If you’re a worker in Sydney not getting much done today there’s a reason for that, and it’s going to keep getting worse, writes Thom Mitchell.

It’s 42 degrees in Sydney at the time of writing, and I’ll admit I’m having a hard time staying focused. But it’s unlikely I’m alone, given extreme heat can shave nearly a third off workers’ productivity.

Sound like a poor excuse? Not quite. According to a synthesis report released by the Climate Council earlier this year, “only 41 per cent of fully acclimatised Australian workers can operate at or near full capacity on days over 35°C, and nearly a third perform at less than 70 per cent capacity.”

Which is particularly bad news given, as the report notes, “hot days have doubled in the last 50 years and heat waves have become hotter, last longer, and occur more often”.

And if your boss doesn’t kill you as you drip unproductively at your desk or building site, a heatwave might. Mortalities from heatwaves are projected to double over the next 40 years in Australian cities, the Climate Council said, and they’re already the lead killer amongst natural hazards.

According to the Climate Council report, “Ground-breaking scientific research that can now tell us how much influence climate change has on a single heatwave or heat record has shown that many of the most extreme weather events, such as Australia’s record hot year in 2013, were virtually impossible without climate change.”

In other words, Sydneysiders and their employers can look forward to more days like today.

Bureau of Meteorology data shows that the sweltering temperatures Sydney’s workers are currently toiling away under are nearly 20 degrees above the November mean maximum. And certainly, it does feel mean.

In a separate study out of Charles Darwin University earlier this year, more than 1,700 employed Australians were asked about how they feel heat stress impacts their work. It found heat stress related reductions in workplace productivity were as high as they are for many chronic diseases.

It estimated the annual cost to be as high as $728 per person, and $6.9 billion across the economy for workers aged between 18 and 65.

“Climate change has a significant impact on labour productivity, particularly in Australia where people experience extreme heat, but few studies have estimated its economic cost,” said lead researcher Dr Kerstin Zander.

Professor Stephen Garnett also worked on the paper, and said that previous studies had been based on physiological models of heat exposure, whereas their study yielded “a valuable insight into the psychological impacts”.

“One surprising finding was that heat affected the productivity of office workers as much as it did outdoor workers, with 70 per cent of those surveyed saying heat stress had reduced their productivity at work,” Prof Garnett said.

“It is feeling hot that affects productivity, not necessarily whether they are experiencing unusual conditions.”

At 42 degrees Celsius, it’s fair to say most Sydneysiders are feeling the heat.

According to the study, 7 per cent of the workers surveyed had skipped work at least once in the last year because it was just too hot. I think that’s fair enough, too.