Persistent Brazil floods raise specter of climate migration

Devastating and ongoing flooding in southern Brazil is forcing some of the half million displaced residents to consider uprooting their lives from inundated towns to rebuild on higher ground.

Two weeks after the onset of torrential rains, the Guaiba River running by state capital Porto Alegre is rising again, having passed the all-time high. In the state of Rio Grande do Sul, the streets of dozens of towns have turned into slow-moving rivers.

With hundreds of thousands of families fleeing the floods, the disaster - which has killed at least 147 people, with 127 still missing - could touch off one of Brazil's biggest cases of climate migration in recent history.