High‐Temperature Extreme Events Over Africa Under 1.5 and 2 °C of Global Warming

Abstract

With anthropogenic global warming, heat‐related extreme events are projected to increase in severity and frequency. Already vulnerable regions like Africa will be hard‐hit. Therefore, such regions could benefit from low global warming levels. Using the Community Earth System Model low warming simulations, we investigate changes in temperature extremes across Africa as a function of global mean temperature in the context of the implications of the Paris Agreement's targets. A significant warming across Africa is projected at the 1.5 °C warming world and is amplified at the 2 °C world, exceeding the mean global warming rate. Specifically, North Africa and East Africa regions are projected to have the highest and lowest temperature changes of 0.63 °C (0.60–0.67 °C) and 0.50 °C (0.47–0.54 °C), respectively, between the 1.5 and 2 °C warmer worlds. Consequently, hot events are also estimated to increase with global warming. We showed that limiting warming to 1.5 °C instead of 2 °C may lead to 29% (27–31%) to 35% (33–37%) reduction in severity of hot events and to 31% (30–33%) to 42% (39–48%) reduction in the frequency of the threshold‐based high‐temperature events across Africa. The highest reductions are projected over North Africa. Furthermore, restricting warming to 0.5 °C lower than 2 °C might also result in 28% (34–40%) to 37% (25–34%) reduction in severity of once‐in‐10/20‐year heat events across Africa with North Africa having the highest benefits than tropical regions. Thus, restricting warming to low levels may indeed translate to substantial benefits of reduced intensity and frequency of extreme heat events across Africa.

Characteristics and thermodynamics of Sahelian heatwaves analysed using various thermal indices

“…Yet like other regions there are clear upward trends in Sahel temperatures (e.g., Guichard 2014;Moron et al 2016) most notably during nighttime. Recent studies showed upward trends in duration, frequency and intensity of heatwave events over the past decades (Fontaine et al 2013;Moron et al 2016;Ceccherini et al 2017;Barbier et al 2017) and future projections also show a growing risk of extreme heat in the region (e.g., Nangombe et al 2019;Rohat et al 2019). However, some contradictory evidence of unchanged frequency exists (Adeniyi and Oyekola 2017), which may be related to the choice of heatwave index.…”

How a typical West African day in the future-climate compares with current-climate conditions in a convection-permitting and parameterised convection climate model

“…Global and regionally downscaled climate models project near-surface temperatures to increase by around 3-6°C by the end of the twenty-first century (Patricola and Cook 2010;Fontaine et al 2011;Mariotti et al 2011;Diallo et al 2012;Vizy et al 2013;Riede et al 2016). Further, extreme hot days (> 90th percentile of present climate) are expected to be more frequent (Russo et al 2014;Dosio 2017;Weber et al 2018;Nangombe et al 2019;Yapo et al 2019).…”

Extreme hot days over three global mega‐regions: Historical fidelity and future projection

“…The Paris Agreement set a preferable target to limit global warming to 1.5 C above preindustrial levels (United Nations Framework Convention on Climate Change, 1992), and many studies have projected extreme events in models for this 1.5 C warming level (Li et al, 2019;Zhao and Zhou, 2019). Thus, for the comparison with the historical epoch , the period of 2030-2054 was chosen as the future epoch for the following analysis, during which global warming is likely to reach the 1.5 C level (IPCC SR15, 2018;Nangombe et al, 2019). Figure 4 shows the trend ratios for the three regions and the three indicators under the RCP4.5 and RCP8.5 scenarios.…”