Intense two-week heatwave in Fennoscandia: hotter and more likely due to climate change

A research analysis by World Weather Attribution finds that human-induced climate change made a July 2025 heatwave in Norway, Sweden, and Finland approximately 2°C hotter and at least ten times more likely than in a preindustrial climate. The event caused significant strain on healthcare systems, disrupted reindeer grazing and Sámi livelihoods, and led to increased drowning deaths and wildfires. The report highlights that current winter-focused building designs in the Nordic region are inadequate for rising temperatures and that similar heatwaves are now twice as likely as they were during the previous major event in 2018 due to a global warming increase from 1.1°C to 1.3°C.

• Human-induced climate change increased the temperature of the 14-day heat event by approximately 2°C and made such events at least ten times more likely than in a preindustrial climate, though this likelihood is likely an underestimate.
• Due to global warming increasing from 1.1°C to 1.3°C, similar prolonged heatwaves are now estimated to be twice as likely as they were during the previous comparable event in 2018.
• Nighttime temperatures were made about 2°C hotter and 33 times more likely due to human-caused climate change.
• Under current policies, a further 1.3°C of global warming by the end of the century is projected to make such events 1.4°C warmer and five times more likely.
• The heatwave caused severe societal and environmental disruptions, including strained healthcare systems during the peak holiday season, increased drowning deaths (28 in Finland, 31 in Sweden, and 8 in Norway), wildfires in Lapland, and threats to Sámi livelihoods through disrupted reindeer grazing.
• Nordic building infrastructure is poorly adapted for heat, as winter-focused designs in care facilities and preschools often lack adequate shading and cooling systems.

APA

World Weather Attribution (2025). Intense two-week heatwave in Fennoscandia: hotter and more likely due to climate change. https://www.worldweatherattribution.org/intense-two-week-heatwave-in-fennoscandia-hotter-andmore-likely-due-to-climate-change/

Chicago

World Weather Attribution. Intense two-week heatwave in Fennoscandia: hotter and more likely due to climate change. 2025. https://www.worldweatherattribution.org/intense-two-week-heatwave-in-fennoscandia-hotter-andmore-likely-due-to-climate-change/.

Wikipedia

{{cite report |author=World Weather Attribution |title=Intense two-week heatwave in Fennoscandia: hotter and more likely due to climate change |date=14 August 2025 |url=https://www.worldweatherattribution.org/intense-two-week-heatwave-in-fennoscandia-hotter-andmore-likely-due-to-climate-change/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldweatherattribution2025intense, author = {{World Weather Attribution}}, title = {{Intense two-week heatwave in Fennoscandia: hotter and more likely due to climate change}}, institution = {World Weather Attribution}, year = {2025}, month = aug, url = {https://www.worldweatherattribution.org/intense-two-week-heatwave-in-fennoscandia-hotter-andmore-likely-due-to-climate-change/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }