Innovative Swiss technology for analyzing the oldest ice

Air and gas concentrations in 1,5 million year old cores to be precisely measured by the University of Bern and EMPA

Ice: the measurement of a freshly drilled ice core in the context of the "Beyond EPICA" project of the European Union (Photo: PNRA and IPEV)
Measurement of a freshly drilled ice core in the context of the European Union's Beyond EPICA Project
(Photo: PNRA and IPEV)

Ice cores are a unique climate archive. Thanks to a new method developed by researchers at theUniversity of Bern and EMPA, concentrations of greenhouse gases in 1,5-million-year-old ice can be measured even more precisely.
The project "Beyond EPIC" ofXNUMX-XNUMX business days, in which the university based in the Swiss capital also participates, aims to recover these ancient ices in Antarctica.

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Ice: The team led by Lukas Emmenegger, Head of the Department "Air Pollutants/Environmental Technology" at EMPA, has developed a new laser spectrometer capable of measuring greenhouse gases on a sample of just 1,5 milliliters of air: at At the same time, a new sublimation extraction system was designed and built for this activity at the University of Bern, which allows such small air samples to be obtained continuously and without contamination from an ice core
The team led by Lukas Emmenegger, Head of the Department "Air Pollutants/Environmental Technology" at EMPA, has developed a new laser spectrometer capable of measuring greenhouse gases on a sample of just 1,5 milliliters of air: at the University of Berne, a new sublimation extraction system was designed and built in parallel for this activity, which allows such small air samples to be obtained continuously and without contamination from an ice core
(Photo: KUP/University of Bern)

In 2025 under 2.700 meters as part of the European consortium "Beyond EPICA - Oldest Ice"

The search for the oldest ice sheets preserved on planet Earth has taken an important step forward.
The “Beyond EPICA – Oldest Ice” project, a European consortium including Universität Bern, completed its second field season at the end of January 2023.
The drilling reached a depth of 808 meters.
The goal of the project is to look back XNUMX million years and obtain data on temperature trends, atmospheric composition and the carbon cycle over time.
It is necessary to reach a depth of approximately 2.700 meters in the Antarctic ice sheet and recover an ice core.
If all goes as planned, this should happen in 2025.
Only then will the complex analysis of the older ice contained in these core samples follow, for which new methods are currently being developed.

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Ice: Chopped ice cores from Project "Beyond EPICA" are ready to be transported to Europe
The chopped ice cores of the “Beyond EPICA” Project are ready to be transported to Europe
(Photo: Robert Mulvaney/PNRA and IPEV)

At the center the study of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)

The University of Bern plays a crucial role in the development of new analytical technologies.
The team led by Hubertus Fischer, Professor of Experimental Climate Physics and member of the Oeschger Center for Climate Change Research, in collaboration with EMPA, succeeded in developing a new technique for jointly measuring the greenhouse gas carbon dioxide (CO2) , methane (CH4) and nitrous oxide (N2O), as well as the carbon isotopic composition of CO2.
The ice sample needed for this purpose has a thickness of just one centimeter, therefore very small indeed, yet it is possible to obtain the maximum precision in the measurement.
“These are important prerequisites”, explains Hubertus Fischer, “to obtain high-precision, high-resolution recordings of ancient ice required by the Beyond EPICA project”.
In 1,5 million year old ice, 15.000-20.000 years of climate history are compressed into a single meter of core drilling, which places completely new demands on sample analysis.
Ice cores are an extremely important climate archive, because they alone contain past air, which allows us to directly measure past greenhouse gas concentrations.

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Ice: the “Beyond EPICA - Oldest Ice” project, a European consortium including Universität Bern, completed its second field season at the end of January 2023: drilling at the Little Dome C Antarctic site reached a depth of 808 meters
The “Beyond EPICA – Oldest Ice” project, a European consortium including Universität Bern, completed its second field season at the end of January 2023: drilling at the Little Dome C Antarctic site reached a depth of 808 meters
(Photo: PNRA and IPEV)

A perfect recirculation of precious samples thanks to the unprecedented extraction by sublimation

