Global Decadal Hydroclimate Predictability, Variability and Change: A Data-Enriched Modeling Study (GloDecH)
Lamont-Doherty Earth Observatory of Columbia University 61 Route 9W Palisades, NY 10964

Climate change in the Fertile Crescent and implications of the recent Syrian drought

Colin P. Kelley, Shahrzad Mohtadi, Mark A. Cane, Richard Seager and Yochanan Kushnir

Photo taken by Reuters

While working on hydroclimate change in the Mediterranean region, there was considerable reporting from North Africa and the Middle East about how strained water resources were causing social problems. In collaboration with Shahrzad Mohtadi, we therefore decided to conduct a study of hydroclimate change and drought in Syria. This was motivated by reporting that an extended drought that began in 2006, against a background of declining groundwater and changes in agricultural and subsidy policies, had led to abandonment of farming regions within Syria and migration to cities and that in turn was leading to social unrest within the cities. Syria was already under stress at the time because of the influx of about 1.5 million refugees fleeing the war in neighboring Iraq. In the resulting paper we argued that the combined impact of Iraqi refugees and internal migration of Syrians from the drought stricken farming communities, in combination a Syrian government response that failed to ameliorate the situation, contributed to the social unrest that eventually led to uprising and cicil war. The paper also finds that a drought of the severity and length that led to the crisis was made two to three times more likely by the greenhouse gas-driven drying and warming of the Middle East. Hence there is a climate change link to the onset of the Syrian war. However it should be noted that the drought and climate change is but one contributor to the war, and possibly not even the prime cause. But that climate played a role in how the war began seems clear. This message has been correctly communicated by amongst others, President Obama, Secretary of State John Kerry, Prince Charles and UK cultural celebrity Charlotte Church.
Here is the abstract of the paper:

Before the Syrian uprising that began in 2011, the greater Fertile Crescent experienced the most severe drought in the instrumental record. For Syria, a country marked by poor governance and unsustainable agricultural and environmental policies, the drought had a catalytic effect, contributing to political unrest. We show that the recent decrease in Syrian precipitation is a combination of natural variability and a long-term drying trend, and the unusual severity of the observed drought is here shown to be highly unlikely without this trend. Precipitation changes in Syria are linked to rising mean sea-level pressure in the Eastern Mediterranean, which also shows a long-term trend. There has been also a long-term warming trend in the Eastern Mediterranean, adding to the drawdown of soil moisture. No natural cause is apparent for these trends, whereas the observed drying and warming are consistent with model studies of the response to increases in greenhouse gases. Furthermore, model studies show an increasingly drier and hotter future mea climate for the Eastern Mediterranean. Analyses of observations and model simulations indicate that a drought of the severity and duration of the recent Syrian drought, which is implicated in the current conflict, has become more than twice as likely as a consequence of human interference in the climate system.

We also wrote a Commentary article explaining our results that was published by Fortune Magazine in December 2015. Here it is:

FORTUNE Magazine, Saturday, December 5, 2015:

Why Prince Charles is Right to Link the Syrian War to Climate Change