Hurricanes are enormous heat engines of wind and rain that feed on warm ocean water and moist air — and scientists say the climate crisis is making them more potent.
The proportion of high-intensity hurricanes has increased due to warmer global temperatures, according to a UN climate report released in August. Scientists have also found that the storms are more likely to stall and lead to devastating rainfall and they last longer after making landfall.
“We have good confidence that greenhouse warming increases the maximum wind intensity that tropical cyclones can achieve,” Jim Kossin, senior scientist with the Climate Service, an organization that provides climate risk modeling and analytics to governments and businesses, told CNN.
“This, in turn, allows for the strongest hurricanes — which are the ones that create the most risk by far — to become even stronger,” he added.
When hurricanes are stronger and move slower, they dump more rain, meaning more damage and flooding in the areas they pass over.
A 2020 study published in the journal Nature also found storms are moving farther inland than they did five decades ago. Hurricanes, which are fueled by warm ocean water, typically weaken after moving over land, but in recent years they have been raging longer after landfall. The study concludes that warmer sea surface temperatures are leading to a “slower decay” by increasing moisture that a hurricane carries.
For every fraction of a degree the planet warms, according to the UN report, rainfall rates from high-intensity storms will increase, as warmer air can hold more moisture. Earlier this week, what had been Tropical Storm Fred dumped more than 10 inches of rain on western North Carolina, according to the National Weather Servicewhich pushed the Pigeon River near Canton nine feet above flood stage and killed at least four people.