Structures float in the water in the aftermath of Hurricane Fiona, in Rose Blanche, N.L., in September, 2022.JOHN MORRIS/Reuters
Porter Fox’s most recent book is Category Five: Superstorms and the Warming Oceans That Feed Them.
For centuries, mariners and coastal residents north of the 40th parallel have watched hurricanes ravage the Caribbean and the east coast of the United States, knowing that the odds of one making landfall on their shores at full force was slim. That is, until major storms such as Fiona arrived in 2022 – the most expensive extreme weather event in the history of Atlantic Canada, making landfall in Nova Scotia with the force of a Category 2 hurricane.
There have been others, their names appearing in headlines at a seemingly quickening pace: Igor (2010), Sandy (2012), Matthew (2016), Dorian (2019), Lee (2023), Beryl and Ernesto this year. More than three dozen tropical or subtropical storms have affected the shores of New Brunswick, Nova Scotia and Prince Edward Island in the past century – though most storms typically lost power as they approached, saving the region from full blown destruction as seen in New Orleans, Houston, Florida, and New York.
The primary deterrent safeguarding Canada’s shores – the only nation besides Russia to border three oceans – is that hurricanes draw their power from heat in the seas beneath them. Even with the warm Gulf Stream sweeping close to the Maritimes, cold water in the North Atlantic saps energy from storms, diminishing their strength and duration. In the opening decades of the Anthropocene, in which human activity has added an estimated .07 watts of heat to every square metre of land and water on the planet, the ocean is warming quickly, fuelling hurricanes to thresholds never-before-seen.
More Category 4 and 5 hurricanes hit North America from 2017 to 2021 than from 1963 to 2016. Since the 1970s, the likelihood of a hurricane developing into a Category 3 storm or higher increased by about 8 per cent per decade. The number of major hurricanes, including a new breed of “ultra-intense” Category 5 storms with winds of at least 190 miles an hour, is expected to increase by 20 per cent by 2100. Tropical cyclones today also last longer than they once did, and move slower, multiplying damage by many times.
A 2021 study by Yale University researchers explains another trend which Canadians should be aware of: how the warming ocean is drawing hurricanes northward. To model future hurricane tracks, analysts used sophisticated computer models to study the ancient past. During especially warm periods in Earth’s history, the ocean held enough heat to propagate hurricanes all over the planet, including the extreme north and south. The study suggests that we are on the cusp of a similar trend.
Other studies point to a possible westward migration of the North Atlantic tropical cyclone generation zone in the future, that could result in an uptick of landfalls along the North American east coast later this century. A recent study by Brooklyn’s First Street Foundation, an organization that measures the financial risks posed by climate change, shows how hurricanes will penetrate farther inland as well, affecting regions up to 1,000 miles inland.
Earth has seen plenty of climate swings, and storm behaviour has shifted in kind. During the “hothouse Earth” period three million years ago, palm trees, giant beavers and camels lived quite happily in the Arctic – and massive hurricanes roamed deep into the northern and southern hemispheres. What concerns hurricane experts and climate scientists today is the pace at which the ocean and its storms are changing. In the past, it typically took millenniums for subtle climate changes to take effect. Today, it is happening in half a century.
As with most anthropogenic catastrophes, the effects of rapid climate change on storms are compounding. Storm surge now rides on an elevated sea level, flooding Canadian coastlines with walls of water – including one that measured 30 metres tall – as in the case of Hurricane Fiona in 2022. Because the atmosphere holds around 8 per cent more water for every 3.6 C of warming, storms now carry vastly more precipitation – dumping up to 302 millimetres of rain in a day (Hurricane Harvey, 1999). One example of how the compounding forces of climate change are overwhelming northeastern coastlines: If Superstorm Sandy had occurred in New York in 1912 instead of 2012, it would have likely not flooded Lower Manhattan.
The trend is not strictly a Canadian or American problem. Once-safe regions in the Middle East, Africa and Asia now experience major tropical cyclones. Warming water off the coast of Europe in the past 20 years has opened the door to storms such as Hurricane Ophelia in 2017, which grazed Ireland with 119-mile-an-hour winds, and Storm Betty, which hit the same coast with an 80-mile-an-hour gale. On the night of Sept. 18, 2020, Subtropical Storm Alpha became the first subtropical or tropical cyclone to make landfall in mainland Portugal in recorded history, slamming into Figueira da Foz with 50-mile-an-hour winds and heavy rain before rolling south to Lisbon.
Nearly 2½ billion people on Earth live within 60 miles of the ocean, including 97 per cent of fishermen living and working in developing countries. Since 2002, the number of them affected by tropical cyclones has doubled to 560 million annually. By 2030, half the world’s population will live near the ocean, exposing billions to storms. To see the effect of these storms on populations, consider that in just the past 50 years tropical cyclones have killed an average of 43 people and cost US$78-million in damages every day.
Since the dawn of the Industrial Age and large-scale burning of fossil fuels, the oceans have absorbed 90 per cent of the excess heat humans created – and a quarter of the CO2 emissions blanketing the atmosphere. Without this buffer, global temperatures would be 25 per cent greater than they are today, affecting every corner of the world and most life on Earth. This unheralded service the ocean provided likely saved human civilization from certain extinction. And yet it comes with another cost: amplification of maritime storms.
Despite these statistics and observations, the climate crisis and intensifying storms remain more of a polemic social debate than an actual threat. Natural aberrations in weather over the decades have obscured the violent, pernicious signature of the crisis, leaving citizens with a milquetoast view of what a 1.5 C world will actually look like: T‑shirts in January … bikinis in Saskatchewan … air-conditioning in March. There is little talk of billions of acres of dried-out pine, larch and spruce forests burning in Canada; of the U.S. West running out of drinking water this century; of the coming food crisis; of the hundreds of millions of climate refugees putting pressure on international borders; of the disappearance of islands and coastlines as the rising sea retakes them; and the unimaginable power of amped‑up hurricanes arriving on unsuspecting coastlines with no dikes, seawalls or defences.
News of these disasters is delivered by harried weather forecasters clad in full-body rain suits while clinging to a seawall or signpost. The lead often describes unseasonably warm coastal waters, historic rainfall, rapid intensification and how all of this was nature’s response to the thick layer of greenhouse gases humans have wrapped around the atmosphere. If there is a silver lining, it is this: Hurricanes are now the courier. Their message is the very real cost of climate change.