Extreme heat and humidity in the United States
(Washington) The extreme heat and oppressive humidity currently gripping the eastern half of the United States would have been “virtually impossible” without climate change, according to a new study released Friday, as the country hosts the World Cup and celebrates its 250th anniversary.e birthday.
Published yesterday at
“On the occasion of the 250e anniversary of the United States, our study represents a stark return to reality,” said Theodore Keeping, researcher who co-authored the World Weather Attribution (WWA) study.
“The climate the country is experiencing is fundamentally different from that which existed when the Founding Fathers signed the Declaration of Independence,” he added.
The WWA, which brings together several climate scientists from leading institutions, studied the current heat wave caused by a powerful pressure system in the shape of a “heat dome”. The latter traps hot and humid air, like a lid placed over the center and east of the country, as well as southern Canada.
Although such weather phenomena are common, they are now leading to higher temperatures due to climate change.
Daytime temperatures exceed 38 degrees Celsius, but the feeling is even higher if we take humidity into account.
The study also focuses on the values of the Wet Bulb Globe Temperature (WBGT) – wet bulb in French, an index which takes into account heat and humidity – which could break records during this extreme heat wave.
Using models, the WWA compared the current world, victim of global warming, to a world that would be free of it.
The researchers found that, in a world without climate change, the recorded WBGT values would have been virtually impossible. They would have occurred, at most, once every 5000 years.
And even in today’s world, such conditions are estimated to be extremely rare – once every 200 years – although uncertainty remains given the extreme nature of the phenomenon.
The researchers also tested the impact of El Niño, a natural warming phenomenon in the Pacific, which would only cause a slight cooling of temperatures.
World Cup matches, including France’s July 4 encounter with Paraguay in Philadelphia, are expected to record WBGT temperatures above 82°F (28°C) at kickoff. FIFPRO, the players’ union, has requested that the matches be postponed.