The new method has just been featured in the journal Atmospheric Measurement Techniques.
The Bern group worked closely with researchers from the Federal Materials Testing and Research Laboratory on the technical development of this method.
The team led by Lukas Emmenegger, Head of EMPA's “Air Pollutants/Environmental Technology” Department, has in fact developed a new laser spectrometer capable of measuring greenhouse gases on a sample of just 1,5 milliliters of air.
“Achieving such high precision in such small samples has been virtually unimaginable for a long time. We are proud that this allows valuable ice cores to be analysed”Emmenegger says.
At the University of Bern, in turn, a new sublimation extraction system was designed and built, which allows such small air samples to be obtained continuously and without contamination from an ice core.
“Thanks to this pioneering work”, says Hubertus Fischer, “it will be possible to make greenhouse gas measurements with the necessary precision and temporal resolution in really old ices”.

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Ice: The Laser Spectrometer developed by EMPA, in the background, with an automatic inlet system for the air samples of the ice cores, in the foreground: the air extracted from the old ice can be analyzed without destroying the sample, so that can be used later for further analysis
The Laser Spectrometer developed by EMPA, in the background, with an automatic inlet system for the air samples of the ice cores, in the foreground: the air extracted from the old ice can be analyzed without destroying the sample, so that it can use later for further analysis
(Photo: PNRA and IPEV)

The air is (re)frozen at -258 degrees Celsius during the continuous sublimation process

Thanks to the sublimation technique developed by the University of Bern, an ice sample can be transformed slowly from top to bottom from a solid to a gaseous state.
Individual samples are collected with centimeter resolution by freezing air at -258°C during the continuous sublimation process.
This technique guarantees one hundred percent extraction efficiency.
Another advantage of the method: The air extracted from the ice samples is not lost during the measurement in the laser spectrometer, but can be used for further subsequent analyses.
Hubertus Fischer talks about “perfect recycling” and states that “the enormous amount of work we have to devote to the analysis would never be justifiable for an ordinary ice core”.
However, it is for the ice of 1,5 million years ago, since the amount of water cooled to a solid state that is so old is extremely limited.
Hubertus Fischer received a grant for this cutting-edge research from the European Research Council (“ERC Advanced Grant”) and project funding from the Swiss National Science Foundation to implement these innovative developments.

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Ice: Hubertus Fischer is Professor at the Institute for Experimental Climatic Physics at the University of Bern and is a member of the Oeschger Center for Climate Change Research
Hubertus Fischer is Professor at the Institute for Experimental Climatic Physics at the University of Bern and is a member of the Oeschger Center for Climate Change Research
(Photo: KUP/University of Bern)

Drilling campaign in extreme weather conditions directed by Hubertus Fischer

Hubertus Fischer is one of the protagonists of the project “Beyond EPICA – Oldest Ice”.
The ice core analysis of this research initiative should contribute to a better understanding of the alternation between warm periods and ice ages.
About a million years ago, there was a dramatic shift in this climatic push-and-pull, as marine sediment studies show.
In the period before about 900.000 years ago, ice ages and warm phases alternated every 100.000 years, then only every XNUMX years.
Why this change is a mystery, but climate researchers suspect that greenhouse gases, among other things, played a crucial role.
This hypothesis will now be investigated by ice core in Antarctica, which is almost twice as old as the oldest Antarctic core analyzed so far…
In the project's second drilling season, which has just ended, the international team worked for two months in extreme conditions.
The business experienced unforeseen setbacks, such as repairs to the drilling system and delays due to bad weather conditions. Drilling is carried out in two shifts of 16 hours of work.
The Little Dome C drilling site is located 34 kilometers from the Franco-Italian research station Concordia.
At this base station of the expedition, the two Bernese researchers Markus Grimmer and Florian Krauss took care of cutting the ice cores into transportable pieces using a special saw developed by the University of Bern.

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The innovative Little Dome C ancient ice drilling site at the South Pole

Ice: as part of the European project "Beyond EPICA - Oldest Ice", the oldest ice in the world is being drilled: the Little Dome C field in Antarctica, where EMPA and the University of Bern operate, located 34 kilometers from the Franco-Italian research station Concordia (Photo: PNRA and IPEV)
As part of the European project "Beyond EPICA - Oldest Ice", the oldest ice in the world is being drilled: the Little Dome C field in Antarctica, where EMPA and the University of Bern operate, is located at 34 kilometers from the Franco-Italian research station Concordia (Photo: PNRA and IPEV)