Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


How Unknown Glaciers Contributed to Rising Sea Levels


Small glaciers, which are not registered in the inventories, contributed significantly to global rising sea levels in the 20th century. This is the result of a joint study by the University of Bremen and the University of Innsbruck. Ben Marzeion and David Parkes have now published the results of their research in the high-ranking specialist journal Nature.

The rising sea levels have several causes: thermal expansion of the water as it warms, melting glaciers and ice sheets, and finally the extraction of groundwater, which – after use in agriculture or industry – to a large extent also ends in the ocean.

© Ben Marzeion / Universität Bremen

The Taschachferner – a glacier in the Ötztal Alps in the Austrian province of Tyrol. This glacier has also shrunk considerably in recent years.

If the scientists add these different contributions together and compare them with the actual figures concerning rising sea levels, they will find that about five centimeters of the total rise since 1900 remain unexplained.

“We see that the sea has risen by 20 centimeters in the last century, but we can only explain 15 of them,” underlines Ben Marzeion, professor at the Institute of Geography at the University of Bremen.

Incomplete Inventories

“In the publication in the Nature journal, we now propose an explanation for this gap,” says Marzeion. “There is strong evidence that global glacier inventories are incomplete.” The Randolph Glacier Inventory provides data on almost all glaciers on Earth in computer-readable form and is an important basis for research.

However, it has been known for some time that it is very difficult to find and identify small glaciers in remote sensing data. Marzeion: “We could speak figuratively about the dark matter of glaciology.

There is strong statistical evidence that these glaciers exist, but we don’t know where they are,” David Parkes explains. “In addition, several glaciers disappeared during the 20th century. This means that they used to exist, but today they are rightly not present in the inventories.”

Explaining Gaps Completely

Parkes has now developed a statistical method to assess the past development of these unknown glaciers. The result is that they could fully explain the gap in the sea-level budget – the previously unexplained five-centimeter rise.

“This is surprising because these unknown glaciers are so small today that they will not contribute more than 0.2 to 0.3 centimeters to rising sea levels in the future,” he says.

They are therefore actually insignificant today compared to the known glaciers, which would cause an increase in sea levels of 40 to 50 centimeters in the event that they were to melt completely.

“The glaciers that are so tiny today that it is difficult to find them have been very important for the rising sea levels over the past 100 years, which, in turn, is why they are so tiny today,” says Professor Marzeion, summing up the research results that have now been published.


In 2015, Ben Marzeion took on a professorship for physical geography in the Faculty of Social Sciences at the University of Bremen, where his main area of interest is climate geography. His work focuses on the global modeling of the dynamics of mountain glaciers. The scientist is particularly concerned with the significance of glacier melting in relation to regional sea-level changes. In addition, he investigates the influence of glaciers on water availability, which can vary greatly from region to region, depending on the local climate and the needs of the local population.

David Parkes earned his doctorate through his participation in the climate geography working group in Innsbruck and Bremen, and is now employed at KU Leuven in Belgium. He is a mathematician and develops statistical methods that relate the complex spatial distribution of glaciers in mountain areas to the climatic conditions prevailing there. These methods make it possible to predict and reconstruct changes in glaciers for which very little information is available.

About Nature Journal:

Nature: a weekly journal of science is an English-language specialist journal with topics from various predominantly scientific disciplines. In 2014 Nature was the most cited interdisciplinary specialist journal worldwide. It is also one of the world’s most respected journals for natural sciences, alongside Science journal, which is published in the US.

Additional Information:

Digital Object Identifier DOI: 10.1038/s41586-018-0687-9

Wissenschaftliche Ansprechpartner:

Professor Ben Marzeion
Institute of Geography
Faculty of Social Sciences
University of Bremen
Tel.: +49 421 218-67170

David Parkes
Earth and Climate group
Earth and Life Institute
Université catholique de Louvain (Belgium)
Tel.: +44 75 97255728

Karla Götz | idw - Informationsdienst Wissenschaft
Further information:

Further reports about: GLACIERS Groundwater Small glaciers rising sea levels sea levels

More articles from Earth Sciences:

nachricht Live from the ocean research vessel Atlantis
13.12.2018 | National Science Foundation

nachricht NSF-supported scientists present new research results on Earth's critical zone
13.12.2018 | National Science Foundation

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Data use draining your battery? Tiny device to speed up memory while also saving power

The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.

Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...

Im Focus: An energy-efficient way to stay warm: Sew high-tech heating patches to your clothes

Personal patches could reduce energy waste in buildings, Rutgers-led study says

What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Latest News

Data use draining your battery? Tiny device to speed up memory while also saving power

14.12.2018 | Power and Electrical Engineering

Tangled magnetic fields power cosmic particle accelerators

14.12.2018 | Physics and Astronomy

In search of missing worlds, Hubble finds a fast evaporating exoplanet

14.12.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>