The hunt for the oldest ice in the world
Global greenhouse gas emissions reached a record level of 57.4 GtCO2e (gigatons of CO2 warming equivalent) in 2022, an increase of 1.2 % (0.6 GtCO2e)* compared to the previous year. Never before has such a volume of CO2 and other greenhouse gases attributable to mankind been released into the atmosphere in a single year.
*Source: Emissions Gap Report 2023 of the United Nations
No one can precisely estimate what consequences of this development await us. It is clear that the temperatures on the planet will rise due to the intensified greenhouse gas effect, and that this will drive climate change. However, higher temperatures alone are nothing new in the Earth’s history; ice ages and warmer periods have always alternated. Worrying, however, are three current trends that have never existed in this combination before: the scale and speed with which current warming is taking place, its cause based on human activity, and the fact that global warming affects a sensitive network of human societies with almost 8.2 billion inhabitants around the world.
The Intergovernmental Panel on Climate Change (IPCC) predicts global warming of 2.7 degrees by 2100 in the medium scenario*. Anticipated but already observed side effects are a rise in sea levels, record dry months in the tropics and subtropics, as well as new precipitation extremes in the northern latitudes. This will result in acidification of the oceans due to a higher CO2 concentration, which will have a harmful effect on marine organisms.
*Source: Climate change 2023 Synthesis Report, Summary for Policymakers der IPCC
Reflection on the climate history of the planet
In order to understand the cause and effect of this critical development, scientists around the world are researching the cycle of greenhouse gases. They are seeking methods through which to decode the complex climate system and better predict the reaction to sustained emissions on Earth. One of these methods is to look back at the past. Very far back in history: over more than one million years. 800,000 to 1.2 million years ago – as has been revealed by sediment drilling in the deep sea – there was a shift in the regularity of the ice ages. While the ice ages and warm periods on the planet have alternated every 100,000 years on average for the past 800,000 years, 1.2 million years ago the cycle stood at 40,000 per phase. What led to this? And what influence do atmospheric CO2 and other greenhouses gases have on this change?
The only direct information source available to them is drilled ice cores from Antarctica.
To find answers to these questions, scientists are looking for a possibility to reconstruct continuous climate data – in particular the greenhouse gas concentrations – for this transition. Unlike other climate archives, such as corals, tree rings and stalagmites, ice contains air bubble inclusions and therefore a direct archive of the atmospheric composition from this era. The challenge is making this research usable.
Climate retained in Antarctic ice
Beyond EPICA – Oldest Ice Core is the name of the European research project dedicated to this task. Scientists from ten countries are together drilling the oldest stratified ice in the world. The aim is to retrieve a 1.5 million year old ice core in Antarctica, and analyze it in the lab. Drilled ice cores from the South Pole region are the most reliable information sources when it comes to investigating climatic fluctuations and changes in the composition of the atmosphere in the past, as well as their causes.
In the gases trapped in the ice, in the isotopic composition of the water and the aerosol particles dissolved in it, the researchers find unique quantitative information about the climate and atmospheric reactions from the Pleistocene period. With the help of these facts, other researchers could further improve their climate models and use computer simulations to formulate their forecasts for the future much more precisely and long-term and run scenarios such as: What happens to the oceans, ice shields, the eco system and vegetation if the planet’s climate permanently increases by two, four or six degrees?
The basis for this analysis is the air trapped inside the ice cores. Even a sample of just a few milliliters can be used to measure numerous constituents that are also contained in our air today. Their analysis can provide information on how high the oxygen levels on the planet were more than one million years ago, what the concentrations of greenhouse gases such as carbon dioxide, nitrous oxide or methane were at that time, and even the sources of these gases. In turn, these results allow us to draw conclusions on the correlation between the greenhouse gas concentration and climate change. This provides the researchers with a key through which to recognize the relevant connections between the carbon cycle, the ice sheet, the atmosphere and the behavior of the seas.
How do you find the oldest ice in the world?
One of the key players in the Oldest Ice Initiative is Prof. Hubertus Fischer of the Oeschger Centre for Climate and Climate Change Research at the University of Bern. At the turn of the millennium, he worked together with European partners in the eastern Antarctic to recover and analyze the oldest ice core investigated at that time, which was 800,000 years old. Because the results of that investigation revealed interesting connections, they wish to look back even further into the past and decipher the mystery of the changing ice age cycles.
The ice core researchers have been drilling at Little Dome C, a suitable drilling point only around 40 kilometers from Dome Concordia, since 2022. With the help of complex flow models, glaciological and geophysical investigations on the ground and a myriad of radar flights, the team was able to locate this drilling point, which promises 1.5 million-year-old ice. The actual drill core has a diameter of ten centimeters. At least one drill core of this size is necessary to obtain sufficient sample material for the analyses, as the really interesting part of the ice core will be its lower 300 meters. Here the ice is extremely compacted, so that 10-40,000 years of climate history can be stored in one meter of drill core. Because of that, the researchers are planning to drill a second parallel core for the lowest 300 meters in order to obtain more sample material for all the complex analyses.
The project has recently reached a major milestone: The rock bed at Little Dome C has been reached and an ice core has already been drilled that contains at least 1.2 million years of climate history. The deep ice (the lowest approx. 400 m) will then be drilled again in the coming 2025/26 season. This will be done by means of so-called “deviational drilling”.
