Planting trees in the sea could act as a huge carbon sink and save millions of dollars in storm damage every year. What is stopping us from doing it?

A series of trees stand in the middle of a drowned swampland, with still water reflecting the purple and orange dusky sky and a few patches of grass poking above the water here and there.

Planting trees along coastlines with human-made shore defenses, such as dikes, could protect more than 140,000 people from flooding and save up to $800 million from flood damage globally each year, a new study finds.

Places that have mangroves, such as parts of Florida, are better able to withstand the ravages of storms and their powerful waves. But although there is a push to restore mangroves around the world, there are several challenges.