Executive summary
Record-breaking temperatures in Iceland and Greenland during 2025 marked an unprecedented heat event for parts of the North Atlantic and Arctic regions. World Weather Attribution analysis finds that human-caused climate change made such extreme warmth far more likely and more intense. The event challenged ecosystems, infrastructure and societies adapted to cold conditions, illustrating how rapid warming is reshaping climate risk even in regions historically considered insulated from heat extremes.
What happened
In 2025, Iceland and Greenland experienced periods of unusually high temperatures, with records broken at multiple locations. Temperatures rose well above seasonal norms, affecting both populated areas and sensitive natural environments.
The heat contributed to accelerated glacier and ice melt, thawing of permafrost and stress on ecosystems adapted to cold conditions. Infrastructure such as roads, buildings and energy systems, designed primarily for cold resilience, experienced strain under sustained warmth.
What the attribution analysis found
World Weather Attribution finds that climate change played a decisive role in the observed heat extremes. Rising global temperatures have shifted the baseline climate in the Arctic and sub-Arctic, making record-breaking heat events significantly more likely than in a pre-industrial climate.
The analysis shows that the temperatures recorded during the 2025 event would have been extremely unlikely without human-induced warming. Even relatively small increases in average temperature have translated into large increases in the probability of extreme heat in these regions.
Confidence in the attribution is high, as temperature extremes respond strongly and directly to global warming.
Impacts on cold-adapted ecosystems and infrastructure
A key finding of the study is that impacts were amplified by limited adaptation to heat. Ecosystems adapted to cold conditions experienced stress, with implications for biodiversity, fisheries and traditional livelihoods.
Infrastructure vulnerability was also evident. Thawing permafrost undermined foundations, while roads and buildings not designed for high temperatures suffered damage or reduced performance.
How climate attribution fits into Arctic risk reporting
Climate attribution helps clarify how climate change is transforming risks in cold regions. By linking observed extremes directly to global warming, attribution demonstrates that Arctic and sub-Arctic regions are not only warming faster than the global average but are also becoming increasingly exposed to heat-related hazards.
This challenges assumptions that climate risks in these regions are dominated solely by cold extremes.
Why this matters for organisations
For governments, infrastructure operators, energy companies and insurers operating in Iceland and Greenland, the findings underscore rapidly growing exposure to climate risks outside historical experience. Heat-related impacts on infrastructure, ecosystems and supply chains are becoming increasingly relevant alongside ongoing cold-related risks.
How to use this in your own risk work
Organisations should incorporate climate-adjusted temperature extremes into risk assessments for cold regions, review infrastructure design standards and assess cascading risks linked to ice and permafrost melt. Planning for heat extremes should now be considered an essential component of Arctic climate resilience.
Source
World Weather Attribution (2025). Climate change drives record-breaking heat in Iceland and Greenland, challenging cold-adapted ecosystems and societies.
https://www.worldweatherattribution.org/climate-change-drives-record-breaking-heat-in-iceland-and-greenland-challenging-cold-adapted-ecosystems-and-societies/