Map of larger glacial catchments in Iceland (light grey shading with white outline). Clicking on the map to enlarge it enables mouse over that allows identification of individual catchments.
The glaciers and ice caps of Iceland covered 11% of the land area of the country, up to about 2008. As of 2019[update] this was down to 10%. They have a considerable impact on its landscape and meteorology. Glaciers are also contributing to the Icelandic economy, with a tourist market that includes glacier trips on snowmobiles and glacier hiking tours. However, the recent loss of ice due to climate change is an increasing concern in Icelandic society.[1]
Glaciers can both grow in size and regress depending upon several factors of which climate and precipitation in the glaciers catchment are the most important. About 7,000 years ago, the Pleistocene ice from the last Ice Age over Iceland disappeared almost entirely, so the current glaciers in Iceland are not that old.[2]:377 In the case of Iceland as several large glaciers are over active volcanoes, geothermal melting can be a substantial component of the glacier ice mass balance.[3]:2 Accordingly Iceland's glacier area varies from year to year and some glaciers may grow while others regress. The tables below have to be interpreted considering such variations in time and do not include much other data that those who study glaciers would regard as important. Data that was gathered over many years in the 1890s, or even by the first complete aerial photographic survey between 1945 and 1946 is difficult to compare to the richer satellite studies and the on the ground measurements possible since the 1990's but such comparisons have been attempted.[3] Even so there are gaps in the data (see Table 2). Two different definitions of a glacier are usually used in current research and much Iceland work is closer to the definition:[3]:7
A perennial mass of ice, and possibly firn and snow, originating on the land surface by the recrystallization of snow or other forms of solid precipitation and showing evidence of past or present flow
An ice cap is a mass of glacial ice that covers less than 50,000km2 (19,000sqmi) of land area covering a highland area and they feed outlet glaciers.[4]:52 Many Icelandic ice caps and glaciers lie above volcanoes, such as Grímsvötn and Bárðarbunga, which lie under the largest ice cap, Vatnajökull. The caldera of Grímsvötn is about 100km2 (39sqmi) in area, and Bárðarbunga is about 60km2 (23sqmi) meaning a large amount of ice, given mean icecap thickness of about 200m (660ft) is at risk of geothermal melting.
When volcanic activity occurs under the glacier, the resulting meltwater can lead to a sudden glacial lake outburst flood, known in Icelandic as a jökulhlaup. However jökulhlaups are more commonly caused by accumulation of meltwater due to geothermal activity underneath the glacier. Jökulhlaups occasionally trigger volcanic eruptions through the sudden release of pressure. These eruptions occur towards the end of the Jökulhlaup.[5]:88
The glaciers are relevant enough in Icelandic geography that the four largest are represented blank in most of the maps of the administrative divisions of Iceland smaller than the regions.
Iceland is losing ice due to climate change. In 2008 its glaciers still covered 11% of the land area of the country, at about 11,100km2 (4,300sqmi) out of the total area of 103,125km2 (39,817sqmi).[2]:365,368As of 2019[update] this was down to 10%.[3]:2
Okjökull in Borgarfjörður, West Iceland, has lost its glacier title and is now simply known as Ok, losing the Icelandic word for glacier, jökull, as a suffix. In order to fit the criteria glaciers need to be thick enough to sink and move under their own weight, which any ice remaining of Okjökull can not do. Okjökull is the first Icelandic glacier to lose this title in an official manner,[6][7] but tens of smaller glaciers have disappeared up to 2019.[3]:27
These 13 largest glaciers had, at slightly different times around the year 2000, an aggregate area of 10,863km2 (4,194sqmi) (out of about 11,079km2 (4,278sqmi) for all glaciers of Iceland).[11] The total glacial area in 2019 was down to 10,400km2 (4,000sqmi), and had decreased by more than 2,200km2 (850sqmi) since the end of the 19th century.[3]:27
Glaciers
Glacier locations in Iceland as on this page
The list of glaciers below and their characteristics is incomplete. Many of the smaller glaciers that are presently only glacier remnants have not been added to the list. There are for example over 170 glaciers on the Tröllaskagi peninsula,[3]:3 northern Iceland and many have little significance or have regressed. Okjökull is mentioned in the table below although it is no longer recognised as a glacier as it has recent significance by its rate of disappearance of a large glacier due to climate change. In Iceland the recent maximum extent of glaciers occurred in a process from the onset of the Little Ice Age about 1450 CE and did not stop until about 1900 CE.[3]:1 Some outlet glaciers have shown marked surges over relatively short periods of time resulting in growth in glacial size.[3]:4 This has only changed the recent overall trend to smaller total area of glacial ice for a brief period in 1963–1964 from a surge in Brúarjökull.[3]:25 Other glaciers have been linked, for example in the 1980s Mýrdalsjökull and Eyjafjallajökull were one continuous ice cap.[12]
Iceland is an island country at the confluence of the North Atlantic and Arctic oceans, east of Greenland and immediately south of the Arctic Circle, atop the constructive boundary of the northern Mid-Atlantic Ridge. The island country is the world's 18th largest in area and one of the most sparsely populated. It is the westernmost European country when not including Greenland and has more land covered by glaciers than continental Europe. Its total size is 103,125 km2 (39,817 sq mi) and possesses an exclusive economic zone of 751,345 km2 (290,096 sq mi).
Vatnajökull is the largest and most voluminous ice cap in Iceland, and the second largest in area in Europe after the Severny Island ice cap of Novaya Zemlya. It is in the south-east of the island, covering approximately 10% of the country.
