When we crank up the air conditioning on a hot summer’s day, jump in the car to head to the beach or stick some hamburgers on the barbecue, hurricanes are likely the last thing on our minds.
Most of us only think about storms when one is heading towards us and we start to make preparations to stay safe.
Yet each of these everyday activities contributes — even on a tiny scale — to the climate change that may influence the strength and behaviour of hurricanes affecting Bermuda in the future.
The overwhelming majority of scientists agree that human activity is driving climate change.
The fossil fuels we burn for our air conditioning and vehicles are a major source of greenhouse gas emissions, while beef is one of the most emissions-intensive foods in the world.
Those emissions drive global warming, including increased sea temperatures, which increase the potential for stronger hurricanes.
Andy Moore, a natural catastrophe modeller at Arch Reinsurance, explained that waters near the ocean’s surface have warmed significantly globally and in the Atlantic Basin over the past 20 to 30 years.
The same is true for Bermuda: the oceans surrounding the island are about 0.75°C warmer now than in the late 1900s.
Mr Moore said: “All else being equal, warmer oceans provide additional energy to hurricanes, giving them the potential to become stronger.
“The warming we have seen thus far has raised the maximum potential intensity of storms in our vicinity around 5mph.”
‘New normal’
Francis Kredensor, Bermuda Weather Service’s deputy director, said while there was “no clear signal” on climate change having an impact on the number of hurricanes, we may already be seeing overall tropical cyclone intensity and associated rainfall increasing.
He said many interconnected factors went into hurricane frequency and intensity, so it was hard for researchers to “definitively” say that any changes to date were due to the overall effects of climate change.
“But the fact that two-thirds of Atlantic hurricane seasons since 1995 have been assessed as being ‘above normal’ or ‘extremely active’ points to us being in a new normal, whatever the cause,” he added.
Climate Central, an independent group of scientists researching climate change, tracks sea temperatures daily on its Climate Shift Index.
Data from the index in mid-May gave the ocean temperature around Bermuda as 22.4°C, which was 1°C hotter than usual for the date.
The index suggested climate change made the unusually warm ocean conditions “at least three times more likely”.
Mark Guishard, chief operating officer at the Bermuda Institute of Ocean Sciences and the author of the 2022 report Climate Change and Bermuda, said oceans absorbed around 90 per cent of the excess heat produced by human-induced warming.
“At Bios, we’ve been monitoring the warming of the surface of the Atlantic Ocean near Bermuda for over 70 years,” he said.
“Future model projections indicate that upper ocean warming will accelerate in the coming decades.”
Does the evidence point to more intense storms reaching Bermuda in future?
Dr Guishard said: “The energy available to support hurricane development is accumulating.”
Mr Kredensor said the single biggest factor affecting storm intensity was ocean temperatures so “all else being equal, as waters continue to warm, stronger storms are increasingly likely and they’re likely to reach further north”.
Mr Moore agreed. He said: “The Atlantic Basin has already seen a significant trend in the proportion of Atlantic hurricanes that become major hurricanes [category 3 to 5] and this proportion is forecast to increase further.”
He said the heightened risk was also expected in Bermuda and was detailed in a 2024 government report on climate change by Smith Warner International Ltd.
That study concluded that Bermuda’s future would “likely be characterised by more intense hurricanes”, bringing higher winds and greater rainfall.
It said a likely increase in rainfall rate of between 20 and 33 per cent was projected, particularly near the hurricane’s core, by the century’s end.
Mr Kredensor said: “There is increasing confidence in research pointing towards climate change causing increases in overall storm intensity going forward, as well as heavier rains associated with tropical cyclones.”
Bermuda is ‘exceptionally vulnerable’
The Government has acknowledged the challenges posed by climate change, including warmer seas.
Former home affairs minister Walter Roban said in November 2024: “Though Bermuda’s contribution to global greenhouse gas emissions is minimal, we find ourselves on the front lines of climate impacts.
“Like other small island and developing states, Bermuda is exceptionally vulnerable to climate impacts.”
The Smith Warner study cited figures from a 2021 report by ocean climate scientist Samantha Hallam and others, which analysed tropical cyclone intensity and potential intensity in the subtropical Atlantic around Bermuda from an ocean heat content perspective.
The authors found the maximum wind speeds for hurricanes in Bermuda had increased 30 knots from 1955 to 2019. They measured an average increase of 7.7 knots per decade from 1980 to 2009.
The Smith Warner report noted that “in recent years, Bermuda has experienced several significant storms that caused widespread flooding and damage”.
It said 2014’s Hurricane Gonzalo caused “extensive damage” and the same year saw the “first season in recorded history to feature two hurricane landfalls in Bermuda”.
No one can say exactly what Bermuda’s hurricane seasons will look like in 10, 20 or 30 years’ time — but the evidence suggests we must prepare for stronger storms.
Dr Guishard, in his 2022 report, said one more major storm per decade in our region was projected by a few modelling studies.
The Smith Warner report flagged up the “necessity to revise building codes to address this escalating threat in the medium to long term”.
Kim Smith, executive director of Bermuda Environment Sustainability Taskforce, said we could all do our part on climate change but the threat we face needs both individual and collective efforts.
“What we need from the Government is for there to be a national policy and action plan for the mitigation of and adaptation to climate change,” she said.
“In the absence of that, we might just be shooting in the dark.”
