Changes in regional heatwave characteristics as a function of increasing global temperature

Abstract

The Paris Agreement calls for global warming to be limited to 1.5–2 °C. For the first time, this study investigates how different regional heatwave characteristics (intensity, frequency and duration) are projected to change relative to increasing global warming thresholds. Increases in heatwave days between 4–34 extra days per season are projected per °C of global warming. Some tropical regions could experience up to 120 extra heatwave days/season if 5 °C is reached. Increases in heatwave intensity are generally 0.5–1.5 °C above a given global warming threshold, however are higher over the Mediterranean and Central Asian regions. Between warming thresholds of 1.5 °C and 2.5 °C, the return intervals of intense heatwaves reduce by 2–3 fold. Heatwave duration is projected to increase by 2–10 days/°C, with larger changes over lower latitudes. Analysis of two climate model ensembles indicate that variation in the rate of heatwave changes is dependent on physical differences between different climate models, however internal climate variability bears considerable influence on the expected range of regional heatwave changes per warming threshold. The results of this study reiterate the potential for disastrous consequences associated with regional heatwaves if global mean warming is not limited to 2 degrees.

Detectable Impacts of the Past Half‐Degree Global Warming on Summertime Hot Extremes in China

“…Responsive changes of severest events, as represented by the heat stress index, may differ obviously from those of quantile‐based single‐day events (Diffenbaugh et al, ; Li et al, ; Perkins‐Kirkpatrick & Gibson, ). As shown in Figure a, the 0.5°C global warming has aggravated complex event‐produced heat stresses to the extent far beyond the range of internal variability.…”

Projected Heat Stress Under 1.5 °C and 2 °C Global Warming Scenarios Creates Unprecedented Discomfort for Humans in West Africa

“…Therefore, in line with the Paris Agreement, the scientific community is increasingly interested in investigating the climate change impacts associated with the 0.5°C difference between the two warming targets (i.e., 1.5°C and 2°C; James & Washington, 2013;Perkins-Kirkpatrick & Gibson, 2017;Schleussner et al, 2016). Despite the prominence of these two targets, only few studies have attempted to quantity the corresponding regional climate impacts over Africa.…”

Warming Trends in Summer Heatwaves

“…There is increasing evidence that global warming is leading to more intense and frequent heatwaves with a corresponding increase in their impact (Liss et al, 2017;Mora et al, 2017;Pachauri & Meyer, 2014). Direct statistical quantification solely from observations of how heatwaves may be changing in time is thus highly uncertain, although comparable analysis of model output can be less uncertain due to the ability to generate multiple ensembles (Perkins-Kirkpatrick & Gibson, 2017). They are multiday runs of daily observations at unusually high temperatures that are found in the tail of the distribution.…”