Hurricane Beryl has wreaked havoc in parts of the Caribbean, drawing attention to the role of climate change.
Its maximum sustained winds exceeded 160 miles per hour (257 kilometers per hour), making it the fastest Category 5 Atlantic hurricane in records dating back nearly 100 years.
In fact, only one Category 5 Atlantic hurricane has been recorded in July – Hurricane Emily on July 16, 2005.
The causes of individual storms are complex, making it difficult to fully attribute specific instances to climate change.
- author, Mark Pointing
- role, Climate Reporter
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However, it’s believed that the main reason Hurricane Beryl was so powerful was because of unusually warm sea surface temperatures.
Typically, such strong storms only occur later in the season after the ocean warms up over the summer.
For a hurricane to develop, sea surface temperatures generally need to be at least 27 degrees. As the map below shows, the waters along Hurricane Beryl’s path are much warmer than this.
All else being equal, warmer oceans make hurricanes more powerful because the storms can absorb more energy and their wind speeds increase.
“We know that as the planet warms, ocean temperatures will rise,” explains Andra Garner, an assistant professor at Rowan University in the US.
“And we know that warm ocean water is an important fuel source for hurricanes.”
In the main Atlantic hurricane generating regions, ocean heat content — the energy stored throughout the water column — has reached levels not typically seen until September.
Late summer is usually the time when the Atlantic hurricane season is most active, as sea surface temperatures are at their warmest.
This is illustrated in the graph below, where the dots represent major hurricanes from 1940 to 2024. As you can see, most major hurricanes occur in late August and September, and it is very rare for them to occur earlier than that.
While the number of hurricanes is not increasing, a higher proportion of hurricanes are expected to reach the most powerful category globally as temperatures rise.
“Although it is unclear to what extent climate change contributed to the early formation of Hurricane Beryl, our climate models suggest that the average intensity of hurricanes will increase in the future due to ongoing global warming,” explained Hiroyuki Murakami, research scientist at NOAA’s Geophysical Fluid Dynamics Laboratory.
Another factor to consider this year is local weather patterns.
Because El Niño affects winds in the atmosphere, it suppresses the development of powerful hurricanes in the Atlantic. The opposite phenomenon, called La Niña, promotes the development of hurricanes in the Atlantic.
Currently, the climate is “neutral,” neither El Niño nor La Niña, but it is expected to become La Niña later this year.
This likely transition, along with warmer ocean temperatures through July and August, has raised concerns that more powerful hurricanes could form later in the season.
“Hurricane Beryl is feared to be a harbinger of a very active and dangerous hurricane season that will affect the entire Atlantic basin,” said Cor Barrett, Deputy Secretary-General of the World Meteorological Organization.
Rapid intensification
Meteorologists and climate scientists have also noted how quickly Hurricane Beryl intensified.
It took just 42 hours for it to go from a tropical storm with maximum sustained winds of less than 38 mph to a major hurricane (greater than 111 mph).
“What is particularly noteworthy about Beryl is that […] The fastest tropical storm to hurricane [of any Atlantic hurricane in June or early July]”Shui Chen, professor of atmospheric sciences at the University of Washington, explains:
Hurricane Beryl is an example of “rapid intensification,” or a sudden increase in maximum wind speeds, which makes it particularly dangerous because communities have little time to prepare.
“Beryl is an unprecedented phenomenon, but it actually coincides very well with the extreme events we would expect in a warmer climate,” Dr Garner said.
“As the world warms, we are essentially ‘stacking’ extreme events against us, making events like Hurricane Beryl not only more likely, but more likely too.”
“We have a responsibility to reduce emissions to change this situation.”
Graphics: Erwan Rivolt