More perceived but not faster evolution of heat stress than temperature extremes in the future
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More perceived but not faster evolution of heat stress than temperature extremes in the future Audrey Brouillet1
· Sylvie Joussaume1
Received: 5 January 2020 / Accepted: 20 May 2020 / © The Author(s) 2020
Abstract Global warming is projected to intensify during the twenty-first century. Yet, only few studies investigate how global warming could be perceived by future populations. Here, we propose an assessment of how climate change could be perceived by combining climatological indicators. We analyse extremes of temperature (T99 ) and simplified Wet-Bulb Globe Temperature (WBGT99 ), a heat stress index assessing the combined effect of elevated temperature and humidity on the human body. The speed of change is defined for each year as the difference between the previous 20 years and the twenty upcoming years (i.e. with a moving baseline), and we assess how these speeds emerge from each last 20year interannual variability. Using a set of 12 CMIP5 models, speeds of change of T99 and WBGT99 in 2080 are both twice as fast compared with current speeds in mid-latitudes, and by up to four times faster in the tropics under the RCP8.5 scenario. Warming accelerations are thus similar for T99 and WBGT99 . However, these speeds in tropical regions in 2080 are projected to be 2.3 times larger than the last 20-year interannual variability for WBGT99 , and only 1.5 to 1.8 times larger for T99 . According to the models, the WBGT99 intensification will be more emergent from the recent year-to-year variability than the T99 warming. This analysis suggests that the accelerated warming of heat extremes will be felt more strongly by populations than current changes for RCP8.5, and that this evolution will be more perceived in heat stress than in temperature, particularly within the tropics. Keywords Extremes · Heat stress · Temperature · Speed of change · Global warming · Climate models
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10584-020-02752-z) contains supplementary material, which is available to authorized users. Audrey Brouillet
[email protected] 1
Laboratoire des Sciences du Climat et de l’Environnement (LSCE-IPSL), CEA/CNRS/UVSQ, 91191, Gif-sur-Yvette, France
Climatic Change
1 Introduction A recent and unprecedented warming of the atmosphere and oceans has been exhibited in many studies (Hartmann et al. 2013). This global warming mainly results from the increased levels of greenhouse gases induced by anthropogenic activities. General circulation models (GCMs) project a continuous warming during the twenty-first century under the high baseline emission RCP8.5 scenario, and a “peak-and-decline” warming with the mitigation RCP2.6 pathway (van Vuuren et al. 2011). Models simulate a larger future mean warming over land than over oceans (Collins et al. 2013). According to GCMs, this mean change and a preferential warming of the hot tail of temperature distributions both lead to an increase in amplitude, frequency and duration of warm extremes over land (e.g. Me
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