Abstract/Summary

Tropical cyclones (TCs, aka hurricanes and typhoons) generally form at low latitudes with access to the warm waters of the tropical oceans but far enough off the equator to allow planetary rotation to cause aggregating convection to spin up into coherent vortices. Yet, current prognostic frameworks for TC latitudes make contradictory predictions for climate change. Simulations of past warm climates, such as the Eocene and Pliocene, show TCs forming and intensifying at higher latitudes than preindustrial conditions. Observations and model projections for the twenty-first century indicate TCs may again migrate poleward in response to anthropogenic greenhouse gas emissions, posing profound risks to the planet‟s most populous regions. Previous studies largely neglected the complex processes occurring at temporal and spatial scales of individual storms since these are poorly resolved in numerical models. Here we review this mesoscale physics in the context of the responses to climate warming of the Hadley circulation, jet streams and Intertropical Convergence Zone (ITCZ). We conclude that twenty-first century TCs will likely occupy a broader range of latitudes than over the last 3 million years as low latitude genesis will be supplemented with increasing midlatitude TC favourability, although precise estimates for future migration remain beyond current methodologies.