative years in 2004 and 2013. Calving and marine melting at the terminus cause a small additional mass loss. 

Status and trend

All 5 glaciers lost mass during their respective monitoring periods.

In the period 1986–2002 Kongsvegen had a positive trend, due mainly to the fact that Kongsvegen lies at higher altitudes than the small glaciers Austre Brøggerbreen and Midtre Lovénbreen, and therefore has a significantly larger accumulation area. After 2002, Kongsvegen also shows a declining trend after several years with unusually negative mass balances.

The accumulation area of Kronebreen/Holtedahlfonna lies even higher than at Kongsvegen, but since there is less winter precipitation on Holtedahlfonna compared to Kongsvegen, the overall mass balance is about the same as Kongsvegen. Etonbreen on Austfonna has not changed much during the measurement period except from a few summers with exceptionally high or low ablation. 

Causal factors

Mass balance is controlled by the amount of precipitation on the glacier in winter and the amount of melting in summer. Climate change is thus the main reason for a negative mass balance for glaciers.

Consequences

An important reason for monitoring mass balance is to quantify how much the melting glaciers of Svalbard contribute to rising sea level.

About a third of the global sea-level rise is due to melting of "small" glaciers, meaning all glaciers except Greenland and Antarctica, noting quite large error margins for the estimates. Hence, it is important to quantify the sea level contributions from the different ice-covered areas.

Svalbard plays a substantial role in this as it has about 10% of the total ice-covered area in the Arctic (except Greenland). In addition the melting rates in Svalbard are relatively high due to Svalbard's location in a relatively warm part of the Arctic.

About the monitoring

The mass balance of a glacier is the difference between accumulation in winter and ablation in summer, and is thus a measure of whether the glacier as a whole is increasing or shrinking. The mass balance is primarily dependent upon the precipitation in winter and the temperature in summer, but calving and marine melting are also important for some glaciers that terminate in the ocean.

It is interesting to monitor mass balance because melting of glaciers can contribute to sea-level rise. Glaciers also influence the local climate and the conditions for fauna and flora in Svalbard.

Places and areas

Relations to other monitoring

Monitoring programme
International environmental agreements
Voluntary international cooperation
Related monitoring