AGU: Geophysical Research Letters

 

Editors' Highlight

Long-term drought severity variations in Morocco

Since the 1980s, northwestern Africa has experienced drought conditions, resulting in socioecological consequences including reductions in agricultural productivity and drinking water supplies. Though largely related to precipitation changes, the persistence of this drought also seems to be forced by regional surface warming. Noting that long-term high-resolution records of climate are missing for North Africa, Esper et al. (2007) studied tree ring data collected from Atlas cedars in Morocco. Through reanalysis of tree ring data collected in the 1980s, combined with surveys of old growth collected in 2002, the authors identified drought occurrences back to A.D. 1049. They found that relatively wet conditions persisted for most of the period between 1450 and 1980, making the recent drought seem exceptional. The wet period was preceded by drier conditions spanning back to 1049. The pattern of dry to wet to recent dry conditions is similar to trends seen in records from North America. The authors suggested that this similarity might indicate global connections, possibly related to changes in solar irradiance or large-scale weather patterns such as El Niño.

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