A decade of German heatwave data reveals shift in local impact perception

Heat is a global public health risk, even in temperate climates like Europe, which has experienced an increasing number of intense heatwaves over the past decade. This study uses a unique dataset of more than 57,000 X (formerly Twitter) conversations from users in Germany about heatwaves between 2013 and 2022. We showed that, as heatwaves in Germany have become more frequent and intense, social media activity on this topic has also increased. Structural topic modelling revealed nine topics, with an increase in the number and diversity of topics since 2018, a year marked by unprecedented drought and heat in Europe, including Germany. Before 2018, German heat-related tweets primarily expressed concerns about global heatwaves and their associated mortality, such as those in Australia. In 2015, there was a brief spike in tweets as users began to comment on the local impacts of heat on their daily lives, including complaints about high temperatures, air-conditioning shortages and heat-related train delays. However, it was in 2018 that conversations about local heat impacts and personal adaptation strategies proliferated. That year initiated a long-term shift in perceptions of heatwaves in people in Germany, including growing concerns about health implications, droughts and wildfires shifting from being a problem outside Europe to one affecting many European countries, including those frequently visited by Germans as tourists.