Search Climate Insights Directory

The July 2021 floods in Western Europe were driven by extreme rainfall from the low-pressure system 'Bernd', compounded by pre-existing wet soil conditions. While attribution for small catchments like the Ahr and Erft is challenging due to high natural variability, a broader 'Pooling Region' analysis indicates that climate change increased the intensity of maximum 1-day rainfall by 3-19% and its likelihood by a factor of 1.2 to 9 compared to a climate 1.2 °C cooler. Future projections suggest further increases in intensity and frequency in a 2 °C warmer climate.

The report concludes that the prolonged regional heat in Siberia from January to June 2020 was effectively impossible without human influence, with a best estimate probability ratio of 99,000 compared to a 1900 climate. Such events would have been at least 2°C cooler without anthropogenic influence. For the specific record of 38°C at Verkhoyansk, the study found a confident anthropogenic shift in intensity of 1.5°C, although the probability ratio for this specific station event is of lower confidence. By 2050, the regional heat is expected to be further intensified, with a synthesis change in intensity of 4.85°C compared to 1900.

The study assesses the 2018 heatwave in Northern Europe using observational data and climate models to determine the role of human-induced warming. It finds that the probability of such an event has increased across the region, with the most significant increases in probability estimated in Ireland, Denmark, and the Netherlands. While the heat was most extreme in the high Arctic (northern Finland), where it exceeded historical records, the risk ratio was more easily quantified in southern regions. The authors conclude that anthropogenic climate change made these heatwaves more likely, though the exact magnitude of the increase is harder to quantify in Scandinavia due to high natural variability.

The summer of 2017 saw extreme heat across Southern Europe, including the 'Lucifer' heat wave in early August. World Weather Attribution analysis indicates that human-induced climate change significantly increased the likelihood of these events. A summer as hot as 2017 is now estimated to have a 1 in 10 annual chance in the Euro-Mediterranean region and is projected to become normal weather by the middle of the century under continued greenhouse gas emissions.

The study finds that the July 2019 heatwave in Western Europe was made significantly more likely and intense by human-induced climate change. In France and the Netherlands, the event would have been extremely improbable without human influence, with return periods exceeding 1,000 years. Across all analyzed locations, the heatwave was 1.5 to 3 °C hotter than it would have been in an unchanged climate. The analysis utilized a combination of observational data and eight climate model ensembles, noting that while models generally underestimate temperature trends and overestimate variability, they still simulate large probability changes.