The growth in human-induced emission is weakening the wind patterns that drive global weather, researchers sayHuman-induced climate change has weakened the wind patterns that once pushed cold weather and blazing droughts around the globe — leading to more extreme weather events across Europe and Asia, a new scientific study said. The study, which reveals the extensive influence of our actions on the Earth’s atmosphere, is published today in Nature.
Unraveling the Mystery
For years, scientists have been baffled by the weakening of the Earth’s air circulation systems that move warm moist air to higher altitudes and cold dry air down. Two new studies led by Dr. Rei Chemke of the Weizmann Institute of Science have finally cracked it: human activity.
In particular, the researchers examined two key pieces of this atmospheric circulation network–the Hadley circulation and the storm tracks. This circulation, or flow, of air in the atmosphere helps determine weather patterns around the world and storm tracks — both high-pressure and low-pressure weather systems that flow from west to east.
The Hadley circulation has been declining for decades, but its relationship to human emissions previously received little attention. Chemke and his colleagues then showed that the distortion of the storm track is also a direct consequence of greenhouse gas and aerosol emissions by human activities.
The Science Behind the Shift
Human-made emissions were warming the air more at high, latitudes than at low latitudes, the researchers said. Meanwhile, this decreases the tilt in temperatures from north to south of all regions leading storm tracks over latitudes. Consequently, the storms have lost strength and are now able to carry less cold air from the oceans back onto land.
This is important because the accumulation of warm continent-filled air has fueled more frequent examples of extreme heat, dry spells and fires in the North Hemisphere since this layer of air rise polar. This has wide and clearly far-reaching implications — as the researchers note in their paper, published in the journal npj Climate and Atmospheric Science.
Human-induced emissions were examined as well to determine what effect they have on the Hadley circulation. Using climate models and observational data, the scientists determined that natural influences — principally volcanic eruptions and solar variability — traditionally reinforced a strong Hadley circulation, but we are now achieving the reverse through greenhouse gas emissions.
Conclusion
Research carried out by Dr. Rei Chemke and his colleagues sheds new light on the profound effect that human activities have had on Earth’s wind patterns. Through reducing the storm tracks and the Hadley circulation, our emissions are impairing the global climate system, exacerbating weather extremes whose economic burden and risks to society worldwide are significant. The research drives home the point that action is needed now to address climate change if we wish our planet and ourselves to remain healthy.
