From The University of Copenhagen [Københavns Universitet](DK) and The Niels Bohr Institute [Niels Bohr Institutet] (DK): “Ancient ice reveals scores of gigantic volcanic eruptions”

From The University of Copenhagen [Københavns Universitet](DK)


Niels Bohr Institute bloc

The Niels Bohr Institute [Niels Bohr Institutet] (DK)

16 March 2022

Anders Svensson
Associate Professor
Niels Bohr Institute
University of Copenhagen
+45 35 32 06 16

Maria Hornbek
Faculty of Science
University of Copenhagen
+45 22 95 42 83

16 March 2022


Ice cores drilled in Antarctica and Greenland have revealed gigantic volcanic eruptions during the last ice age. Sixty-nine of these were larger than any eruption in modern history. According to the University of Copenhagen physicists behind the research, these eruptions can teach us about our planet’s sensitivity to climate change.

For many people, the mention of a volcanic eruption conjures up doomsday scenarios that include deafening explosions, dark ash billowing into the stratosphere and gloopy lava burying everything in its path as panicked humans run for their lives. While such an eruption could theoretically happen tomorrow, we have had to make do with disaster films and books when it comes to truly massive volcanic eruptions in the modern era.

“We haven’t experienced any of history’s largest volcanic eruptions. We can see that now. Eyjafjellajökull, which paralysed European air traffic in 2010, pales in comparison to the eruptions we identified further back in time.

Eruption at Fimmvörðuháls at dusk.
27 March 2010. Credit: Boaworm

Many of these were larger than any eruption over the last 2,500 years,” says Associate Professor Anders Svensson of the University of Copenhagen’s Niels Bohr Institute.

By comparing ice cores drilled in Antarctica and Greenland, he and his fellow researchers managed to estimate the quantity and intensity of volcanic eruptions over the last 60,000 years. Estimates of volcanic eruptions more than 2,500 years ago have been associated with great uncertainty and a lack of precision, until now.


Volcanic eruptions are classified by their size on the so-called Volcanic Explosivity Index (VEI), which ranges from 1-8.

Etna, Italy (1669): 3 on the VEI scale
Eyjafjellajökul, Iceland (2010): 4 on the VEI scale
Vesuvius, Italy (year 79): 5 on the VEI scale
Laki, Iceland (1783): 6 on the VEI scale
Krakatau, Indonesia (1883): 6 on the VEI scale
Tambora, Indonesia (1815): 7 on the VEI scale
Lake Taupo, New Zealand (26,500 years ago): 8 on the VEI scale
Toba, Indonesia (74,000 years ago): 8 on the VEI scale

Sixty-nine eruptions larger than Mount Tambora

Eighty-five of the volcanic eruptions identified by the researchers were large global eruptions. Sixty-nine of these are estimated to be larger than the 1815 eruption of Mount Tambora in Indonesia – the largest volcanic eruption in recorded human history. So much sulfuric acid was ejected into the stratosphere by the Tambora eruption that it blocked sunlight and caused global cooling in the years that followed. The eruption also caused tsunamis, drought, famine and at least 80,000 deaths.

“To reconstruct ancient volcanic eruptions, ice cores offer a few advantages over other methods. Whenever a really large eruption occurs, sulfuric acid is ejected into the upper atmosphere, which is then distributed globally – including onto Greenland and Antarctica. We can estimate the size of an eruption by looking at the amount of sulfuric acid that has fallen,” explains Anders Svensson.

In a previous study, the researchers managed to synchronize ice cores from Antarctica and Greenland – i.e., to date the respective core layers on the same time scale. By doing so, they were able to compare sulphur residues in ice and deduce when sulfuric acid spread to both poles after globally significant eruptions.

Anders Svensson inspecting an icecore in Greenland (credit: NEEM [North Greenland Eemian Ice Drilling])

When will it happen again?

“The new 60,000-year timeline of volcanic eruptions supplies us with better statistics than ever before. Now we can see that many more of these great eruptions occurred during the prehistoric Ice Age than in modern times. Because large eruptions are relatively rare, a long timeline is needed to know when they occur. That is what we now have,” says Anders Svensson.

One may be left wondering when the next of these massive eruptions will occur. But Svensson isn’t ready to make any concrete predictions:

“Three eruptions of the largest known category occurred during the entire period we studied, so-called VEI-8 eruptions (see fact box). So, we can expect more at some point, but we just don’t know if that will be in a hundred or a few thousand years. Tambora sized eruptions appears to erupt once or twice every thousand years, so the wait for that may be shorter.”

How was climate affected?

When powerful enough, volcanic eruptions can affect global climate, where there is typically a 5-10- year period of cooling. As such, there is great interest in mapping the major eruptions of the past – as they can help us look into the future.

