The Arctic Ocean has been warming dramatically since 2010, especially in summer, with some regions heating up by 2.5°C per decade. This rapid warming is caused by different processes in different areas - some regions warm due to increased moisture in the air, while others warm because of reduced cloud cover.
This Arctic warming affects weather patterns across Europe by weakening the temperature differences between the Arctic and mid-latitudes. When these temperature differences weaken, it reduces the strength of atmospheric waves that normally move weather systems along. As a result, weather patterns become more persistent and 'stuck,' leading to longer-lasting heatwaves in Europe. Since 2010, European heatwaves have become notably more persistent, with some lasting over 60 days compared to typical durations of 10-15 days in earlier decades. This research helps explain why Europe has been experiencing more prolonged extreme heat events in recent years.