Hurricane Beryl is causing significant damage in parts of the Caribbean, highlighting the role of climate change. With maximum sustained winds exceeding 160 mph (257 km/h), it became the earliest category five Atlantic hurricane in over a century. Previously, only Hurricane Emily on July 16, 2005, reached this intensity in July.
The causes of individual storms are complex, making it challenging to attribute specific instances to climate change fully. However, exceptionally high sea surface temperatures are a key reason for Hurricane Beryl’s power. Typically, such strong storms develop later in the season after the seas have warmed through the summer.
Hurricanes generally require sea surface temperatures of at least 27°C to develop. As shown on the map below, waters along Hurricane Beryl’s path have been much warmer than this. Warmer seas lead to more powerful hurricanes, as storms can absorb more energy, resulting in higher wind speeds.
“We know that as we warm the planet, we’re warming our sea surface temperatures as well,” explains Andra Garner, an assistant professor at Rowan University in the US. “And we know that those warm ocean waters are a critical fuel source for hurricanes.”
In the main Atlantic hurricane development region, the ocean heat content – the energy stored throughout the water column – is at levels typically seen in September. This period is usually the peak of the Atlantic hurricane season, as sea surface temperatures are at their highest.
The chart below illustrates this, showing that most major hurricanes occur in late August and September, with earlier ones being rare. While a category five hurricane this early in the season is unprecedented, its strength fits into the broader pattern of how these storms are changing in a warming world. Although the number of hurricanes is not increasing, a higher proportion of them are expected to reach the highest categories globally as temperatures rise.
“Although it is uncertain to what extent climate change contributed to the early formation of Hurricane Beryl, our climate models suggest that the mean intensity of hurricanes will increase in the future due to enhanced global warming,” explains Hiroyuki Murakami, a research scientist at NOAA’s Geophysical Fluid Dynamics Laboratory.
Another factor this year is regional weather patterns. In the eastern Pacific, El Niño conditions have recently ended. El Niño inhibits strong hurricane formation in the Atlantic due to its impact on atmospheric winds. The opposite phase, La Niña, favors Atlantic hurricane development. Currently, there are “neutral” conditions, but La Niña is expected later this year. This likely transition, coupled with rising sea temperatures through July and August, raises concerns about more powerful hurricanes forming later in the season.
“Hurricane Beryl sets a precedent for what we fear will be a very active and dangerous hurricane season, impacting the entire Atlantic basin,” says Ko Barrett, Deputy Secretary-General of the World Meteorological Organization.
In May, the US weather agency NOAA warned of an “extraordinary” Atlantic hurricane season, forecasting between four and seven major hurricanes (category three or above) between June and November. On average, the Atlantic experiences three major hurricanes a year. Meteorologists and climate scientists have also noted how quickly Hurricane Beryl strengthened. It took just 42 hours to go from a tropical depression (with maximum sustained winds of 38 mph or less) to a major hurricane (above 111 mph).
“What makes Beryl particularly notable is that it […] intensified the fastest from a tropical depression to a hurricane [of any Atlantic hurricane in June or early July],” explains Shuyi Chen, a professor of atmospheric science at the University of Washington. Hurricane Beryl exemplifies “rapid intensification,” where maximum wind speeds increase quickly, leaving communities with less time to prepare.
The frequency and magnitude of these rapid intensification events in the Atlantic appear to have increased in recent decades. “Unprecedented as Beryl is, it actually aligns with the kinds of extremes we expect in a warmer climate,” Dr. Garner says. “As we warm the planet, we’re essentially stacking the deck of extreme events against ourselves, making events like Hurricane Beryl not only possible but more likely.” “It’s up to us to reduce our emissions to change that story.”
