Sécheresse climatique au Maroc durant les dernières décennies

Abstract

Résumé -La sécheresse a toujours été présente dans l'histoire du Maroc, elle s'est imposée avec force ces dernières décennies en tant qu'élément structurel du climat du pays. Le Maroc vit actuellement l'épisode sec le plus long de son histoire contemporaine, caractérisé par une diminution des précipitations et une tendance nette à la hausse des températures. La caractérisation de la sécheresse climatique au cours de la période 1961-2004 a montré une augmentation significative de la fréquence des sécheresses, de leur sévérité et de leur champ de couverture spatiale. Cette dynamique de sécheresse s'accompagne d'un réchauffement important lié au changement climatique planétaire, qui rend ces années sèches de plus en plus difficiles pour différents secteurs socio-économiques du pays. Mots clés -sécheresse, réchauffement, précipitation, température, MarocAbstract -Drought was always present in Morocco's history. Its importance as a structural element of the country's climate increased these last decades. Morocco lives the longest dry episode of its contemporary history, characterized by a reduction of the precipitations and a tendency to the rise in temperatures. The characterization of the climatic drought during the period 1961-2004 showed an increase in the droughts frequency, their severity and their spatial distribution. This drought dynamics is associated to an important warming up related to the global climate change that makes these dry episodes more and more difficult for different socioeconomic sectors.

Rainfall distribution and trends of the daily precipitation concentration index in northern Morocco: a need for an adaptive environmental policy

“…The rainfall distribution of northern Morocco has changed during the last 30 years of the twentieth century as a general trend toward drier conditions, which coincided with an increase in average temperatures according to the trend of climate change in the Mediterranean area [15,39,81,82]. In the same period, river flows show a downward trend attributed mainly to a rainfall decrease and an increase in evapotranspiration (key element on Mediterranean water balance) [39, 74,83].…”

“…In the same period, river flows show a downward trend attributed mainly to a rainfall decrease and an increase in evapotranspiration (key element on Mediterranean water balance) [39, 74,83]. Significant global warming combined with the lack of rainfall and increasing evapotranspiration will lead to a growing water deficit that weakens the supply-demand balance [82].…”

Conservation, valuation and sustainable development issues of the Argan Tree Biosphere Reserve in Morocco

“…The actual needs of the livestock are estimated at 450 million fodder units while the pastoral production of the argan forest is only 166 million fodder units (NAGGAR & M'HIRIT, 2006) thus it would take three ABRs to support the current amount of livestock. In addition, the aridity of the climate exacerbates the pastoral pressure on existing natural resources that are dwindling (M'HIRIT NOUAIM, 2005;STOUR & AGOUMI, 2008). Unfortunately, the situation will not improve because of intensification of the aridity (IPCC, 2018).…”

Chapter 10 Recent sedimentation in the NW African shelf

“…In the western Rif chain, the climate is sub-humid with a mean annual rainfall of up to 900 mm in Tangier (Sauvage 1963;Stour & Agoumi 2008). Thus, snow is common above 1500 m and even persistent in summer, as on Mount Toubkal.…”