A small group of Indigenous women in northern Guyana are the latest weapon in the fight against climate change in this South American country where 90% of the population lives below sea level. Armed with drones, the women are scanning mangrove forests for illegal cutting and expect to soon start collecting soil samples and mangrove litter to measure the carbon held in remote coastal ecosystems that have long been out of reach for scientists. Such data could nudge the government to create policies and programs to protect critical areas. “We are merging traditional knowledge and scientific research to get all this information that we need but never had before and couldn’t afford to get,” said Annette Arjoon-Martins, head of Guyana’s Marine Conservation Society. The women’s work is considered key for Guyana, a small nation about the size of Britain that has a 285-mile-long (459 kilometers) coastline whose coastal plains lie an average of 6 feet (2 meters) below sea level. The coastline depends on a centuries-old sea defense system created by the Dutch during the colonial era. It includes a 280-mile (450-kilometer) seawall and relies on dozens of workers who set alarms night and day to manually open and close sluice gates known as “kokers” that prevent the Atlantic Ocean from flooding Guyana. By the mid-1990s, the Inter-American Development Bank already was advising Guyana to relocate communities inland since most of its 791,000 people live along the coast, and much of its economic activity and agriculture are based there. But people have been reluctant to leave.