The Earth’s crust under Iceland is rebounding as global warming melts the island’s great ice caps, according to a new study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.
The paper is the first to show the current fast uplift of the Icelandic crust is a result of accelerated melting of the island’s glaciers and coincides with the onset of warming that began about 30 years ago, according the study’s authors.
This global positioning satellite receiver is part of Iceland’s network of 62 such receivers that geoscientists are using to detect movements of the Icelandic crust that are as small as one millimeter per year. Langjökull glacier is in the background.
Credit: Richard A. Bennett/ University of Arizona Department of Geosciences.
Usage restrictions: This photo of a GPS receiver in Iceland by Richard A. Bennett may only be used to illustrate a story about the research described in the accompanying news release, “Iceland rises as its glaciers melt from climate change.” Please make sure to credit the photo as requested. Do not post this image independent of the story.
Some sites in south-central Iceland are moving upward as much as 35 millimeters (1.4 inches) per year – a speed that surprised the researchers.
“Our research makes the connection between recent accelerated uplift and the accelerated melting of the Icelandic ice caps,” said Kathleen Compton, a geosciences doctoral candidate at the University of Arizona in Tucson, and lead author of the new paper.
This global positioning satellite receiver is part of Iceland’s network of 62 such receivers that geoscientists are using to detect movements of the Icelandic crust that are as small as one millimeter per year. Langjökull glacier is in the background. Credit: Richard A. Bennett/ University of Arizona Department of Geosciences.
Geologists have long known that as glaciers melt and become lighter, the Earth rebounds as the weight of the ice decreases.
Whether the current rebound geologists detect is related to past deglaciation or modern ice loss has been an open question until now, said co-author Richard Bennett, a University of Arizona associate professor of geosciences.
“Iceland is the first place we can say accelerated uplift means accelerated ice mass loss,” Bennett said.
To figure out how fast the crust was moving upward, the team used a network of 62 global positioning satellite receivers fastened to rocks throughout Iceland. By tracking the position of the GPS receivers year after year, the scientists “watch” the rocks move and can calculate how far they have traveled – a technique called geodesy.
The new work shows that, at least for Iceland, the land’s current accelerating uplift is directly related to the thinning of glaciers and to global warming.
“What we’re observing is a climatically induced change in the Earth’s surface,” Bennett said.
He added there is geological evidence that during the past deglaciation roughly 12,000 years ago, volcanic activity in some regions of Iceland increased thirtyfold.
Others have estimated the Icelandic crust’s rebound from warming-induced ice loss could increase the frequency of volcanic eruptions such as the 2010 eruption of Eyjafjallajökull, which had negative economic consequences worldwide.
Some of Iceland’s GPS receivers have been in place since 1995. Bennett, Sigrun Hreinsdóttir of GNS Science in Avalon, New Zealand, and colleagues had installed 20 GPS receivers in Iceland in 2006 and 2009, thus boosting the coverage of the nation’s geodesy network. In central and southern Iceland, where five of the largest ice caps are located, the receivers are 30 kilometers (18 miles) or less apart on average.
The team primarily used the geodesy network to track geological activity such as earthquakes and volcanic eruptions.
In 2013, Bennett noticed one of the long-running stations in the center of the country was showing that site was rebounding at an accelerated rate. He wondered about it, so he and his colleagues checked the nearby stations to see if they had recorded the same changes.
“The striking answer was, yes, they all do,” he said. “We wondered what in the world could be causing this?”
The team began systematically analyzing years of signals from the entire network and found the fastest uplift was the region between several large ice caps. The rate of uplift slowed the farther the receiver was from the ice cap region.
Other researchers had been measuring ice loss and observed a notable uptick in the rate of melting since 1995. Temperature records for Iceland, some of which go back to the 1800s, show temperatures increasing since 1980.
To determine whether the same rate of ice loss year after year could cause such an acceleration in uplift, Compton tested that idea using mathematical models. The answer was no: The glaciers had to be melting faster and faster every year to be causing more and more uplift.
Compton found the onset of rising temperatures and the loss of ice corresponded tightly with her estimates of when uplift began.
“I was surprised how well everything lined up,” she said.
Bennett said, “There’s no way to explain that accelerated uplift unless the glacier is disappearing at an accelerated rate.”
Estimating ice loss is laborious and difficult, he said. “Our hope is we can use current GPS measurements of uplift to more easily quantify ice loss.”
The team’s next step is to analyze the uplift data to reveal the seasonal variation as the ice caps grow during the winter snow season and melt during the summer.
The National Science Foundation and the Icelandic Center for Research funded the research.
The American Geophysical Union is dedicated to advancing the Earth and space sciences for the benefit of humanity through its scholarly publications, conferences, and outreach programs. AGU is a not-for-profit, professional, scientific organization representing more than 62,000 members in 144 countries. Join our conversation on Facebook, Twitter, YouTube, and other social media channels.
Notes for Journalists
Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this article by clicking on this link:
Or, you may order a copy of the final paper by emailing your request to Nanci Bompey at email@example.com. Please provide your name, the name of your publication, and your phone number.
Neither the paper nor this press release is under embargo.
“Climate driven vertical acceleration of Icelandic crust measured by CGPS geodesy”
Kathleen Compton: Department of Geosciences, University of Arizona, Tucson, Arizona USA;
Richard A. Bennett: Department of Geosciences, University of Arizona, Tucson, Arizona USA;
Sigrun Hreinsdóttir: University of Iceland, now at GNS Science in Avalon, New Zealand.
Contact information for the authors:
Kathleen Compton: firstname.lastname@example.org
Richard Bennett: +1 (520) 621-2324, email@example.com
+1 (202) 777-7524
University of Arizona Contact:
Mari N. Jensen
+1 (520) 626-9635
Peter Weiss | American Geophysical Union
Predicting eruptions using satellites and math
28.06.2017 | Frontiers
NASA sees quick development of Hurricane Dora
27.06.2017 | NASA/Goddard Space Flight Center
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
28.06.2017 | Awards Funding
28.06.2017 | Earth Sciences
28.06.2017 | Physics and Astronomy