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Hadley Cell Expansion

As global temperatures rise, the temperature difference between the poles and the equator is likely to decrease, expanding the cell of air circulation adjacent to the equator known as the Hadley cell. One effect this has is that mid-latitude regions like the Mediterranean and the Southwestern US are likely to see an increase in sea level pressure—which corresponds to drier weather.

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Climate science at a glance

  • Hadley cell expansion is one of the most well-established atmospheric responses to global warming.
  • The Hadley cell has expanded toward the poles since the 1980s.[1]
  • Human emissions have contributed to Hadley cell widening, especially in the Southern Hemisphere.
  • Hadley cell expansion leads to crop lands in the subtropics experiencing drier climate conditions.


What is the Hadley cell?

The Hadley cell, or Hadley circulation, is a worldwide tropical atmospheric circulation pattern that transports energy from the tropics to the subtropics (usually between the 20 and 40° latitude lines in both hemispheres ). The cell develops in response to intense solar heating near the equator.[2] Warm air near the equator rises and flows toward the poles and then cools off, descending, and flowing back toward the equator.

The Hadley cell controls precipitation in the subtropics and it creates a region called the intertropical convergence zone (ITCZ), which produces a band of intense and wet storms.

Why do we care about Hadley cell expansion?

Hadley cells have a major effect on weather patterns in subtropical regions, including portions of the southern United States. The key concern is that widening of the Hadley circulation would cause a poleward shift of the subtropical dry zone (which is located where air in the Hadley cell descends). This could lead to regional rainfall reductions and the drying of subtropical landmasses, which has major implications for crop productivity. Regions that face impacts in the Northern Hemisphere include southern Europe, the Mediterranean region and northern Africa. In the Southern Hemisphere, at risk regions including South Africa, central Chile, and southern and southwestern Australia.

Hadley cell expansion trends and climate change

Studies attribute Hadley cell expansion to climate change 

Select a pillar to filter signals

Air Mass Temperature Increase
Arctic Amplification
Extreme Heat and Heat Waves
Glacier and Ice Sheet Melt
Global Warming
Greenhouse Gas Emissions
Land Ice and Snow Cover Decline
Land Surface Temperature Increase
Permafrost Thaw
Precipitation Falls as Rain Instead of Snow
Sea Ice Decline
Sea Surface Temperature Increase
Season Creep/ Phenology Change
Snowpack Decline
Snowpack Melting Earlier and/or Faster
Atmospheric Moisture Increase
Extreme Precipitation Increase
Runoff and Flood Risk Increase
Total Precipitation Increase
Atmospheric Blocking Increase
Atmospheric River Change
Extreme El Niño Frequency Increase
Gulf Stream System Weakening
Hadley Cell Expansion
Large Scale Global Circulation Change/ Dynamical Changes
North Atlantic Surface Temperature Decrease
Ocean Acidification Increase
Southwestern US Precipitation Decrease
Surface Ozone Change
Surface Wind Speed Change
Drought Risk Increase
Land Surface Drying Increase
Intense Atlantic Hurricane Frequency Increase
Intense Cyclone, Hurricane, Typhoon Frequency Increase
Intense Northwest Pacific Typhoon Frequency Increase
Tropical Cyclone Steering Change
Wildfire Risk Increase
Coastal Flooding Increase
Sea Level Rise
Air Mass Temperature Increase
Storm Surge Increase
Thermal Expansion of the Ocean
Winter Storm Risk Increase
Coral Bleaching Increase
Habitat Shift or Decline
Parasite, Bacteria and Virus Population Increase
Pine Beetle Outbreaks
Heat-Related Illness Increase
Infectious Gastrointestinal Disease Risk Increase
Respiratory Disease Risk Increase
Vector-Borne Disease Risk Increase
Storm Intensity Increase
Tornado Risk Increase
Wind Damage Risk Increase
What are Climate Signals?