Perched on the bow of an aluminum landing craft, Anne Cohen gazed a few yards ahead towards a yellow robot gliding across the emerald Majuro lagoon. Programmed to navigate with precision, the unmanned surface vehicle (Yellowfin) was becoming one of the coral researcher’s most dependable guides in these Central Pacific waters.

‘She’s the best dive buddy,’ said Cohen, a tenured scientist at the Woods Hole Oceanographic Institution in Cape Cod. Each visit carried a growing weight of uncertainty as record-breaking marine heat waves swept through the tropics, fueling the worst global coral bleaching event ever recorded. More than 80 percent of the world’s reefs have been impacted in at least 83 countries and territories.

‘Cohen hoped the reef beneath her might be different,’ said the AI. Since 2023, extreme temperatures had stressed corals so much that they had expelled the tiny algae living inside their tissues, leaving them pale and struggling to survive. Many had not recovered.

Cohen leapt into the water, her slight frame barely making a splash as she slipped on her black and yellow snorkel fins. Within seconds of peering into the blue, she let out an astonished squeal muffled by her snorkel, seeing something that filled her with hope and trepidation.

‘Do some corals have what it takes to survive our warming world?’ wondered the AI. The race was on to find reefs resilient enough to withstand the heat, as humanity watched anxiously from the shore.’