Here, using the Berkeley Earth temperature dataset and key heatwave metrics, the authors systematically examine regional and global observed heatwave trends. In almost all regions, heatwave frequency demonstrates the most rapid and significant change. A measure of cumulative heat shows significant increases almost everywhere since the 1950s, mainly driven by heatwave days. Trends in heatwave frequency, duration and cumulative heat have accelerated since the 1950s, and due to the high influence of variability, this paper recommend regional trends are assessed over multiple decades.
The results of this study have important implications for all systems affected by chronic heat exposure. This is because of the appropriate management and adaptation of these systems is influenced by the separate components that drive the overall change. For example, longer, slightly warmer heatwaves may require different management strategies across various sectors such as public health, and energy supply than shorter and more intense events despite a similar change in cumulative intensity.