(New Scientist) What goes around comes around. The first global comparison of coastal sediments has identified long-term cyclical variations in severe tropical cyclone activity. The cycles, too long to be detected in historical records, suggest some areas considered safe from cyclones have experienced intense storms in the past and may eventually feel their force again.
We know from historical records that the numbers of tropical storms in the North Atlantic and Pacific rise and fall over multi-decadal cycles, but those data only span 100 to 150 years. For evidence of longer-term cycles, researchers must turn to the geological record, where ancient storms can be detected by the destruction they caused – washing sand into lagoons and leaving a series of ridges along low-lying coasts.