When Hurricane Mitch tore through Honduras in October 1998, it left behind 7,000 dead and a country of ruined homes, floating bodies and broken infrastructure. Evelyn, then a teenager in Tegucigalpa, watched floodwater swallow her family's furniture, doors and windows. Mosquito-borne illness followed. Her relatives in New York City, seeing no future in the wreckage, sent a simple message: bring the children here.

She came. More than two decades later, she has two daughters — one training to be a lawyer, the other a doctor — and a clear-eyed view of how much harder her journey would be today. The legal framework that governs who may enter the United States has never recognised environmental displacement as a valid ground for asylum. International refugee law, drafted in the aftermath of the Second World War, likewise contains no provision for people driven from their homes by floods, storms or extreme heat.

Scientists have established that hurricanes of Mitch's ferocity are becoming more probable as fossil-fuel emissions warm both the atmosphere and the oceans.