Article

La dynamique des températures et ses risques pour les populations de Djibouti dans le contexte du réchauffement global

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Abstract

La communauté scientifique est de plus en plus consensuelle sur le réchauffement climatique de notre planète, phénomène déjà envisagé en 1896 par le Suédois Svante Arrhénius. Le présent article se penche sur la question de la température dans la station de Djibouti sur les 60 dernières années dans le but d’interroger les effets du réchauffement climatique en zone hyperaride. Pour ce faire, nous nous sommes appuyé sur les températures enregistrées à la station de Djibouti aérodrome de 1961 à 2015 (plus d’un demi-siècle). Ces températures concernent les maximales, les minimales et les moyennes. En théorie, elles représentent plus de 62 000 valeurs de température. L’étude associe aussi les relevés de l’humidité relative de 2005 à 2015. L’étendue de la période d’étude devait permettre de dégager, si possible, des tendances. Pour une station extrêmement chaude et donc ne possédant pas de marge pour les hausses, la température moyenne n’a cessé de glisser vers le haut. Sur la période étudiée, on note un accroissement de près 2 °C passant de 29,7 à 31,5. Les températures maximales et minimales ont connu les mêmes modifications. Mais ce sont plus les températures minimales qui ont plus gagné des degrés, réduisant ainsi l’amplitude thermique. La température ressentie (en tenant compte de l’humidité relative) s’est établie à des valeurs représentant un danger certain surtout de mai à octobre. Les tendances à la hausse des températures et le maintien de fortes chaleurs, pendant la journée, tendent donc à rendre cette station de moins en moins vivable pour les êtres humains.

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