Langjökull is the second largest ice cap in Iceland, after Vatnajökull. It is situated in the west of the Icelandic interior or Highlands of Iceland and can be seen clearly from Haukadalur. It covers the higher parts of the Langjökull volcanic system.
Hofsjökull is the third largest ice cap in Iceland after Vatnajökull and Langjökull and covers the largest active central volcano in the country, which has the same name. It is situated in the west of the Highlands of Iceland and north of the mountain range Kerlingarfjöll, between the two largest glaciers of Iceland.
Mýrdalsjökull is an ice cap on the top of the Katla volcano in the south of Iceland. It is to the north of the town of Vík í Mýrdal and to the east of the smaller ice cap Eyjafjallajökull. Between these two glaciers is the Fimmvörðuháls pass.
Katla is an active volcano in southern Iceland. This volcano has been very active historically with at least twenty documented major eruptions since 2920 BC. In its recent history though, Katla has been less active as the last major eruption occurred in 1918. These eruptions have had a Volcanic Explosivity Index (VEI) of between 4 and 5 on a scale of 0 to 8. In comparison, the Eyjafjallajökull 2010 eruption had a VEI of 4. Larger VEI-5 eruptions are comparable to Mount St. Helens 1980 eruption. These eruptions have produced very large glacial outburst floods. Several smaller (minor) events measuring VEI-1 and below have occurred since.
Öræfajökull is an ice-covered volcano in south-east Iceland. The largest active volcano and the highest peak in Iceland at 2,110 metres (6,920 ft), it lies within the Vatnajökull National Park and is covered by part of the glacier.
Grímsvötn is an active volcano with a fissure system located in Vatnajökull National Park, Iceland. The volcano itself is completely subglacial and located under the northwestern side of the Vatnajökull ice cap. The subglacial caldera is at 64°25′N17°20′W, at an elevation of 1,725 m (5,659 ft). Beneath the caldera is the magma chamber of the Grímsvötn volcano.
A jökulhlaup is a type of glacial outburst flood. It is an Icelandic term that has been adopted in glaciological terminology in many languages. It originally referred to the well-known subglacial outburst floods from Vatnajökull, Iceland, which are triggered by geothermal heating and occasionally by a volcanic subglacial eruption, but it is now used to describe any large and abrupt release of water from a subglacial or proglacial lake/reservoir.
The geology of Iceland is unique and of particular interest to geologists. Iceland lies on the divergent boundary between the Eurasian plate and the North American plate. It also lies above a hotspot, the Iceland plume. The plume is believed to have caused the formation of Iceland itself, the island first appearing over the ocean surface about 16 to 18 million years ago. The result is an island characterized by repeated volcanism and geothermal phenomena such as geysers.
The subglacial Esjufjöll volcano is located in the south-east part of the Vatnajökull icecap. Esjufjöll is a strict nature reserve.
Torfajökull is a rhyolitic stratovolcano, with a large caldera capped by a glacier of the same name and associated with a complex of subglacial volcanoes. Torfajökull last erupted in 1477 and consists of the largest area of silicic extrusive rocks in Iceland. This is now known to be due to a VEI 5 eruption 55,000 years ago.
Tindfjallajökull is a glacier in the south of Iceland whose name is also given to the underlying stratovolcano. Tindfjöll is a ridge that extends to the south of the glacier and is an alternative name for the volcano. The name of the glacier in Icelandic means "Tindfjöll glacier".
Vatnajökull National Park is one of three national parks in Iceland. It encompasses all of Vatnajökull glacier and extensive surrounding areas. These include the national parks previously existing at Skaftafell in the southwest and Jökulsárgljúfur in the north.
Tungnafellsjökull is a icecap glacier upon a volcano of the same name in Iceland. The volcano is also known as Vonarskarð.
Thordarhyrna is one of seven subglacial volcanoes beneath the Vatnajokull glacier in Iceland. It is a paired active central volcano with Grímsvötn, and can be classified as part of the Grímsvötn-Laki volcanic system, with common fissure swarms to the south.
The Loki-Fögrufjöll is a subglacial volcano under the Vatnajökull glacier.
Gjálp is a hyaloclastite ridge (tindar) in Iceland under the Vatnajökull glacier shield. Its present form resulted from an eruption series in 1996 and it is probably part of the Grímsvötn volcanic system. However not all the scientists were of this opinion, as seismic studies are consistent with a 10 km (6.2 mi) lateral dike intrusion at about 5 km (3.1 mi) depth from Bárðarbunga being the trigger event. This does not exclude a shallower secondary intrusion from Grímsvötn being important in the subaerial eruption itself.
Ice cauldrons are ice formations within glaciers that cover some subglacial volcanoes. They can have circular to oblong forms. Their surface areas reach from some meters to up to 1 or more kilometers.
1 2 Cogley, J. G.; Hock, R.; Rasmussen, L. A.; Arendt, A. A.; Bauder, A.; Braithwaite, R. J.; Jansson, P.; Kaser, G.; Möller, M.; Nicholson, L.; Zemp, M. (2011). Glossary of Glacier Mass Balance and Related Terms. Paris: UNESCO-IHP, IHP-VII Technical Documents in Hydrology No. 86, IACS Contribution No. 2. pp.1–115. Retrieved 23 May 2024.:45
1 2 3 4 5 6 7 Baldursson, Snorri; Guðnason, Jónas; Hannesdóttir, Hrafnhildur; Þórðarson, Þorvaldur (2018). Nomination of Vatnajökull National Park dynamic nature of fire and ice for inclusion in the World Heritage List. Reykjavík: Vatnajökull National Park. ISBN978-9935-9343-3-8.
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