Hurricanes Helene and Milton wrought historic levels of destruction on the Southeast. Deadly floods occurred in North Carolina, widespread power outages ranged from Florida to Tennessee and high winds damaged or destroyed homes.
Several climate, hurricane and environmental experts from across the Southeast region told The Daily Gamecock that the storms brought on by the 2024 hurricane season were likely influenced by changes in the world’s climate.
The 2024 hurricane season
Nicholas Grondin, an assistant professor of environmental studies at the University of Tampa, was forced to evacuate to Daytona beach as Milton approached.
Helene and Milton, he said, were unusual storms that were exacerbated by climate change.
“The rainfall associated with Helene was almost certainly made worse by a changing climate, likely human caused, because a warmer atmosphere can hold more water vapor,” Grondin said. “And at the rate we're warming — we haven't seen this level of warming — and it correlates perfectly with greenhouse gas emissions.”
Greenhouse gas emissions are human produced gases that trap heat in the atmosphere, leading to global climate change, according to The Environmental Protection Agency.
The rainfall from Milton was 20% to 30% worse than it would have been without human induced climate change, according to a study by World Weather Attribution. The study used rainfall data and models of Milton to determine its figures.
Helene’s high rainfall resulted in significant flooding in Western North Carolina. A rainfall event prior to Helene saturated the ground in the area, said Gustavo Coelho, a professor of water resources at Furman University. Saturated soil prevents water from seeping into the ground and can cause flooding, he said.
“If you have a saturated soil and then have a storm, you're going to have much more water flowing over the surface,” he said.
Milton had the strongest hurricane wind speeds in the Gulf of Mexico since 2005, according to The National Oceanic and Atmospheric Administration.
The storm's wind speeds increased by 95 mph in the span of 24 hours, raising it from a category one to a category five, according to NOAA. The phenomenon is called rapid intensification.
Warm waters in the Gulf of Mexico were perfect for this process, Grondin said.
“Any developing system that moves over a warm Gulf of Mexico, and with a lack of wind shear — which there was — it's like throwing a match into a pool of gasoline,” he said. “It's just going to explode.”
Future hurricanes
Hurricanes in the Atlantic may continue to increase in strength due to climate change, said Cary Mock, a professor of climatology and hurricane researcher at USC.
“Potentially there could be more strong category fours or category fives, and perhaps more wetter storms, like maybe about 20% wetter than what they would be if it wasn't as warm,” he said.
Warmer ocean temperatures will drive the strengthening of future hurricanes and increase their rainfall, Grondin said.
In contrast, the number of storms that develop may decrease. A warmer climate produces greater wind shear, the differences in wind speeds at different levels of the atmosphere. Strong winds in higher levels can destroy the structure of hurricanes and weaken them, according to NOAA.
“Wind shear acts to weaken storms, and with a warming climate, current modeling studies say we should have fewer or weaker storms, because we expect with the warming climate, we would have an increase in wind shear,” Grondin said.
Climate change may also shift the tropical climate zones of the Atlantic, possibly influencing hurricane development and paths.
“We expect (climate change) also to slightly disrupt some of the general circulation of the planet with an expansion of the tropics,” Grondin said. “So areas that are tropical we expect to expand a little bit, and we expect the polar areas to contract a little bit. You can make an argument that odd tracks that we haven't seen before may become a little more likely with an expanding tropical zone.”
Other possible effects
Climate change has the potential to impact more than just hurricanes.
For coastal residents and communities, sea level rise may be a major concern, said Claudia Benitez-Nelson, an associate dean in USC's College of Arts and Sciences.
“So melting glaciers, Greenland, off of Antarctica, that's increasing sea level rise that's fundamentally impacting our state — Charleston, Myrtle Beach — all along our coast,” she said.
Charleston already experiences regular floods, and these will be worsened by sea level rise, she said. Major hurricanes have impacted the Charleston area before, such as Hurricane Hugo in 1989.
Charleston is a major tourism hub and economic engine for South Carolina, she said. And Flordia's circumstances are similar, Grondin said.
“That's a big risk for Florida, particularly south Florida, Miami in particular, as well as I would say the Keys and other areas that have a more flatter Coast area, swampy places in particular,” he said.
Sea level rise may worsen storm surge from hurricanes.
“I would say that the biggest threat is the rising sea level,” Mock said. “And so that means when you do get a hurricane, the storm surge would be higher than what it usually would be.”
Increased average temperatures pose risks as well, Benitez-Nelson said. Hotter days mean less time people can spend outside, increasing the likelihood of drought and changes to growing seasons for plants, she said.
“There's kind of this temperature range that we talk about for the number of days that South Carolina gets too hot, and so we've increased that number of days by about 20 to 25 days,” she said.
As with Milton, warm sea temperatures can cause the rapid intensification of hurricanes.
If actions are not taken to limit climate change, then tough choices will have to be made, Benitez-Nelson said. This may include moving homes away from coasts and adjusting fresh water usage, she said.
“We've got to make changes now, or we need to think about adaptation and sustainability, and what are we going to do to adapt, and what are we going to do to sustain,” she said. “That's going to mean we have to make some tough choices.”