A study has found that warming global temperatures are causing irreversible bleaching in certain Arctic lichen species, posing a threat to carbon storage and the Arctic food chain
By Khadeejah Masud
A new study, conducted by researchers from the University of Edinburgh and the British Antarctic Survey, has revealed that climate change is bleaching a lichen species that grows exclusively in circumpolar Arctic and subarctic regions.
The planet’s average surface temperature has risen about one degree since the late 19th century – and though it may seem an inconsiderable amount to the average person, this has caused a significant change in our biosphere.
Lichens are symbiotic organisms, a fusion between fungi and algae. The lichen at risk of permanent bleaching is known as Cetrariella delisei — responsible for its vital role in the world’s carbon dioxide storage, despite being so small and sparse.
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Rising temperatures are linked to destructive ecological impacts, posing a silent threat to fragile ecosystems. The tundra encompasses approximately 10-20 per cent of Earth’s land surface, and it is responsible for storing 1.4 to 1.6 trillion metric tons of carbon in its permafrost soils – roughly double the amount of carbon currently in the Earth’s atmosphere.
The study was conducted in the Arctic archipelago of Svalbard, one of the fastest-warming regions on Earth, where temperatures are rising up to seven times faster than the global average.
Researchers investigated how lichens responded to sustained temperature increases over nine years, using plexiglass enclosures to simulate warmer conditions. They monitored whether the lichens underwent bleaching, finding a visible loss of the algal symbiont and colour change linked to declining health and reduced photosynthetic activity.
A breakdown of symbiotic relationships through climate-driven bleaching is also well known in corals, where rising ocean temperatures cause corals to lose the algae they depend on to survive. As recently as 2025, the Great Barrier Reef experienced its sixth mass bleaching since 2016. Coral bleaching occurs for the same reason as lichen bleaching; it is a stress response that expels algae, which provides the vibrant colour that give the coral 90 per cent of its energy. This significantly reduces the quality of marine biodiversity.
The findings suggest that this response may be driven by gradual, long-term increases in temperature, rather than short-term extreme weather events — even though certain coral bleaching cases have been linked to extreme events such as La Niña.
The future resilience of Arctic tundra ecosystems is precarious, as the Arctic is warming faster than the global average. Even small temperature increases can accumulate and push species beyond their limits.
Lichens are also a vital part of the Arctic food chain – large mammals such as reindeer and oxen, as well as small insects like mites, are reliant on this food source. Lichen loss not only affects soil stability but also the very nutrient cycling itself, including the availability of forage for herbivores to consume
Lead author from the School of Geosciences at the University of Edinburgh, Jiříl Šubrt, said: ‘Our findings underline the importance of long-term ecological monitoring.’ His ultimate takeaway was that ‘lichens can take some time to respond to changes in temperature. The visible damaging changes illustrate that organisms that are thought to be resilient might be endangered.’
