Last updated December 4, 2018

Tropical Cyclone Steering Change

Global warming affects large scale weather patterns and the weather systems, such as hurricanes, embedded within. Research has documented several recent changes in hurricane steering such as increased stalling and shifts toward higher latitudes.

Climate science at a glance

  • There has been a substantial increase in virtually every measure of hurricane activity in the Atlantic since the 1970s, including hurricane steering.[1]
  • Tropical cyclones have shifted toward the poles and this shift is likely due to global warming.[2][3]
  • The fingerprint of human-caused climate change has been found in the slowdown, or stalling, of tropical cyclones worldwide.[5]

Background

What is hurricane steering?

Steering winds, also called steering currents, are the dominant large-scale air flows that govern the movement of smaller features within, such as hurricanes.


Global hurricane steering trends and climate change

  • There has been a substantial increase in virtually every measure of hurricane activity in the Atlantic since the 1970s, including hurricane steering.[1] These increases are linked, in part, to higher sea surface temperatures in the region that Atlantic hurricanes form in and move through.
  • Models suggest that storm tracks shift poleward under global warming due to stronger upper-level winds and increased atmospheric water vapor.[2]
  • A 2015 study has tentatively documented a general slowdown of atmospheric summer circulation in the mid-latitudes.[4]

Global studies attribute changes in hurricane steering to climate change

  • (Baldini et al. 2016): Records suggest that the mean track of Cape Verde tropical cyclones shifted gradually north-eastward from the western Caribbean toward the North American east coast over the last 450 years. Since about 1870, these shifts were largely driven by anthropogenic greenhouse gas and sulphate aerosol emissions.[3]
  • (James Kossin 2018) finds that tropical cyclones world wide have increasingly stalled, their forward speed decreasing, over the past 70 years, due to a slowing in steering patterns attributed to global warming.[5]