Tropical cyclones (TCs), including hurricanes and typhoons, are a major hazard around the globe, including North America. TCs have exhibited variability and change on a variety of timescales, including multi-decadal changes. Scientists used a novel method to measure changes in TC activity over the past 30 years: the location at which a tropical cyclone achieves its lifetime-maximum intensity (or LMI). Over the past 30 years the typical location of LMI has moved poleward in both hemispheres – at a rate of over 30 miles per decade.