Heatwaves: Changes in frequency and intensity

I’ve found myself thinking a lot about this paper by Herold et al. over the past few days. It describes the far-reaching implications of climate change for health and agriculture across different regions within Australia.

In particular I keep thinking about the implications of these two graphs:

The first graph shows heatwave frequency and the second one shows heatwave amplitude for different Australian cities for the recent past (blue), near-future (green) and far-future (red). Bottom and top of boxes indicate the 25th and 75th percentiles.

NB: For those not familiar with it, heatwave amplitude is a way of measuring and modelling the hottest day of the hottest heatwave within a year. This is different from the other common way of measuring heatwave intensity– magnitude–that looks at the average temperature across all heatwave days within a year. °C2 is a heatwave unit of measurement and isn’t the same thing as degrees Celsius.

There are many impacts and consequences associated with this model, but the frequency and scale of near- and far-future heatwaves alone should terrify us.

Source: Herold, N., M. Ekström, J. Kala, J. Goldie, and J. P. Evans. 2018. “Australian Climate Extremes in the 21st Century According to a Regional Climate Model Ensemble: Implications for Health and Agriculture.” Weather and Climate Extremes 20:54–68.