The Pentagon got serious about mitigating climate disasters after the 155-mile-per-hour winds of Hurricane Michael left Tyndall Air Force Base “virtually leveled,” as one military spokesperson described the damage. The unsparing Category 5 storm flipped fighter jets and somehow crumpled entire hangars intended to keep aircraft safe from the elements as the hurricane ripped through northwest Florida on October 10, 2018. The military’s Defense Advanced Research Projects Agency (DARPA) called this new plan “ Reefense ”—a program to develop “self-healing, hybrid biological and engineered reef-mimicking structures” to radically reduce any future damage caused by coastal flooding, erosion, and all those increasingly common episodes of extreme weather . And, surprisingly, the program appears to be succeeding far better than anyone could have reasonably expected.…