Global warming fueling stronger storms

When Hurricane Melissa roared across the Caribbean early this week, tearing through Jamaica with Category 5 winds, it was more than a natural disaster — it was a textbook example of how a warming planet is supercharging tropical storms.

Scientists say that human-caused climate change has made hurricanes like Melissa stronger, wetter and more destructive than ever before.

Melissa’s sudden intensification stunned even seasoned meteorologists. Within just 36 hours, it exploded from a tropical storm into one of the strongest hurricanes ever recorded in the Caribbean.

“The role climate change has played in making Hurricane Melissa incredibly dangerous is undeniable,” said Dr. Kerry Emanuel, a leading hurricane researcher at the Massachusetts Institute of Technology, in Cambridge, United States of America.

“The warmer the ocean, the more fuel available to hurricanes, and Melissa had an ocean that was record-hot beneath it.”

At the heart of Melissa’s strength was an ocean running feverishly warm. According to Climate Central’s rapid attribution analysis, the sea surface temperatures (SSTs) in the area where Melissa intensified were about 1.4°C above the long-term average.

This sounds like a meagre surge, but their report found that such extreme warmth was made hundreds of times more likely by human-caused global warming, the phenomenon that creates climate change.

In simple terms, hurricanes are heat engines, they draw their power from warm ocean water, which evaporates and rises, releasing energy that drives the storm.

When the water is warmer than usual, the process accelerates. Melissa’s intensification was so rapid that the U.S. National Hurricane Center described it as “unprecedented for the region”.

“Every tenth of a degree matters,” explained Dr. Friederike Otto, climate scientist, senior lecturer at Imperial College London and co-lead of World Weather Attribution, a network that studies climate change impacts.

“We’re now seeing storms intensify over record-warm waters that simply wouldn’t have existed without human-induced warming.”

The physics of a hotter, wetter atmosphere

The connection between global warming and hurricanes goes beyond heat. A warmer atmosphere holds more moisture, about 7% more water vapour for every 1°C of warming, according to the Intergovernmental Panel on Climate Change (IPCC).

That means hurricanes can dump vastly more rain. In Melissa’s case, the deluge was catastrophic. The storm stalled over Jamaica for nearly 12 hours, dropping more than 500 mm of rain in parts of the island, according to the Jamaica Meteorological Service.

Rivers burst their banks, sweeping away homes and crops.

“The combination of slower movement and higher moisture content is deadly,” said Dr. Michael Mann, climatologist and well-known American climate scientist and Presidential Distinguished Professor at the University of Pennsylvania.

“We’re seeing that combination more frequently in a warmer world, as jet streams weaken and
storms linger longer over land.”

Another climate-linked factor that made Melissa more devastating is sea-level rise. Global sea levels have risen by more than 20 cm since 1900, largely due to melting ice and the thermal expansion of warming seawater.

That seemingly small increase dramatically worsens coastal flooding.

During his tenure as secretary-general of the World Meteorological Organization (WMO), Taalas repeatedly highlighted the acute dangers faced by low-lying and island states from climate-driven sea-level rise and storm surges. 

In Jamaica, storm surges up to 3.5 meters inundated coastal towns like Black River and Savanna-la-Mar, while parts of Cuba’s southern coast experienced similar surges as Melissa moved west-northwest.

The human and economic toll

By October 28, regional authorities had confirmed at least seven deaths across the Caribbean — three in Jamaica, three in Haiti, and one in the Dominican Republic, with officials warned that the toll could rise as isolated communities are reached.

Thousands were injured or displaced, and more than 1.5 million people were affected across the region, according to the International Federation of the Red Cross (IFRC).

Economic losses are expected to exceed US$3 billion (roughly R55 billion), early assessments suggest. Analysts believe Jamaica’s World Bank catastrophe bond will trigger payouts to aid recovery, while insurers brace for billions in claims.

Melissa is part of a growing pattern. Since 2017, the Atlantic basin has seen a string of record-breaking storms, such as Harvey, Maria, Dorian, Ian, and now Melissa, each intensified by warmer seas.

According to National Oceanic and Atmospheric Administration (NOAA), the proportion of Category 4 and 5 hurricanes has increased since the 1980s, even though the total number of storms per year has not.

Adapting to a stormier future

Experts say adaptation and preparedness will be crucial for Caribbean nations as the climate warms further.

This includes stronger building codes, elevated infrastructure, mangrove restoration and better early warning systems.

“Jamaica and its neighbours are on the front lines of a crisis they did not cause,” said Inger Andersen, head of the Kenya-based UN Environment Programme (UNEP).

“The world must not only help them rebuild but also reduce emissions to prevent future Melissas.”

Most island nations and coastal areas face a daunting future, with strong possibilities of tropical storms and sea rise.

We know about all this very well, given what we saw n KwaZulu-Natal, where more than 500mm of rain fell in just two days, and in the Eastern Cape coast in April 2022.

The bottom line

The science is clear: warmer oceans, moister air and rising seas are combining to power hurricanes, making them stronger and more destructive than those of the past.

Hurricane Melissa, scientists say, is not an anomaly but a warning. Climate disasters such as Melissa are exactly what climate models have been predicting for decades.

Every new record storm is a reminder that the climate crisis is no longer a future threat; it’s here, shaping the weather we live through today.

Fortunately, science has given us recourse: mitigation and adaptation. But time is not on our side. We’d better get on with it, now.

• Dr Enock Sithole is the executive director of the South Africa-based Institute for Climate Change Communication.