Extreme marine heatwave as waters off Sydney set to break temperature records – “It appears now to be reaching record levels and will likely be the hottest January on record”

By Graham Readfearn
4 January 2022

(The Guardian) – Waters off Sydney are undergoing an extreme marine heatwave with temperatures likely at their highest levels on record for January.

Satellite data is showing the ocean surface off the coast of Sydney at 3C above normal, with swimmers and surfers reporting conditions that feel more like February and March than early January.

Prof Moninya Roughan, an oceanographer at the University of New South Wales and an expert in marine heatwaves, said the hottest water was covering an area of about 200sq km.

Roughan is waiting until new data becomes available in the coming weeks from a long-term ocean temperature monitoring station at Port Hacking, where temperatures have been observed since the 1950s.

But she said: “It appears now to be reaching those record levels and will likely be the hottest January on record. It’s an extreme marine heatwave.”

She said there were three factors behind the extra heat.

Global heating was pushing up background temperatures in the ocean, a La Nina weather system was helping transport warmer waters south, and atmospheric conditions were also playing a role.

“Marine heatwaves are having severe consequences on ecosystems and they can kill habitats,” she said. […]

Prof Rob Harcourt, a marine ecologist at Macquarie University in Sydney, regularly surfs off Sydney beaches.

“It’s been over 21C in the water for over a month now. Everyone that surfs has been talking for weeks about how it’s felt more like February and March than December [when the heat started to build].” [more]

‘Extreme marine heatwave’: waters off Sydney set to break January temperature records