More than 10,000 migrants and refugees traveled to Western Europe via Hungary over the weekend, fleeing conflict-ravaged and impoverished homelands in the hope of finding a more secure life abroad. Even as Europe wrestles over how to absorb the new arrivals, human rights activists and migration experts warn that the movement is not likely to slow anytime soon. Intractable wars, terror and poverty in the Middle East and beyond will continue to drive the surge. One additional factor, say scientists, is likely to make it even worse: climate change.

From 2006 to 2011, large swaths of Syria suffered an extreme drought that, according to climatologists, was exacerbated by climate change. The drought lead to increased poverty and relocation to urban areas, according to a recent report by the Proceedings of the National Academy of Sciences and cited by Scientific American. “That drought, in addition to its mismanagement by the Assad regime, contributed to the displacement of two million in Syria,” says Francesco Femia, of the Washington, D.C.-based Center for Climate and Security. “That internal displacement may have contributed to the social unrest that precipitated the civil war. Which generated the refugee flows into Europe.” And what happened in Syria, he says, is likely to play out elsewhere going forward.