Summary/Abstract
From boreal winter 2020 onwards, a large region in West Asia encompassing Iran, Iraq, and Syria suffered from exceptionally low rains that have been reported to be up to 95% below average (Al-Monitor, 2023). The resulting 3-year drought has led to severe impacts on agriculture, in a region where a large part of the population depends on wheat farming and livestock.
In this event study, the authors used three different observations-based data products to assess a trend towards more severe droughts in both regions. The authors find that the combination of low rainfall and high evapotranspiration as unusual as the recent conditions – that is, an event that occurred around every 5-10 years – would be so much less severe that it would not be classified as a drought at all in a world that had not been warmed 1.2°C.
In order to identify whether and to what extent human-induced climate change was a driver of these trends, the authors combine observations-based data products and climate models and look at the 36-month Standardised Precipitation Evapotranspiration Index in both regions. The study finds that over the Euphrates-Tigris basin the likelihood of such a drought occurring has increased by a factor of 25 compared to a 1.2°C cooler world. Over Iran the likelihood of such a drought occurring has increased by a factor of 16 compared to a 1.2°C cooler world.