Diver Daan Jacobs recently emerged from the icy depths of a remote Finnish lake, surfacing through a narrow opening cut into thick winter ice. His descent of eight metres revealed an extraordinary underwater landscape, where faint sunlight filtered through frozen layers and fish moved quietly among submerged rock formations.
Such scenes are rarely witnessed during the Arctic winter, when heavy snow covers the ice and temperatures can plunge to minus 40 degrees. Yet Jacobs is part of a growing cohort of specialists venturing beneath polar ice to study fragile ecosystems increasingly under threat. Earlier this month, he took part in a polar scientific diving course run by the Finnish Scientific Diving Academy in northern Finland. The programme aims to equip scientists with the technical and scientific expertise required to conduct research beneath Arctic and Antarctic ice.
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The urgency of this work is underscored by the pace of climate change. The Arctic is warming at roughly four times the global average, affecting weather systems worldwide and placing pressure on species such as polar bears, which depend on sea ice for hunting. Meanwhile, in Antarctica, melting ice sheets are contributing to rising sea levels and disrupting marine ecosystems.
Researchers say understanding what lies beneath the remaining ice is critical. However, the work demands highly specialised skills, and only a limited number of trained divers currently possess the expertise required to operate safely in such extreme conditions.
Marine biologist Erik Wurz, one of the course instructors, stressed the need for rapid expansion in research efforts. He warned that the speed of environmental change leaves little time to fully assess its consequences without significantly increasing scientific presence in polar regions.
Despite advances in robotics and artificial intelligence, experts maintain that human divers remain indispensable. British Antarctic Survey researcher Simon Morley noted that divers can collect multiple specimens with minimal disturbance, whereas mechanical methods risk damaging delicate habitats.
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Training sessions are held at the University of Helsinki’s Kilpisjärvi Biological Station, where participants undergo intensive instruction over ten days. Conditions are harsh: divers must contend not only with near-freezing water beneath ice up to a metre thick, but also biting winds and extreme cold above the surface.
For students such as Ruari Buijs from the University of Plymouth, the course offers a vital stepping stone towards careers in polar research. Others, including German research assistant Caroline Chen, see it as an opportunity to prepare for future scientific expeditions in some of the planet’s most challenging environments.
Yet for all the technical demands, participants describe the experience beneath the ice as remarkable. Sunlight streaming through frozen layers creates an otherworldly glow, offering a rare glimpse into ecosystems that remain largely hidden — but increasingly vital to understand as the planet warms.
