News and Events

Nutrient inputs from rivers and coastal erosion are of crucial importance for marine ecosystems in the Arctic Ocean

In the Arctic Ocean, primary production by phytoplankton sustains a unique ecosystem. The availability of nutrients represents a limiting factor of this phytoplankton growth. So far, it was largely believed that these nutrients stem largely from other parts of the global ocean, such as the Atlantic or Pacific Ocean. Not well known is the role of the nutrients from land that enter the Arctic Ocean via rivers and through the erosion of coastal soils. In a study published today in Nature Communications, an international team of scientists from the IPSL in Paris, the Université Libre de Bruxelles, the ETH Zürich, and the University of Bern provides an estimate of terrestrial nutrient inputs, with riverine fluxes being based on observations at the six largest Arctic rivers and erosion fluxes being based on satellite images of the Arctic coastline and measurements of the nutrient content in these eroding soils. With a state-of-the-art high-resolution ocean-biogeochemical model, it was estimated that terrigenous nutrients sustain 28-51 % of the total Arctic Ocean productivity. This study suggests a much more prominent imprint of terrestrial inputs on the Arctic Ocean ecosystem.

Reference :

Jens Terhaar, Ronny Lauerwald, Pierre Regnier, Nicolas Gruber & Laurent Bopp, Around one third of current Arctic Ocean primary production sustained by rivers and coastal erosion, Nature Communications, 8th January 2020, 10.1038/s41467-020-20470-z.

Marine heatwaves are man-made

A study led by researchers from the Oeschger Centre for Climate Research at the University of Bern shows that heatwaves in the world’s oceans have become 20 times more likely due to human influence.

In recent years, marine heatwaves have caused considerable damage to the ecosystems in the open seas and at the coast, including increased mortality among birds, fish and marine mammals, harmful algal blooms and coral bleaching events. Researchers led by Bern-based marine scientist Charlotte Laufkötter have been investigating the question of how anthropogenic climate change has been affecting major marine heatwaves in recent decades. In a study recently published in the well-known scientific publication Science, Charlotte Laufkötter, Jakob Zscheischler and Thomas Frölicher concluded that major marine heatwaves have become more than 20 times more frequent due to human influence. While they occurred every hundred or thousand years in the pre-industrial age, depending on the progress of global warming, in the future they are set to become the norm. If we are able to limit global warming to 1.5 degrees, heatwaves will occur once every decade or century. If temperatures rise by 3 degrees, however, extreme situations can be expected to occur in the world’s oceans every year or ten years.

Anthropogenic CO2 increase is unprecedented

In a study now published in Science, led by former PhD student Christoph Nehrbass-Ahles, a series of pulse-like CO2 releases to the atmosphere was identified between 330,000 and 450,000 years ago. The measurements were carried out in a Swiss-French collaboration on
samples from the EPICA ice core from Dome Concordia in Antarctica, that was drilled from 1995 to 2005. Surprisingly, these jumps also occurred in warm periods. This provides a new context for today's anthropogenic CO2 rise that is more than six times larger and almost ten times faster than these natural jumps. The joint analysis with a marine sediment core from the North Atlantic demonstrates that these abrupt rises were always evident when melting ice masses in Greenland or Antarctica considerably disturbed the ocean circulation.

Climate crisis in ancient Rome linked to colossal volcanic eruption in Alaska

An international research team involving climate scientists from CEP published in PNAS results of a study of a major climate extreme in the Roman antiquity triggered by a massive volcanic eruption. The team used ash detected in a Greenland ice core to decipher the geochemical fingerprint of the Okmok volcano in Alaska. This allowed the researchers from CEP to perform numerical model simulations of the eruption’s global climate impact. Dated to the year 43 BCE, in the midst of the Roman Civil War, the eruption produced climate anomalies throughout the northern hemisphere and affected the Nile River flow and subsequent crop yields. The discovery will help to disentangle the complex interplay of external climatic stressors with ancient human societies, and serves as a warning of the global-scale impact of volcanic hazards in the globalized world of the 21st century.

