Photo: Onslow, a small beachside town in the Pilbara, 1,400 kilometres north of Perth.(ABC News: Tom Edwards)
The Conversation January 14, 2022 1.30pm AEDT
Senior Lecturer in Climate Science, The University of Melbourne
While Australians are used to summer heat, most of us only have to endure the occasional day over 40℃.
Yesterday though, the temperature peaked at 50.7℃ in Onslow, a small Western Australian town around 100km from Exmouth.
Remarkably, the town sits right next to the ocean, which usually provides cooling. By contrast, the infamously hot WA town of Marble Bar has only reached 49.6℃ this summer, despite its inland location.
If confirmed, the Onslow temperature would equal Australia’s hottest on record set in Oodnadatta, South Australia, in January 1960. It would also mark only the fourth day over 50℃ for an Australian location since reliable observations began.
Unfortunately, this extreme heat is becoming more common as the world heats up. The number of days over 50℃ has doubled since the 1980s. These dangerous temperatures are now being recorded more often – not just in Australia but in cities in Pakistan, India and the Persian Gulf. This poses real threats to the health of people enduring them.
Where did the heat come from?
Hitting such extreme temperatures requires heat to build up over several days.
Onslow’s temperatures had been close to average since a couple of heatwaves struck the Pilbara in the second half of December. So where did this unusual heat come from?

In short, from the bakingly hot desert. South to south-easterly winds blew very hot air from the interior of the state up to Onslow. The wind came from an area that has had little to no rainfall since November, so the very hot air was also extremely dry.
Dry air kept the sun beating at full intensity by preventing any cloud cover or storm formation. The result? The temperature rose and rose through the morning and early afternoon, and the temperature spiked at over 50℃ just before 2.30pm local time.
Aren’t we in a cooler La Niña period?
Australia’s weather is strongly linked to conditions in the Pacific Ocean. At the moment we’re in a La Niña event where we have cooler than normal ocean temperatures near the equator in the central and east Pacific.
La Niña is typically associated with cooler, wetter conditions. But its effects on Australian weather are strongest in spring, when we had unusually wet and cool conditions over the east of the continent.
During summer the relationship between La Niña and Australian weather usually weakens, with its strongest impacts normally confined to the northeast of the continent.
During La Niña we typically see fewer and less intense heatwaves across much of eastern Australia, but the intensity of heat extremes in Western Australia is not very different between La Niña and El Niño.
The pattern of extreme heat in Western Australia and flooding in parts of Queensland is fairly typical of a La Niña summer, although temperatures over 50℃ are extremely rare.

Climate change is cranking up the heat
Should these temperatures be a surprise? Sadly, no. Australia has warmed by around 1.4℃ since 1910, well ahead of the global average of 1.1℃.
In northern Australia, summer-average temperatures have not risen as much as other parts of the country, because summers in the Top End have also got wetter. That’s in line with climate change models.
When the conditions are right in the Pilbara, however, heat is significantly more extreme than it used to be. Heat events in the region have become more frequent, more intense, and longer-lasting, just as in most other regions.
Most of us have chosen not to live in Australia’s hottest areas. So you might think you don’t need to worry about 50℃ heatwaves. But as the climate continues to warm, heatwave conditions are expected to become much more common and extreme across the continent.
In urban areas, roads and concrete soak up the sun’s heat, raising maximum temperatures by several degrees and making for dangerous conditions.
Even if we keep global warming below 2℃ in line with the Paris Agreement, we can still expect to see our first 50℃ days in Sydney and Melbourne in coming years. In January 2020 the Western Sydney suburb of Penrith came very close, reaching 48.9℃.

As you know, it’s going to be very hard to achieve even keeping global warming below 2℃, given the need to urgently slash greenhouse gas emissions in the next decade.
As it stands, the world’s actions on emission reduction suggest we are actually on track for around 2.7℃ of warming, which would see devastating consequences for life on Earth.
We already know what we need to do to prevent this frightening future. The stronger the action to reduce greenhouse gas emissions globally – including by major carbon emitting countries such as Australia – the less the world will warm and the less Australian heat extremes will intensify. That’s because the relationships between greenhouse gas emissions, global temperatures and Australian heat extremes are roughly linear.
You may think Australians are good at surviving the heat. But the climate you were born in doesn’t exist any more. Sadly, our farms, wildlife, and suburbs will struggle to cope with the extreme heat projected for coming decades.
Let’s work to make this 50℃ record an outlier – and not the new normal.
“We MUST respect this earth - it is all we have
Claudio Dametto - South Australia
“I will always Vote to Preserve Our World.
Liam McGregor - Western Australia
“A simple message that even a politician can understand
Felicity Crombach - Victoria
“Please show you care about our future generations!!
Phil Harmer - New South Wales
“Save our world , Life & health before profits.
Kerry Lillian - New South Wales
“Close down all coal mines and Do not mine gas . Make these Companies
Daniel Johnson - New South Wales
“We want carbon free energy!
Edan Clarke - New South Wales
“Feels good to be taking a voter action step
Beaver Hudson - New South Wales
“Great Initiative. Let’s Hold elected officials Accountable to their bosses, us!
John Paul Posada - New South Wales
“We need actions not words we need honest democratic govt We need a pm
Bob Pearce - South Australia
“Thank you for this great resource. I was feeling helpless. Even this small step
Silvia Anderson - Victoria
“If political parties continue receiving political donations, we will rarely have politicians working for
Dan Chicos - New South Wales
“I only vote for people who will take urgent action to restore a safe
Susie Burke - Victoria
“Current government is not representing the opinion of the majority of Australian to meet
Neil Price - Tasmania
“We are fighting to rescue our kids' future from those who seek to steal
Vanessa Norimi - Queensland
“No time to waste Now or Never My vote is for NOW
Rosalie White - Victoria
“I am only 9 but I already care
Ava Bell - New South Wales
“From New Lambton Uniting Church - Caring for our world is a moral imperative.
Niall McKay - New South Wales
“Our federal govt is an International climate Embarrassment - its about time they stepped
Oriana Tolo - Victoria
“Vote earth this time!
Sue Cooke - Queensland
“We are in one on the wealthiest countries in the world. we have the
rowan huxtable - New South Wales
“The climate Emergency is the public health opportunity and urgent priority of the 21st
Mike Forrester - Victoria
“If they want my vote they better act now
Barbara McNiff - New South Wales
“We need to act locally now for the earth. Our only home. Vote Earth
Anne Miller - New South Wales
“I often look at the places I've known all my life and see how
Jim Baird - New South Wales
“Strike one For people power!!! Democracy might prevail outside the current cronyism that faces
Lorraine Bridger - New South Wales
“Our federal politicians Are Afraid to make action on climate change a major election
Jennifer Martin - New South Wales
“climate election, let's go!
Fahimah Badrulhisham - New South Wales
“Great to see this website that is a focus on action for climate change
Lynette Sinclair - New South Wales
“Let’s show politicians and the Murdoch media that climate change is by far the
Jane Aitken - Australian Capital Territory
“If you want to stay in power You need to take action to stop
Jane Bulter - New South Wales
“We are all that stands between terminal climate change and the vulnerable. We are
Carol Khan - Queensland
“We need a Government that Believes this is real and not taking money from
Ken Gray - New South Wales
“I'm voting for my childrens future
Anneliese Alexander - New South Wales