Heatwave in northern Europe, summer 2018

Key findings

• The heat (based on observations and forecast) is very extreme near the Arctic circle, but less extreme further south: return periods are about 10 years in southern Scandinavia and Ireland, five years in the Netherlands
• From past observations and models we find that the probability of such a heatwave to occur has increased everywhere in this region due to anthropogenic climate change, although in Scandinavia this increase was not visible in observations until now due to the very variable summer weather.
• We estimate that the probability to have such a heat or higher is generally more than two times higher today than if human activities had not altered climate.
• Due to the underlying warming trend even record breaking events can be not very extreme but have relatively low return times in the current climate.
• With global mean temperatures continuing to increase heat waves like this will become even less exceptional