In one of the most remote and inhospitable regions of the world, a small research team recently returned to the icy cliffs of C.H. Ostenfeld Nunatak in Northeast Greenland to unlock the secrets of Earth’s ancient climate. The expedition, led by Peter Frykman, Senior Researcher at the Geological Survey of Denmark and Greenland (GEUS), aimed to revisit a cave system he discovered decades earlier - and to collect valuable climate data frozen in time.

What started as a personal curiosity became a deeply ambitious scientific mission, combining paleoclimate research, modern expedition logistics, and precise environmental monitoring made possible by Tinytag data loggers.

A Return to a Remote Discovery

Peter Frykman originally identified caves at C.H. Ostenfeld Nunatak back in 1977, but it wasn't until 2023 - more than 45 years later - that he was finally able to return. "Knowing that it would be very unlikely we could ever go back again due to the costs and remoteness," Frykman explains, "we brought as much equipment as we could."

The two-person team included Professor Bogdan Onac, an internationally recognised expert in cave science and paleoclimate from the University of South Florida. With funding from two private foundations, the pair flew into Greenland, chartered a helicopter already operating in the area, and set up camp at 900 metres above sea level on the icy cliffs of the Nunatak.

The Science of Ancient Climates

The scientific goal was clear: to assess the potential of the cave system as a paleoclimate archive - natural records of the Earth's climate stored in speleothems (mineral deposits) and cave ice. "These carbonate deposits carry an isotope signal that can tell us what the temperature was millions of years ago," says Frykman. "In fact, we've already dated some material to around 5 million years, a time window previously undocumented for Greenland."

Understanding these ancient climate patterns is vital for improving models that predict future Arctic conditions - especially in a region as sensitive to warming as Greenland. The expedition's findings will contribute to a broader study on Arctic speleothem formation, published in collaboration with universities and research institutes worldwide.

Documenting the Present to Understand the Past

To complement the geological samples, the team also wanted to document current microclimate conditions inside the caves. That's where Tinytag data loggers came in.

"Although we knew we'd likely never return, my colleague suggested that we just as an option install data loggers to record temperature and humidity over time," says Frykman. "That way, we could understand the present-day environment of the cave and how cave air circulation works"

Three Tinytag TGP-4500 loggers were deployed in strategic locations inside Cave N-10:

• One near the entrance
• One in a zone where frost condenses on the walls
• One in the deepest section of the cave

With a projected battery life of around 2.5 years, the loggers will collect seasonal data year-round. Once retrieved, the data will help calibrate models, explain the behaviour of ice and moisture within the cave, and provide essential context to the geological samples collected.

Why Tinytag?

The team chose Tinytag loggers based on the recommendation of Professor Onac, who has used them extensively in other cave studies. "I tested them at home before the trip," Frykman explains. "They were easy to use, and I had no trouble with the software."

While basic and non-wireless by design - ideal for low-maintenance deployments - the Tinytags still proved reliable for a scenario where remote access wasn't feasible. Frykman mentioned interest in possible future enhancements, such as wireless transmission or satellite uplinks, which could further enhance data collection from extreme locations.

Funding, Logistics, and Scientific Impact

Unlike many national research missions, this expedition was made possible by private foundation support. The Geological Survey of Denmark and Greenland supported logistical coordination, but not direct funding. "We were lucky to combine our fieldwork with helicopter operations already taking place in the area," Frykman says.

The research data and documentation will contribute to an upcoming scientific publication, currently in development. More than just an academic exercise, this work could help secure future funding for additional Arctic expeditions and raise awareness of the region's scientific importance.

What's Next for Arctic Climate Research?

The hope now is to retrieve the data loggers and add their findings to the broader body of climate research. "If we can demonstrate that caves in the Arctic can supply this kind of data, it will help justify future expeditions," says Frykman.

The expedition also revealed that more caves exist in the region than originally thought. High-resolution images captured from helicopters suggest untapped potential for further exploration - and more hidden climate records waiting to be discovered.

Supporting Science in Extreme Environments

For Tinytag and Gemini Data Loggers, it's a privilege to support missions like this. While the technology may sit quietly gathering data in some of the most extreme and silent environments on Earth, its impact echoes far beyond the cave walls - helping researchers like Peter Frykman unravel the mysteries of climate change, both ancient and modern.

Want to learn more?

You can view more of Peter's expedition via the Underground Channel video or read the summary on GEUS's LinkedIn page.