“Ice cores contain information about temperatures before and after the eruptions, which allows us to calculate the effect on climate. As large eruptions tell us a lot about how sensitive our planet is to changes in the climate system, they can be useful for climate predictions,” explains Anders Svensson.

Determining Earth’s climate sensitivity is an Achilles heel of current climate models. Svensson concludes:

“The current IPCC models do not have a firm grasp of climate sensitivity – i.e., what the effect of a doubling of CO2 in the atmosphere will be. Vulcanism can supply us with answers as to how much temperature changes when Earths atmospheric radiation budget changes, whether due to CO2 or a blanket of sulphur particles. So, when we have estimated the effects of large volcanic eruptions on climate, we will be able to use the result to improve climate models.”

The recent study is published in the journal, Climate of the Past.

The researchers who contributed to the study are: Jiamei Lin, Anders Svensson, Christine S. Hvidberg, Johannes Lohmann, Steffen Kristiansen, Dorthe Dahl-Jensen, Jørgen P. Steffensen, Sune O. Rasmussen, Eliza Cook, Helle Astrid Kjær and Bo M. Vinther from the Niels Bohr Institute at the University of Copenhagen; Hubertus Fischer, Thomas Stocker, Michael Sigl and Matthias Bigler of The University of Bern [Universität Bern](CH); Mirko Severi and Rita Traversi of the The University of Florence [Università degli Studi di Firenze](IT) and Robert Mulvaney of the British Antarctic Survey in the UK.

See the full article here .


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Niels Bohr Institute Campus

The Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

During the 1920s, and 1930s, the Institute was the centre of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK).

Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University , The Australian National University (AU), and University of California-Berkeley , amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

U Copenhagen campus

The University of Copenhagen [Københavns Universitet] (DK)] is a public research university in Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia, and ranks as one of the top universities in the Nordic countries and Europe.

Its establishment sanctioned by Pope Sixtus IV, the University of Copenhagen was founded by Christian I of Denmark as a Catholic teaching institution with a predominantly theological focus. After 1537, it became a Lutheran seminary under King Christian III. Up until the 18th century, the university was primarily concerned with educating clergymen. Through various reforms in the 18th and 19th century, the University of Copenhagen was transformed into a modern, secular university, with science and the humanities replacing theology as the main subjects studied and taught.

The University of Copenhagen consists of six different faculties, with teaching taking place in its four distinct campuses, all situated in Copenhagen. The university operates 36 different departments and 122 separate research centres in Copenhagen, as well as a number of museums and botanical gardens in and outside the Danish capital. The University of Copenhagen also owns and operates multiple research stations around Denmark, with two additional ones located in Greenland. Additionally, The Faculty of Health and Medical Sciences and the public hospitals of the Capital and Zealand Region of Denmark constitute the conglomerate Copenhagen University Hospital.

A number of prominent scientific theories and schools of thought are namesakes of the University of Copenhagen. The famous Copenhagen Interpretation of quantum mechanics was conceived at the Niels Bohr Institute [Niels Bohr Institutet](DK), which is part of the university. The Department of Political Science birthed the Copenhagen School of Security Studies which is also named after the university. Others include the Copenhagen School of Theology and the Copenhagen School of Linguistics.

As of October 2020, 39 Nobel laureates and 1 Turing Award laureate have been affiliated with the University of Copenhagen as students, alumni or faculty. Alumni include one president of the United Nations General Assembly and at least 24 prime ministers of Denmark. The University of Copenhagen fosters entrepreneurship, and between 5 and 6 start-ups are founded by students, alumni or faculty members each week.


The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University (US), The Australian National University (AU), and University of California, Berkeley(US), amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

The University of Copenhagen was founded in 1479 and is the oldest university in Denmark. In 1474, Christian I of Denmark journeyed to Rome to visit Pope Sixtus IV, whom Christian I hoped to persuade into issuing a papal bull permitting the establishment of university in Denmark. Christian I failed to persuade the pope to issue the bull however and the king returned to Denmark the same year empty-handed. In 1475 Christian I’s wife Dorothea of Brandenburg Queen of Denmark made the same journey to Rome as her husband did a year before. Unlike Christian I Dorothea managed to persuade Pope Sixtus IV into issuing the papal bull. On the 19th of June, 1475 Pope Sixtus IV issued an official papal bull permitting the establishment of what was to become the University of Copenhagen.

On the 4th of October, 1478 Christian I of Denmark issued a royal decree by which he officially established the University of Copenhagen. In this decree Christian I set down the rules and laws governing the university. The royal decree elected magistar Peder Albertsen as vice chancellor of the university and the task was his to employ various learned scholars at the new university and thereby establish its first four faculties: theology; law; medicine; and philosophy. The royal decree made the University of Copenhagen enjoy royal patronage from its very beginning. Furthermore, the university was explicitly established as an autonomous institution giving it a great degree of juridical freedom. As such the University of Copenhagen was to be administered without royal interference and it was not subject to the usual laws governing the Danish people.