Arctic Ocean acidification worse than previously expected

A new study in Nature led by climate scientist Jens Terhaar from CEP and colleagues from École normale supérieure in Paris shows that the Arctic Ocean will take up more CO2 over the 21st century than predicted by most climate models. This additional CO2 causes a distinctly stronger ocean acidification, which threatens the life of calcifying organisms - such as mussels and "sea butterflies" - and can have serious consequences for the entire food chain.

Anthropogenic CH4 emissions from fossil fuel sources underestimated

Two papers in Nature and Science using 14C and stable isotopes in ice core methane reveal that natural geological and permafrost CH4 emissions are much smaller than previously estimated. Consequently, anthropogenic fossil fuel CH4 loss must be larger than expected.

RADIX Team at Dome C

The unibe RADIX Team, consisting of Jakob, Remo and Thomas, is now at Dome Concordia Station (75°06'S 123°20'E, 3233 asl) after a long 10-day trip via Singapore, Christchurch, McMurdo Station, and Mario Zucchelli Station. Preparations for transfer to Little Dome C, about 33 km from Dome C, are underway. The RADIX Team is joined by Massimo, Saverio and Michele (ENEA) and Luc (IPEV) who will build the drilling tent for BeyondEPICA.

Thomas Frölicher, Laureate of the Theodor Kocher Prize 2019

Thomas Frölicher is the winner of the Theodor Kocher Prize 2019, which the University of Berne awards to its best young scientists. The award recognizes his fundamental contributions to the study of extreme events in the ocean. His research showed that as global warming continues, marine heatwaves become even more frequent, intense and widespread and have potentially large and damaging impacts on ecosystems. Further information can be found at:

KUP PhD Day 2019

On 13. June the second PhD of Climate and Environmental Physics took place. It was a full day of science during which the PhD students reported on their progress and which generated many engaged discussions and stimulating exchange. All have experienced the broad range of research and the multitude of still open questions regarding the past, present and future changes of the Earth System.

Working at East GRIP

Lucas Silva, normally measuring CO2 concentrations on Antarcitic ice samples, is working hard at EastGRIP exploring the firn layers which are crucial for his research. More seriously, Lucas is processing and logging ice cores at EastGRIP and enjoying his first experience on the ice sheet.

Working at East GRIP

Lucas Silva, normally measuring CO2 concentrations on Antarcitic ice samples, is working hard at EastGRIP exploring the firn layers which are crucial for his research. More seriously, Lucas is processing and logging ice cores at EastGRIP and enjoying his first experience on the ice sheet.

Four New EU Projects

Members of CEP are partners in four Horizon 2020 projects of the European Commission that will start in 2019. The project BEOIC, BeyondEPICA: Oldest Ice Core, has the goal to drill a 1.5-million year old ice core in Antarctica. Switzerland, through scientists of CEP, is one of the leading partners in this € 11M project.

EU Project TiPES is studying tipping points in the Earth System by combining new mathematical theories with the paleoclimatic records. Members of CEP will carry out simulations with EMICs to understand new paleoceanographic tracers.

EU Project CCICC will reduce uncertainty in our quantitative understanding of carbon-climate interactions and feedbacks. Scientists of CEP will quantify key processes regulating the coupled carbon-climate system and use observational constraints to provide long term projections of the climate in response to anthropogenic emissions.

EU Project COMFORT will determine tipping points in physical and biogeochemical tipping systems and the consequences of passing tipping points for the marine carbon, oxygen and nutrient cycles as well as for marine ecosystems. Members of CEP will assess marine extreme events and quantify maximum carbon emissions for a safe operating space.

