What if Islamic State militants are not beaten back but continue to extend their brutal writ across Iraq and Syria? What if the Taliban continue to increase their territorial gains in Afghanistan, prompting even more people to flee? A quarter of Afghans told a Gallup Poll that they want to leave, and more than 100,000 are expected to try to flee to Europe this year.

There are between six million and eight million people displaced in Syria, along with more than four million Syrian refugees in Lebanon, Turkey and Jordan.

Egypt’s five million or more Copts, the Middle East’s last remaining major Christian sect, are deeply worried about their future in an unstable and hostile country. Ancient minority groups like the Yazidis of Iraq are already homeless, as are many small communities of Assyrian, Nestorian and Chaldean Christians from northern Iraq.

While Yemenis have yet to abandon their homeland in substantial numbers, their plight is worsening daily amid wartime shortages of food and medicine and persistent bombardment by Saudi warplanes. Yemen is not much farther away from Europe than Eritrea, now the biggest source of African refugees, just across the Red Sea, and at some 25 million it is as populous as Afghanistan.