Massive heatwave hits region five times larger than Australia

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The World Meteorological Organisation’s (WMO) State of the Climate in the South-West Pacific report released earlier this week found 2024 was the hottest year on record for the region, up 0.48 degrees on the average for the last three decades.

It also found that almost 40 million square kilometres of ocean – an area about five times the size of Australia – were subjected to heatwaves for much of the first half of the year.

A map showing marine heatwaves in the South-West Pacific in 2024. — Most of the South-West Pacific was subjected to intense marine heatwaves last year. (World Meteorological Organisation)

“Most of the ocean area of the South-West Pacific region was affected by marine heatwaves of strong, severe or extreme intensity during… particularly the equatorial region of the Maritime Continent and the western Pacific,” the report states.

“During the months of January, April, May and June 2024, nearly 40,000,000km2 of the region’s ocean was impacted by marine heatwaves.”

Pointing to heatwaves in Western Australia, where temperatures got to within touching distance of 50 degrees last February, and floods across much of the country, as well as severe weather in other nations in the region, the WMO said the changing climate is posing a “serious risk” to public health, lives and livelihoods.

“Unprecedented ocean warming, sea level rise, and extreme weather are endangering lives, ecosystems, and economies across the region – especially in coastal and island communities,” it said.

Lake MacLeod, a salt lake near the WA coastal town of Carnarvon. — Lake MacLeod near the WA coastal town of Carnarvon, which last year hit 49.9 degrees. (Peter De Kruijff)

“2024 saw record sea-surface temperatures and near-record ocean heat content, with marine heatwaves affecting over 10 per cent of the global ocean.

“On land, extreme heat, intense rainfall, and a historic cyclone season caused devastating impacts.”

Speaking ahead of today’s World Oceans Day, Monash University climate expert Associate Professor Shayne McGregor said Australia is particularly vulnerable to changes in the ocean.

“Australia is exposed to climate variability that is largely ocean-driven,” he said.

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“These modes of climate variability, like the El Niño-Southern Oscillation, influence our rainfall, heatwaves and fire risk.

“Recent ocean changes, which include rising sea levels, increasing occurrence of marine heatwaves and changes to ocean currents, have already had noticeable impacts.

“These changes aren’t just environmental; they’re economic and personal.

“They affect water security, food production, insurance costs, and even how we plan our energy infrastructure.”