Each sample used as efficiently as possible
This also explains why the Bern ice core group around Hubertus Fischer is working so intensively on an entirely new analysis method. During the last years now they developed a pioneering apparatus, which they use to release air from the ice with infrared laser sublimation, without contaminating it. This is necessary in order that it can be subsequently analyzed with the aid of laser absorption spectrometry. Using this method, it is possible to measure all greenhouse gases from a sample size of ca. 15 grams – and the extracted air remains available for further measurements. This form of “sample recycling” is important because a number of research laboratories want to investigate the oldest ice in the world – and not every analysis is possible with such a small quantity.
A long route from Antarctica to the lab
Huge logistical effort and financial outlay are required before the ice can be analyzed in the laboratory: The initial non-destructive measurements must first be performed at the drilling site, after which the ice core is sawed into meter-long sections and packed in insulated boxes. These are then flown by aircraft to the coast of Antarctica. From here, the transport boxes will travel in a special -50 °C deep-freeze container to Europe by ship, where they will be distributed among the participating labs in ten countries. Immense logistical effort and cost with the use of numerous vehicles and extensive technology, energy and personnel. The estimated costs for the overall European project come to over 15 million euros, with a large part being provided by the EU research program HORIZON 2020 and the Swiss National Science Foundation.
Great expectations for the research results
A long and arduous journey that could pay dividends for all the world’s inhabitants. There are numerous interested parties around the globe, who have high expectations with respect to the results of this research project. Climate scientists, geologists, glaciologists and many other natural scientists are hoping for new information on how our climate system works and with which they can further improve their current climate models and derive more accurate predictions for the future.
It is expected that the findings will further reduce our leeway in terms of delays in the global efforts to reduce greenhouse gas emissions.
A portrait: University of Bern
What does the climate have to do with our society? Researchers at the University of Bern want to fully answer this question.
The Oeschger Centre for Climate and Climate Change Research (OCCR) at the University of Bern is a leading international center for climate research. In interdisciplinary research groups from 17 institutes and five faculties, the fields of physics, geography, biology, chemistry, history, economics, health, political sciences and philosophy are linked with each other to facilitate an understanding of the complex system Earth, and to find answers to the pressing questions facing mankind. One of the most urgent is: What effects can humankind, society and nature expect, if the climate continues to change so dramatically? The Bern climate physicist Prof. Hubertus Fischer is significantly involved in this. His field of expertise is ice core research.
Prof. Fischer, why are you as a physicist so interested in old ice cores?
When studying physics I was initially primarily interested in astrophysics, particle physics and biophysics. However, when seeking a topic for my dissertation, my subsequent mentor at Heidelberg University asked me whether I would consider going on an expedition to Greenland.So we set off with snowmobiles, piste vehicles and tents, to drill ice cores as climatic and environmental archives – and that is when I was captivated by ice.
I did not have to think for very long because I have always had a fondness for landscapes of snow and ice.
What do you find so fascinating about working in ice and snow?
The absence of landscape and any stimulus on the ice is fascinating and balances me inwardly. I function well in this peace and quiet, and I love the clear view right to the horizon. Also because the sun often shines on the Antarctic ice shield. My longest time there was over three months, during ice core drilling. Furthermore, I am excited about the unique opportunity to study the atmosphere of the past using the tiny air bubbles.
What is this type of overnight camp in the Antarctic actually like?
The researchers sometimes sleep in tents, but there are also some living containers. The coldest outside temperature I have experienced in a tent was -46 °C. With the right sleeping bag it is not an issue, it is still warm and cozy. The camps at the major deep drilling rigs for ice cores have heated containers, which contain restrooms, showers and a kitchen. When on expeditions without permanent infrastructure it is still possible to take a snow wash in the sun, e.g. in “warmer” areas such as Greenland where it only goes down as far as -30 °C. When working outdoors or in the big “caves” beneath the snow where we carry out the deep drilling and perform the first analyses, we wrap up in warm downy gear. Unfortunately, I almost always have cold hands anyway.
Do you have a favorite place in the ice?
Entirely spontaneously, I would say: Greenland. Probably because my first expedition took me there and I was totally captivated, and because people live there who have long since learned to cope with these inhospitable conditions. . But in actual fact the polar ice deserts are so similar that it would be difficult to see any difference at all with the naked eye. If I were to be abandoned in the middle of the Greenland or Antarctic ice shield, I would need my analysis equipment to determine - on the basis of the snow and ice constituents - whether I was in the Arctic or the Antarctic.
Your methods of analysis are an in-demand discipline of the ice core researchers of the University of Bern. What is special about them?
We are among the world’s leading specialists when it comes to the concentration and isotope analysis of atmospheric air in drilled ice cores. Only in Bern are we so far able to extract all the greenhouse gases contained in ice cores and determine the complete bandwidth of their isotopic composition. Furthermore, in past years we have developed a mass spectrometry method for measuring the noble gas ratio and the isotopic composition of the noble gases in ice core samples, which provides us with quantitative information on the change in mean ocean temperature.
Further information
- General information about the Oldest Ice Core Project: https://www.beyondepica.eu/en/
- Latest article about the successful ice core drilling: https://www.beyondepica.eu/en/news-events/press-releases/
- Oeschger Centre for Climate Change Research (OCCR): https://www.oeschger.unibe.ch/index_eng.html
Do you want to know more? Read the first article regarding the Oldest Ice Core Project in our Elements Magazine no. 1.
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Get some further impressions in our corporate video
In our corporate video "As simple as life" you get an impression about our company and focus, for which ice core drilling at the research station of the University of Bern on the Swiss Jungfraujoch was reconstructed. Drilling for the Oldest Ice Core Project in Antarctica is set to take place under significantly harsher conditions.
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