Corals, trees and marine sediments, among others, are directevidence of the climate of the past, but they are not the onlyindicators. A team led by Spanish scientists has interpretedrecords written in Iraq by Arabic historians for the first time andhas made a chronology of climatic events from the year 816 to 1009,when cold waves and snow were normal. The Arabic historians' records chronologically narrate social,political and religious matters, and some of them mention climate.A study led by researchers from the University of Extremadura(Spain) has focused on ancient meteorological notes of the Iraqicity of Baghdad. "We have recovered an interesting chronology of climatic events,such as droughts, floods, rain, frost, heat and cold waves as wellas strong winds during the period between 816-1009 in the areas nowknown as Iraq and Syria" Fernando Dominguez-Castro, lead author andresearcher in the Physics department at the University ofExtremadura, informed SINC. |
This study, which has been published in the Weather journal,highlights a high number of cold waves. "The period between 902 and944 had a high number if we compare them to current weather data.Examples of this are the six snowfalls that occurred in thatperiod, whilst in our era, we only know of one snowfall in Baghdadon 11 January 2008" Dominguez-Castro highlights. More cold days due to volcanic eruptions The research team was especially surprised by the "unexpected"drop in temperatures in July 920. According to the documentsanalysed, the people of Baghdad had to come down from their roofs(where they would usually sleep in the summer) and go inside theirhouses and even use blankets.
The temperatures could have dropped9C compared to the current average for the month of July. "It is difficult to identify the cause of this drop in temperature,but it could be due to a volcanic eruption the year before, as itis common for summer temperatures to drop in these cases" theexpert points out and says that during some of those nights in July920, temperatures did not exceed 18C. There were two significant volcanic eruptions during that period,which could be the cause of the cold waves, "although there is alot of doubt surrounding the dates", the researcher states. One ofthose was the Ceboruco volcano (Mexico), around 930, and the otherwas the Guagua Pichincha (Ecuador), around 910. Nonetheless, "moreevidence is necessary to confirm this hypothesis" the expert warns.
The research shows that during the first half of the tenth century,the cold climatic events in Baghdad were more frequent and moreintense than today. Although in the Iraqi city only two days withtemperatures below 0C were registered between 1954 and 2008, therewere at least six very cold days in a 42 year period in the tenthcentury. According to the researchers, "the Arabic records are very usefulfor reconstructing the climate in eras and places about which weknow very little". Thanks to the synergy of humans and science'robust climate information' has been extracted" they conclude. Baghdad, the centre of the empire In 762, Abu Ja'far Abdallah al-Mansur, the second Abbasid Caliph(the second Islamic dynasty), founded the city of Baghdad andestablished it as the capital of the empire.
The city soon becamethe most prosperous place at the time, and the centre ofinternational trade and agricultural development, which attracted agrowing population. Historians of the era debated reasons as to why the Caliph gave somuch importance to Baghdad. As well as its strategic locationbetween the Tigris and Euphrates rivers, the city had good weatherconditions. "There was plenty of water, the weather was very warmin the summer, very cold in the winter, and moderate in spring andautumn," Al-Ya`qubi described, author of a geographical treatise in891. Dominguez-Castro, Fernando; Vaquero, Jose Manuel; Marin, Manuela;Gallego, Maria Cruz; Garcia-Herrera, Ricardo.
"How useful couldArabic documentary sources be for reconstructing past climate?"Weather 67(3): 76-82 DOI: 10.1002/wea.835 march 2012.
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