It’s a lost paradise. Lake Chad, once the life spring of the Sahel region touching Chad, Cameroon, Nigeria and Niger, has been anything but since the 1970s. Drought and disease came as colonial borders split communities and authoritarian leaders rose to power. Then came Boko Haram in 2015, stoking war that’s scorched the diminishing lake’s islands, creating the world’s most complex humanitarian disaster. As foreign powers pour aid and military support into the region, some desperate Chadians are moving toward the Nigerian conflict — where refugee centers offer their only hope of nourishment.