Floods and Droughts: the Medieval Climatic Anomaly

On 19 February 974 (363 ah), after many days of heavy rain, the River Guadalquivir burst its banks and flooded Córdoba's riverside market, with the floodwater rising above the butchers’ counters. A few weeks later, at the start of April, another rise in the river's level once more inundated these shops. Neither of these episodes resulted in any victims, but a few decades later, in 1010 (401 ah), another flooding of the Guadalquivir is said to have caused hundreds of deaths. When in spate, the river could wreak destruction, as it could rise seven and as much as ten metres above its normal level. Even today, and despite the Guadalquivir being carefully controlled by reservoirs and dams, the city of Córdoba floods when the river's discharge rises above 1,500 cubic metres per second; when it reaches 5,400 cubic metres it causes disaster, as occurred in 1963. Obviously, during the Umayyad caliphate much lower volumes could quite conceivably cause major catastrophes.

Floods, just like droughts, had a considerable impact on the natural order of things in the caliphate of Córdoba: harvests, tax collecting, military campaigns and trading activity were all affected by torrential rain and oppressive droughts. As a result, at the court of al-Ḥakam II the climate, far from being considered a trivial matter, was subject to meticulous study: the weather was recorded on a regular basis, its effects on the harvests were carefully assessed, and, when conditions became severe and struck the people with unexplainable force, the caliph and the religious Muslim leaders prayed to God beseeching him to alleviate the suffering these disasters were causing. Thereby, to counter the unforeseeable nature of the elements, a powerful courtly narrative was fashioned of the Umayyad caliphate as encompassing a predictive capacity that sought to mitigate the consequences of the trials God unleashed on the peoples of al-Andalus.

From the second half of the ninth century (third ah) these trials tended to become more frequent, as extreme climatic conditions increased. This was caused by the beginning of what has been termed the ‘Medieval Climatic Anomaly’, which caused temperatures and rainfall in the Western hemisphere to undergo significant changes.