Mark Lynas famously makes much of his living advising the government of the Maldives on climate change. The chief alleged threat to these low-lying atolls is of course that they are going to be swamped by rising seas.
Unfortunately for Lynas, a news article (£) in Science magazine suggests that his position is based on a misconception about how atolls work.
In 1999, the World Bank asked [University of Auckland geomorphologist Paul Kench] to evaluate the economic costs of sea-level rise and climate change to Pacific island nations. Kench, who had been studying how atoll islands evolve over time, says he had assumed that a rising ocean would engulf the islands, which consist of sand perched on reefs. “That’s what everyone thought, and nobody questioned it,” he says. But when he scoured the literature, he could not find a single study to support that scenario. So Kench teamed up with Peter Cowell, a geomorphologist at the University of Sydney in Australia, to model what might happen. They found that during episodes of high seas—at high tide during El Niño events, which raise sea level in the Central Pacific, for example—storm waves would wash over higher and higher sections of atoll islands. But instead of eroding land, the waves would raise island elevation by depositing sand produced from broken coral, coralline algae, mollusks, and foraminifera. Kench notes that reefs can grow 10 to 15 mill imeters a year—faster than the sea-level rise expected to occur later this century. “As long as the reef is healthy and generates an abundant supply of sand, there’s no reason a reef island can’t grow and keep up,” he argues.
This isn't new of course. Kench's work is years old and was mentioned in de Lange and Carter's report on sea-level rise for GWPF. But it's interesting to see Sciencemag allowing such heresy on its pages.