Storms track further poleward under climate change

In a warming climate, mid-latitude storms will travel further towards the poles before they reach their maximum intensity, with potentially severe implications for mid-latitude weather, reports a paper published online this week in Nature Geoscience. The study suggests that impacts on local weather and climate are likely to be strongest in regions that are close to the northeastern ocean boundaries, such as the United States west coast and Britain.

Low-pressure storms outside the tropics are often associated with intense precipitation and wind. Based on climate model simulations, their tracks are expected to shift poleward in a changing climate, but the dominant underlying mechanisms are debated.

Talia Tamarin-Brodsky and Yohai Kaspi analysed simulations from 20 state-of-the-art climate models with an algorithm that allowed them to identify the tracks of individual storms. They found that a significant part of the poleward shift of storm activity can be attributed to a longer propagation distance, which they suggest is caused by stronger winds at the upper level of the atmosphere and increased concentrations of atmospheric water vapour.