At
The Helmholtz Association of German Research Centres(DE)
1.18.23
Rivers of meltwater (Greenland’s ice sheet).
Ice core from the study.
At high elevations of the Greenland Ice Sheet, the years 2001 to 2011 were 1.5 °C warmer than in the 20th century and represent the warmest decade in the last thousand years.
A temperature reconstruction from ice cores of the past 1,000 years reveals that today’s warming in central-north Greenland is surprisingly pronounced. The most recent decade surveyed in a study, the years 2001 to 2011, was the warmest in the past 1,000 years, and the region is now 1.5 °C warmer than during the 20th century, as researchers led by the Alfred Wegener Institute just report in the journal Nature [below]. Using a set of ice cores unprecedented in length and quality, they reconstructed past temperatures in central-north Greenland and melting rates of the ice sheet.
The Greenland Ice Sheet plays a pivotal part in the global climate system. With enormous amounts of water stored in the ice (about 3 million cubic kilometres), melt and resulting sea-level rise is considered a potential tipping point. For unmitigated global emissions rates (‘business as usual’), the ice sheet is projected to contribute up to 50 centimetres to global mean sea-level by 2100. Weather stations along the coast have been recording rising temperatures for many years. But the influence of global warming on the up to 3,000 m elevated parts of the ice sheet have remained unclear to due to the lack of long-term observations. In a study now published in Nature [below], experts from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) present clear evidence that effects of global warming have reached the remote, high-elevation areas of central-north Greenland.
“The time series we recovered from ice cores now continuously covers more than 1,000 years, from year 1000 to 2011. This data shows that the warming in 2001 to 2011 clearly differs from natural variations during the past 1,000 years. Although grimly expected in the light of global warming, we were surprised by how evident this difference really was,” says AWI glaciologist Dr Maria Hörhold, lead author of the study. Together with colleagues from AWI and the University of Copenhagen’s Niels Bohr Institute, she analyzed the isotope composition in shallow ice cores gathered in central-north Greenland during dedicated AWI expeditions.
Previous ice cores obtained at co-located sites starting in the 1990s, did not indicate clear warming in central-north Greenland, despite rising global mean temperatures. Part of the reason is substantial natural climate variability in the region.
The AWI researchers have now extended the previous datasets up to winter 2011/2012 by a dedicated redrilling effort, recovering time series unprecedented length and quality. The temperatures were reconstructed by using consistently one single method for the entire record in the lab: measuring concentrations of stable oxygen isotopes within the ice, which vary with the temperatures prevailing at times of ice formation. Previous studies had to draw on a range of different climate archives and combine results to reconstruct temperature, introducing much larger uncertainties in the assessment of natural variability.
In addition to the temperature, the team reconstructed the melt production of the ice sheet. Melting has increased substantially in Greenland since the 2000s and now significantly contributes to global sea-level rise. “We were amazed to see how closely temperatures inland are connected to Greenland-wide melt water drainage – which, after all, occurs in low-elevation areas along the rim of the ice sheet near the coast,” says Maria Hörhold.
In order to quantify this connection between temperatures in high-elevation parts and melting along the edges of the ice sheet, the authors used data from a regional climate model for the years 1871 to 2011 and satellite observations of ice-mass changes for the years 2002 to 2021 from the GRACE/GRACE-FO gravimetry missions.
This allowed them to convert the temperature variations identified in the ice cores into melting rates and provide estimates for the past 1,000 years. This represents an important dataset for climate research: better understanding of the melt dynamics of the ice sheet in the past improves projections of related future sea-level rise; reduced uncertainties in projections is one step to help optimize adaptation measures.
Another exciting finding from the study: the climate of the Greenland Ice Sheet is largely decoupled from the rest of the Arctic. This could be shown in comparison with the Arctic-wide temperature reconstruction ‘Arctic 2k’. Although ‘Arctic 2k’ [Scientific Data (below)] is an accurate representation of the circumpolar region, it does not reflect the conditions in central Greenland. “Our reconstruction now offers a robust representation of temperature evolution in central Greenland, which has proven to have a dynamic of its own,” says Prof. Thomas Laepple, AWI climate researcher and co-author of the study. “Actually, we had expected the time series to strongly covary with the warming of the Arctic region,” Laepple reports. But the authors have an explanation for these differences: the ice sheet is several kilometres thick; because of its height, Greenland is more affected by atmospheric circulation patterns than other parts of the Arctic. Temperature time series on the Arctic with regional resolution are needed, says Laepple, in order to reliably describe climate change in the Arctic.
