A record-breaking drought may have helped push Syria into all-out civil war, according to research.

Parts of the country were ravaged by the worst ever dry spell to hit the region between 2006 and 2010 and this may have been a factor in propelling the 2011 uprising, scientists said.

Agriculture was destroyed, driving dispossessed farmers to cities where poverty, government mismanagement and other factors caused unrest that exploded into full-scale conflict in 2011, the study found.

“We’re not saying the drought caused the war,” said Richard Seager, a climate expert at Columbia University’s Lamont-Doherty Earth Observatory, who co-authored the study.

“We’re saying that added to all the other stressors, it helped kick things over the threshold into open conflict. And a drought of that severity was made much more likely by the ongoing human-driven drying of that region.”

It is the first scientific paper to make the case that human-caused climate change is already altering the risk of large-scale social unrest and violence

The study, published in the leading journal Proceedings of the National Academy of Sciences, said the drought’s effects were immediate.

Agricultural production plunged by a third, cereal prices doubled and nutrition-related diseases among children soared. Up to 1.5 million people fled the countryside to the outskirts of cities already under strain from influxes of refugees from neighbouring Iraq. Study co-author Shahrzad Mohtadi said that the ruling Assad regime did little to help people with employment or services, researchers said, and it was largely in these areas where the uprising began.

“Rapid demographic change encourages instability,” the research paper said.

“Whether it was a primary or substantial factor is impossible to know, but drought can lead to devastating consequences when coupled with pre-existing acute vulnerability.”

The research said it is likely that the drought was stoked by climate change.

Solomon Hsiang, of the University of California, Berkeley, said the study is “the first scientific paper to make the case that human-caused climate change is already altering the risk of large-scale social unrest and violence”.

Marshall Burke, an environmental scientist at Stanford University, said: “There were many things going on in the region and world at that time, such as high global food prices and the beginning of the Arab Spring, that could have also increased the likelihood of civil conflict.”

However, he said the study is “consistent with a large body of statistical evidence linking changes in climate to conflict.”