‘Running a fever’: What you should know about ‘maritime’ heat waves, weather extremes

Ocean temperatures that are much hotter than normal this summer have alarmed scientists and raised the prospect of accelerated global heating.

From record-shattering heatwaves to unprecedented forest fires, the summer of 2023 is one for the record books — and it’s still only August.

Last month was the hottest in recorded history, as firefighters responded to hundreds of wildfires in Canada, tourists grappled with extreme heat in Europe, and residents of Phoenix, Arizona endured an entire month of temperatures that went beyond 43 degrees Celsius each day.

It’s not just weather extremes on land that are a cause for concern.

Giant stretches of the world’s oceans are experiencing unheard-of hot temperatures, alarming oceanographers, coral researchers and atmospheric scientists the world over.

Oceans have been absorbing 90 per cent of the excess heat that gets emitted into the atmosphere from the buildup of greenhouse gases, including those that are the result of industrial-scale burning of fossil fuels by humans to power the world economy.

But all that heat energy, absorbed by vast expanses of water, can eventually make its way into the atmosphere, accelerating the vicious cycle of planetary heating — and leading to more weather extremes, including more intense fires, fiercer storms and more gruelling heatwaves.

“This is exactly the kind of thing that leads to stronger rain events, stronger storms,” says Ted Scambos, a senior research scientist at the University of Colorado Boulder. “Not necessarily more hurricanes or more storms, but very often stronger storms and bigger rain events when they occur.”

The oceans, in other words, have been doing a lot of the heavy lifting in terms of mitigating the escalating crisis of global heating. But there is only so much heat they can absorb.