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The Alfred Wegener Institute of Polar and Marine Research in Bremerhaven, Germany. Building near the Old Port in the city. Credit: Garitzko 5 August 2007
The Alfred Wegener Institute – Helmholtz Centre for Polar and Marine Research [Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar-und Meeresforschung](DE) is located in Bremerhaven, Germany, and a member of the Helmholtz Association of German Research Centres. It conducts research in the Arctic, the Antarctic, and the high and mid latitude oceans. Additional research topics are: North Sea research, marine biological monitoring, and technical marine developments. The institute was founded in 1980 and is named after meteorologist, climatologist, and geologist Alfred Wegener.
The institute has three major departments:
Climate System Department, which studies oceans, ice and atmosphere as physical and chemical systems.
Biosciences Department, which studies the biological processes in marine and coastal ecosystems.
Geoscientific Department, which studies climate development, especially as revealed by sediments.
The Helmholtz Association (DE)
The Helmholtz Association of German Research Centers (DE) is the largest scientific organization in Germany. It is a union of 18 scientific-technical and biological-medical research centers. The official mission of the Association is “solving the grand challenges of science, society and industry”. Scientists at Helmholtz therefore focus research on complex systems which affect human life and the environment. The namesake of the association is the German physiologist and physicist Hermann von Helmholtz.
The annual budget of the Helmholtz Association amounts to €4.56 billion, of which about 72% is raised from public funds. The remaining 28% of the budget is acquired by the 19 individual Helmholtz Centres in the form of contract funding. The public funds are provided by the federal government (90%) and the rest by the States of Germany (10%).
The Helmholtz Association was ranked #6 in 2020 by the Nature Index, which measures the largest contributors to papers published in 82 leading journals.
Members of the Helmholtz Association are:
Alfred Wegener Institute for Polar and Marine Research (Alfred-Wegener-Institut für Polar- und Meeresforschung, AWI), Bremerhaven
Helmholtz Center for Information Security, CISPA, Saarbrücken
German Electron Synchrotron (Deutsches Elektronen-Synchrotron, DESY), Hamburg
German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ), Heidelberg
German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, DLR), Cologne
German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen; DZNE), Bonn
Forschungszentrum Jülich (FZJ) Jülich Research Center, Jülich
Karlsruhe Institute of Technology (Karlsruher Institut für Technologie, KIT), (formerly Forschungszentrum Karlsruhe), Karlsruhe
Helmholtz Center for Infection Research, (Helmholtz-Zentrum für Infektionsforschung, HZI), Braunschweig
GFZ German Research Center for Geosciences (Helmholtz-Zentrum Potsdam – Deutsches GeoForschungsZentrum GFZ, Potsdam
Helmholtz-Zentrum Hereon Geesthacht, formerly known as Gesellschaft für Kernenergieverwertung in Schiffbau und Schiffahrt mbH (GKSS)
Helmholtz München German Research Centre for Environmental Health (HMGU), Neuherberg
GSI Helmholtz Center for Heavy Ion Research (GSI Helmholtzzentrum für Schwerionenforschung), Darmstadt
Helmholtz-Zentrum Berlin for Materials and Energy (Helmholtz-Zentrum Berlin für Materialien und Energie, HZB), Berlin
Helmholtz Center for Environmental Research (Helmholtz-Zentrum für Umweltforschung, UFZ), Leipzig
MPG Institute of Plasma Physics (Max-Planck-Institut für Plasmaphysik, IPP), Garching
Max Delbrück Center for Molecular Medicine in the Helmholtz Association (Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft, MDC), Berlin-Buch
Helmholtz-Zentrum Dresden-Rossendorf (HZDR) formerly known as Forschungszentrum Dresden-Rossendorf (FZD) changed 2011 from the Leibniz Association to the Helmholtz Association of German Research Centers, Dresden
Helmholtz Center for Ocean Research Kiel (GEOMAR) formerly known as Leibniz Institute of Marine Sciences (IFM-GEOMAR)
Helmholtz Institutes are partnerships between a Helmholtz Center and a university (the institutes are not members of the Helmholtz Association themselves). Examples of Helmholtz Institutes include:
Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, established in 2017
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