The University of Copenhagen was closed by the Church in 1531 to stop the spread of Protestantism and re-established in 1537 by King Christian III after the Lutheran Reformation and transformed into an evangelical-Lutheran seminary. Between 1675 and 1788 the university introduced the concept of degree examinations. An examination for theology was added in 1675 followed by law in 1736. By 1788 all faculties required an examination before they would issue a degree.

In 1807 the British Bombardment of Copenhagen destroyed most of the university’s buildings. By 1836 however the new main building of the university was inaugurated amid extensive building that continued until the end of the century. The University Library (now a part of the Royal Library); the Zoological Museum; the Geological Museum; the Botanic Garden with greenhouses; and the Technical College were also established during this period.

Between 1842 and 1850 the faculties at the university were restructured. Starting in 1842 the University Faculty of Medicine and the Academy of Surgeons merged to form the Faculty of Medical Science while in 1848 the Faculty of Law was reorganised and became the Faculty of Jurisprudence and Political Science. In 1850 the Faculty of Mathematics and Science was separated from the Faculty of Philosophy. In 1845 and 1862 Copenhagen co-hosted nordic student meetings with Lund University [Lunds universitet] (SE).

The first female student was enrolled at the university in 1877. The university underwent explosive growth between 1960 and 1980. The number of students rose from around 6,000 in 1960 to about 26,000 in 1980 with a correspondingly large growth in the number of employees. Buildings built during this time period include the new Zoological Museum; the Hans Christian Ørsted and August Krogh Institutes; the campus centre on Amager Island; and the Panum Institute.

The new university statute instituted in 1970 involved democratisation of the management of the university. It was modified in 1973 and subsequently applied to all higher education institutions in Denmark. The democratisation was later reversed with the 2003 university reforms. Further change in the structure of the university from 1990 to 1993 made a Bachelor’s degree programme mandatory in virtually all subjects.

Also in 1993 the law departments broke off from the Faculty of Social Sciences to form a separate Faculty of Law. In 1994 the University of Copenhagen designated environmental studies; north–south relations; and biotechnology as areas of special priority according to its new long-term plan. Starting in 1996 and continuing to the present the university planned new buildings including for the University of Copenhagen Faculty of Humanities at Amager (Ørestaden) along with a Biotechnology Centre. By 1999 the student population had grown to exceed 35,000 resulting in the university appointing additional professors and other personnel.

In 2003 the revised Danish university law removed faculty staff and students from the university decision process creating a top-down control structure that has been described as absolute monarchy since leaders are granted extensive powers while being appointed exclusively by higher levels in the organization.

In 2005 the Center for Health and Society (Center for Sundhed og Samfund – CSS) opened in central Copenhagen housing the Faculty of Social Sciences and Institute of Public Health which until then had been located in various places throughout the city. In May 2006 the university announced further plans to leave many of its old buildings in the inner city of Copenhagen- an area that has been home to the university for more than 500 years. The purpose of this has been to gather the university’s many departments and faculties on three larger campuses in order to create a bigger more concentrated and modern student environment with better teaching facilities as well as to save money on rent and maintenance of the old buildings. The concentration of facilities on larger campuses also allows for more inter-disciplinary cooperation. For example the Departments of Political Science and Sociology are now located in the same facilities at CSS and can pool resources more easily.

In January 2007 the University of Copenhagen merged with the Royal Veterinary and Agricultural University and the Danish University of Pharmaceutical Science. The two universities were converted into faculties under the University of Copenhagen and were renamed as the Faculty of Life Sciences and the Faculty of Pharmaceutical Sciences. In January 2012 the Faculty of Pharmaceutical Sciences and the veterinary third of the Faculty of Life Sciences merged with the Faculty of Health Sciences forming the Faculty of Health and Medical Sciences and the other two thirds of the Faculty of Life Sciences were merged into the Faculty of Science.

Cooperative agreements with other universities

The university cooperates with universities around the world. In January 2006, the University of Copenhagen entered into a partnership of ten top universities, along with the Australian National University (AU), Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich](CH), The National University of Singapore [Universiti Nasional Singapura] (SG), Peking University [北京大学](CN), University of California Berkeley (US), University of Cambridge (UK), University of Oxford (UK), University of Tokyo {東京大学](JP) and Yale University (US). The partnership is referred to as the International Alliance of Research Universities (IARU).

The Department of Scandinavian Studies and Linguistics at University of Copenhagen signed a cooperation agreement with the Danish Royal School of Library and Information Science in 2009.