The summer of 2024 was the hottest on record and, unfortunately, this came as no surprise. Summers have been getting hotter and drier around the world, including in the Northern Hemisphere, leading to intense droughts and heatwaves in North America and Europe and posing serious risks to society such as wildfires, crop failures and health hazards. Part of the problem is that the Earth’s air circulation systems, which help spread and disperse moisture and heat throughout the world, have been weakening over the years. However, the exact reasons for this weakening have eluded researchers.
Now, in two studies led by Dr. Rei Chemke of the Weizmann Institute of Science, researchers have managed to crack this mystery: Human activity is what has been making the air circulation systems weaker.
In a study conducted with Prof. Dim Coumou of Amsterdam’s Institute for Environmental Studies (Vrije Universiteit Amsterdam), Chemke showed for the first time that the weakening of storm tracks is due to manmade emissions of greenhouse gasses, such as CO2, and aerosols.
“These emissions warm the air more at the high latitudes than at the low latitudes,” says Chemke. As a result, the temperature gap between northern and southern latitudes – which drives these storm tracks in the first place – has become smaller, and this reduction has led to a weakening of the storm tracks.
Want to understand the implications of these findings? Read more here.
