Projected Air Temperature Extremes and Maximum Heat Conditions Over the Middle-East-North Africa (MENA) Region

This study analyzes projected heat extremes over the Middle-East–North Africa (MENA) region until the end of the twenty-first century with a number of temperature indices based on absolute values and thresholds to describe hot conditions. We use model projected daily near-surface air (2-m) temperature (Tmax\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_\mathrm{{max}}$$\end{document} and Tmin\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T_\mathrm{{min}}$$\end{document}) to derive the indices for the period 1980–2100. The data were taken from 18 CMIP5 models combining historical (1980–2005) and scenario runs (2006–2100 under RCP2.6, RCP4.5, and RCP8.5 pathways). Results show a domain-wide projected warming for all emission scenarios. Our findings for a business-as-usual pathway indicate excessive warming of more than 8 ∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ $$\end{document}C in the northern part of the domain (south Europe) for the annual warmest day (TXx) and night (TNx). In the hottest parts of the domain record high temperatures reached 50 ∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ $$\end{document}C in the recent past, which could increase to at least 56 ∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ $$\end{document}C by the end of the century, while temperatures over 50 ∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^\circ $$\end{document}C are expected to occur in a large part of the MENA region. A significant increase is projected in the number of hot days (TX >40∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$>40^\circ $$\end{document}C) and nights (TN >30∘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$>30 ^\circ $$\end{document}C) all over the region. For the period of 2071–2100 excessive hot days and nights will become the normal during summer in large parts of the MENA with some locations expected to exceed 180 and 100 days, respectively. Calculations of the corresponding heat index suggest that several areas across the MENA region may reach temperature levels critical for human survival.