Thomas Stocker, Member of Leopoldina

Thomas Stocker was elected member of Leopoldina, the Academy of Sciences of Germany. The Leopoldina is an association of scientists who are elected by the presidency of the Academy, at the proposition of their members. Leopoldina was founded in 1652 and is the oldest continuously existing learned society in the world. The purpose of Leopoldina is to provide the scientific view on topics of high societal relevance, independent of economic or political interests and agendas.

EPS Historic Site 2019

The European Physical Society honors the High Altitude Research Station Jungfraujoch with an award as ‘Historic Site’. In order to celebrate this award, there will be a half-day symposium on Thursday, February 7, 2019 at the University of Bern.

Detailed information on the event can be found here.

Marine heatwaves to become more frequent due to global warming

Marine heatwaves - prolonged periods of anomalously high ocean surface temperatures - are likely to become more frequent, extensive and intense as a result of global warming, according to a study led by Thomas Frölicher published now in Nature ( The study reports that the number of marine heatwave days doubled between 1982 and 2016, and this is projected to increase further if global temperatures continue to increase.

Media Release of the University of Bern, 15.8.2018

A 1.5°-2° warmer world in the future - Lessons from the past

In a paper now published online in Nature Geoscience ( an international team of researchers led by Hubertus Fischer has investigated the long-term response of the Earth System in the future using periods in climate history that were warmer than preindustrial. The study shows that marine and terrestrial ecosystems will spatially shift and sea level will rise by several meters over the next thousands of years even under strict mitigation scenarios as foreseen in the Paris Agreement. This stresses the need for climate models to include such long-term effects to forecast the full spectrum of Earth System changes to come.

Nature Geosciences, 27.6.2018

CEP PhD Day 2018

An enthusiastic group of scientists gathered at the First PhD Day of CEP to discuss ongoing projects, exchange personal experiences and foster new collaboration. This stimulating event has highlighted the breadth of our research ranging from the development of innovative analytical tools, measurement of new paleoclimatic records from ice cores and tree rings, design and application of models of the physical-biogeochemical climate system on time scales from years to a million years, and to radioisotope environmental physics.




Hubertus Fischer awarded Hans Oeschger Medal

During the last European Geosciences Union (EGU) General Assembly in Vienna Hubertus Fischer was awarded the Hans Oeschger Medal 2018. In his medal lecture he recalled the history of how rapid climate changes in the last glacial, the so called Dansgaard Oeschger events, were discovered. He summarized how latest progress in paleoclimate reconstructions and in ice core science in particular has pushed forward our understanding of the interaction of atmosphere and ocean changes in the global propagation of DO events.

EGU, 11.4.2018



Prof. Thomas Stocker receives the Marcel Benoist Swiss Science Prize 2017

By means of climate modelling and ice core analysis, Prof Stocker has been able to demonstrate the reality of climate change and its resulting consequences. In keeping with the objects of the Foundation, his research findings are of great importance to human life, and address one of the main challenges facing today’s society. Federal Councillor Johann N. Schneider-Ammann, President of the Marcel Benoist Foundation, met Professor Thomas Stocker in Bern on Friday, September 1, and congratulated him on this important award. The award ceremony will be held in Bern on 1 November.

Media Release of the University of Bern, 1.9.2017



Fortunat Joos elected AGU Fellow

The American Geophysical Union (AGU) elected Prof. Fortunat Joos to be AGU Fellow. AGU Fellows are recognized for their scientific eminence in the Earth and space sciences. This distinction recognizes Fortunat's leadership and long-term impact in global-scale carbon cycle research.

Announcement in AGU news (28.7.2017)



Hubertus Fischer and Thomas Stocker honoured by AGU

The American Geophysical Union (AGU) awarded Prof. Hubertus Fischer the 2017 Dansgaard Award for his outstanding work in paleoclimate research based on polar ice cores.

Further, Prof. Thomas Stocker was selected to hold the prestigious Cesare Emiliani lecture at the 2017 AGU Fall Meeting in New Orleans.

AGU list of 2017 awardees and named lecturers (28.6.2017)