Glaciers, or slow-moving ice rivers, have formed mountains and valleys throughout Earth’s history. They still flow and influence the terrain in numerous areas today. However, glaciers have far-reaching consequences beyond the landscape.
Lakes, rivers, and oceans receive nutrients from glacier melt. These nutrients can stimulate phytoplankton blooms, the foundation of aquatic and marine food systems. Meanwhile, progressive glacial melt maintains river ecosystems for plants and animals. Thus, glaciers frequently have an indirect effect on animals and fisheries.
Now, you might wonder how climate change affects Iceland’s glaciers. Well, let us discuss in detail.
Depending on their size and form, glaciers react differently to climate change, but most move their tip within a few years in reaction to a change in mass balance. The glacier will then retreat or advance for several years or decades before fully responding to a shift in climate. Short and steep valley glaciers change in a decade or two, whereas larger and less steep glaciers take much longer. The slope and structure of the underlying bed and the presence of glacial lakes that promote melting dictate how glaciers respond to a shift in mass balance.
The sensitivity of glaciers to climatic fluctuations is defined as the change in mass balance or volume in response to a specific climate change (temperature and precipitation). According to recent modeling studies examining their susceptibility to temperature and precipitation fluctuations, a simple 1°C of warming would result in a 25-35% loss of volume for the outlet glaciers of Skálafellsjökull, Heinabergsjökull, and Fláajökull. A 2°C warming would result in around 60% of the original ice volume being lost after running the model for about 100 years. We can presume that one degree Celsius of warming is negligible but substantially influences glaciers.
Greenland and Antarctica are changing dramatically and at a faster rate than anticipated. As meltwater pools in several surface ponds drain abruptly and travel down moulins to the glacier bed, the ablation zones have increased and reached higher elevations. As a result of this development, the rate at which outlet glaciers calve and enter the ocean rises along with the velocity of the ice flow.
Increased Volcanic Activity
The decrease of surface ice load as glaciers recede has the potential to increase magma formation and volcanic activity. It may already be occurring in Vatnajökull’s subglacial volcanic systems. Model estimates replicating the influence of glacier changes between 1890 and 2010 show that magma generation has increased by 100-135%, equivalent to an additional 0.2 km3/year of magma beneath Iceland. If 25% of this magma reaches the surface, it will be comparable to the 2010 Eyjafjallajökull summit eruption every seventh year.
Sea-level Rise
If the 3500 km3 of ice found in Icelandic glaciers melt, the global sea level would rise by 1 centimeter. In context, the Greenland Ice Sheet has lost twice as much ice per year as the SE outflow glaciers of Vatnajökull have since approximately 1890. The melting water from glaciers in Antarctica and Greenland is the principal source of global sea-level rise, which averages 3-4 millimeters annually. Thermal expansion due to ocean warming also increases sea-level surges, accounting for almost half of the increase over the last century.
Tourism
As the outlet glaciers melt, access to guided glacier excursions gets increasingly difficult in some areas, including day tours from Reykjavik. It applies to volunteers of the Iceland Glaciological Society who monitor the retreat! On the other hand, more options for boat cruises on glacier lakes may emerge. Ice caves are becoming increasingly popular as a winter tourist destination. Meltwater runs beneath the glacier, carving tunnels into the ice. The increased air temperature in the spring weakens the ice caves’ walls and ceilings, which may collapse. Flash floods near the caves throughout the summer can also be hazardous. With increasing glacial excursions around Vatnajökull, there are more possibilities to teach and communicate about climate change and receding glaciers.
Rock Avalanches
Many glaciers in southeast Iceland, including Morsárjökull and Svínafellsjökull, have sustained damage from landslides and rock avalanches within the previous ten years. Rock avalanches’ leading causes include melting glaciers, weakening mountain slopes and glacier retreat, melting permafrost, and bedrock instability.
Crustal Uplift
As the Vatnajökull ice cap thins and retreats, the underlying crust rebounds at an increasing rate. The largest uplift rate occurs closest to the glacier margin when the greatest mass loss occurs. Jökulheimar at the ice cap’s western margin has 40 mm of annual uplift, while Höfn in Hornafjörður, southeast of the glacier, experiences only 12 mm. The future of shipping through the inlet of Hornafjörður Bay is uncertain due to the area’s uplift.
Conclusion
Iceland’s glaciers contribute significantly to the country’s geography, culture, and economy. They contain irreplaceable environmental data about previous climatic conditions, weather, and earthquake events. This information is disappearing at an alarming rate. Glaciers have lost an incredible four billion tons of ice over the last 130 years, making them the fastest-shrinking glaciers outside the polar ice caps. The majority of this loss—16 percent of their overall volume—has occurred during the previous 25 years.
Given that glaciers cover 11% of Iceland, this rate of decline poses major concerns to livelihoods and the economy. Land ownership, use, conservation, and resource governance must all be reviewed as the country gains land owing to melting glaciers. Icelandic policymakers, scientists, and those whose livelihoods are at risk (such as those in the tourism industry) are beginning to consider adaptation strategies.