OCCR researchers contribute to new PAGES Working groups

The PAGES (Past Global Changes) network coordinates research on past environmental and climate change worldwide. Founded in 1991 by Hans Oeschger, after whom the Oeschger Centre is named, PAGES has longstanding historical ties to the University of Bern and the OCCR in particular.

Four newly established international working groups within PAGES are closely connected to researchers at OCCR, deepening those ties even further. They bring together researchers from across disciplines and continents to address central methodological and conceptual challenges in paleosciences.

IMPACT: Investigating Climate Tipping Points

The working group Investigating Modes of Past Abrupt Climate Change and Tipping Points (IMPACT), co–led by Prof. Frerk Pöppelmeier, head of the OCCR’s Global Biogeochemical Modelling group, focuses on tipping behaviour and abrupt transitions in past Earth systems. The working group combines paleoclimate reconstructions with modelling approaches to better constrain thresholds, feedbacks and potential cascading effects within the climate system.

The group’s kickoff meeting, scheduled for May 2026 in Bern, Switzerland, will provide a first coordinated assessment of thresholds, abrupt climate changes and tipping points in Earth’s geological past across multiple temporal and spatial scales. Grounding discussions of tipping elements in empirical evidence from past climate transitions strengthens the scientific basis for understanding long term climate risks.

“The coordinated synthesis of data and models will improve how results are communicated to stakeholders, policymakers and international assessment processes such as the IPCC,” says Pöppelmeier. “In this way, the project contributes to strengthening evidence-based climate policy making .”

MPT: Major Climate Shift in Earth’s History

The Middle Pleistocene Transition (MPT) working group brings together ice-core scientists, marine and terrestrial proxy specialists, and climate, carbon-cycle, and ice-sheet modelers to better understand the mechanisms driving climate changes over the Middle Pleistocene Transition. A key participant connected to the University of Bern is Prof. Hubertus Fischer, Head of the OCCR’s Past Climate and Biogeochemical Studies group, whose expertise in ice-core research and especially greenhouse-gas reconstructions on the first ice core covering the MPT (Beyond EPICA Oldest Ice) contributes significantly to the group’s objectives.

Hubertus Fischer explains: “The working group addresses one of the great unresolved questions in paleoclimate science: why glacial cycles changed fundamentally between roughly 1.25 and 0.7 million years ago, shifting toward longer and more intense ice ages. Bringing together the latest results from ice core research with other archives and climate models, we have a fair chance to crack the case.”

The group’s kickoff meeting will take place at the Department of Earth Sciences and Clare College, University of Cambridge, UK, from 08 - 10 September 2026.

CFRAME: Improving Climate Field Reconstructions

The working group Climate Field Reconstructions and Methods Intercomparison (CFRAME), co–led by Dr. Jörg Franke, a Senior Scientist at the OCCR’s Climatology group, focuses on improving climate field reconstructions derived from natural archives such as tree rings, ice cores and sediments. Systematic comparison of reconstruction methods and integration of proxy data within climate model simulations aims to reduce uncertainties in long-term climate variability.

“CFRAME will systematically compare existing climate field reconstructions spanning the past centuries.  It will highlight areas of high confidence for users of these reconstructions.  In regions of disagreement, CFRAME will investigate the underlying causes and recommend the most suitable dataset for individual research questions,” explains Franke.

PaleoIMAGING: Developing Standards for High-Resolution Imaging

The working group PaleoIMAGING, co-led by Dr. Petra Zahajská, a Postdoctoral Researcher at the OCCR’s Lake Sediment and Paleolimnology group, develops community standards for advanced, non-destructive imaging techniques applied to environmental archives at very high temporal resolution.

PaleoIMAGING seeks to harmonise workflows in methodologies such as micro-X-ray fluorescence or hyperspectral imaging, establish shared data formats and support international training activities. Zahajská adds: “Improved comparability and long-term usability of imaging datasets help build research infrastructure that benefits the wider scientific community.”
 

Coordinated Scientific Structures and Long-Term Perspectives

Taken together, these working groups illustrate how international research networks evolve to address scientific questions and methodological developments. “The emphasis lies on coordination across various disciplines, comparability and long-term usability of data rather than on isolated individual projects”, says Martin Grosjean, OCCR Director and PAGES Co-chair.

Researchers affiliated with the OCCR contribute leadership and expertise within PAGES, helping shape collaborative frameworks that extend well beyond national boundaries. In this way, the focus remains on strengthening international scientific cooperation and ensuring that paleoscience research continues to evolve in a structured and forward-looking manner. Martin Grosjean: “These working groups exemplify the OCCR’s strength in linking empirical evidence with Earth-system modeling and reinforce Bern’s prominent role in international paleoscience research coordinated through PAGES.”