The alert came in the middle of the afternoon. Somewhere in the flooded forest of Cambodia, a fire had started.

Luon Chanleng and fellow members of the Ou Taprok community patrol team didn’t wait. When a fire takes hold during the dry season, the difference between a contained blaze and a catastrophe is measured in minutes.

“The flooded forest is the nursery for fish and home of biodiversity,” he said. “When the forests are healthy, fish can breed and grow. But if the forest burns, the fish dwindle — and that affects the livelihoods of our whole community. I can’t imagine our life without the forest.”

Chanleng and his team moved fast, fanning out through the dry undergrowth to cut off the fire before it could spread. They had exact coordinates — dispatched automatically the moment a satellite detected heat in the forest. When they reached the fire, it was still small enough to fight.…