How Climate Change Amplified Category 5 Hurricane Melissa — New Studies Show Stronger Winds and Heavier Rain

How warming amplified Hurricane Melissa

Category 5 Hurricane Melissa was an astonishing storm that shattered historical records and struck the western end of Jamaica last week. A cluster of rapid-attribution studies released in the days after the storm conclude that human-caused warming likely helped push Melissa to become unusually intense.

Scientists stress that climate change does not "cause" a single disaster by itself, but a warmer planet increases the odds of more powerful storms. Three independent research teams — ClimaMeter (Europe), the Grantham Institute (London School of Economics), and Climate Central (U.S.) — all found that Melissa would likely have been weaker and produced less rainfall without decades of anthropogenic warming.

All three groups agree Melissa was intrinsically rare and could have formed in a cooler climate: Category 5 hurricanes have struck the Caribbean and Florida for centuries. Melissa tied the Atlantic record for strongest landfalling storm, matching the 1935 Labor Day Hurricane that devastated much of the Florida Keys.

Still, researchers note the world is measurably warmer than it was a century ago. Tropical-cyclone hot spots such as the Caribbean Sea and parts of the Atlantic are now warmer, supplying extra heat energy to storms. Warmer sea-surface temperatures and a moister atmosphere make it easier for hurricanes to reach higher wind speeds and to produce heavier rainfall.

Key findings from the three studies:

• ClimaMeter estimated Melissa's sustained winds (near 185 mph) were about 10% stronger because of recent warming and that rainfall was roughly 10% higher than it would have been in a cooler climate.
• The Grantham Institute reported similar results: roughly 7% higher wind speeds and about 16% more rainfall attributable to anthropogenic warming.
• Climate Central estimated that warming may have boosted peak wind speeds by as much as 10 mph.

"We often see that different attribution studies come up with slightly different percentages but what we do see is that the ballpark number is typically the same," said Gabriele Mesori, a ClimaMeter co-author and professor of meteorology at Uppsala University.

These analyses come from the growing field of rapid attribution, where teams apply peer-reviewed methods to produce fast, transparent estimates shortly after an event rather than waiting years for a traditional study. The studies focused primarily on wind speed and rainfall — the hurricane impacts scientists have the most physical confidence in linking to warming.

"Things like rainfall and wind speed — those are simple. We have physical evidence to explain why climate change affects them," said Brian Soden, professor of atmospheric sciences at the University of Miami's Rosenstiel School. "Those are the impacts we have the greatest confidence in."

Beyond wind and rain, research has explored other potential climate-related changes: shifts in the timing of the season, clustering of storms, and slower storm motion. Melissa moved unusually slowly, crawling across the Caribbean at roughly 2 mph for days and briefly stalling while dropping feet of rain over parts of Haiti and Jamaica. Some studies suggest climate change could be contributing to slower storm translation speeds, but experts say the evidence is not yet robust.

"I just don’t think there’s enough research done on that to understand why there’s this slowing of storms," Soden said. "Hurricanes are relatively uncommon; you need large datasets and careful statistics to show a change in motion." Mesori and his team likewise could not confidently link Melissa's sluggish pace to warming and emphasize the need to separate natural variability from climate-driven effects.

One notable result from the Grantham analysis is that a "Melissa-type" storm is now about four times more likely in 2025 than it would have been a century ago, before large-scale fossil-fuel emissions warmed the atmosphere. Researchers emphasize this raises the probability of such extreme storms — it does not mean Melissa required climate change to occur.

Rising seas also increase the baseline for storm surge, meaning similarly strong storms will push more water onshore than in the past, compounding coastal risk. Overall, the three studies add to a growing body of evidence that a warmer world produces stronger, wetter hurricanes, while underscoring remaining uncertainties about storm frequency and motion.

Bottom line: Rapid-attribution studies consistently indicate that human-caused warming made Hurricane Melissa stronger and wetter than it likely would have been otherwise, increasing both peak winds and rainfall. However, some aspects — notably the storm's slow motion — remain uncertain and require further research.