JO KHAN. We still have time to act on climate change — but records will tumble for next 20 years regardless of emissions: study (ABC News)

Jun 25, 2019

Our last summer was the hottest on record in Australia, and we can expect the record breaking weather to continue for at least the next 20 years, new climate change research has found.

Regardless of action on climate change, monthly temperature records will continue to be smashed for the next two decades, but what happens beyond then depends on whether or not we reduce our greenhouse gas emissions.

Immediate action to drastically reduce emissions would rein in the temperature record-breaking from around 2040, according to a study published in Nature Climate Change today.

But the rate of record-smashing will continue to rise throughout the 21st century if emissions keep increasing at the current rate.

Two different climate futures

Hearing how fire agencies across the country were struggling to manage unprecedented bushfires motivated lead author Scott Power from the Bureau of Meteorology to undertake the study.

“I thought, well how often we are going to face these unprecedented conditions in the future?”

Dr Power used 22 climate models to project how often we would break temperature records in the next century, under both high (business as usual) and low emissions scenarios.

“We found that you’re going to smash and set records far more frequently if global greenhouse gas emissions continue to rise the way they have been,” Dr Power said.

Under a business as usual emissions scenario — which is well beyond what the Paris Agreement hopes to achieve — 60 per cent of the world will set at least one new monthly temperature record every year by the end of the century.

However, under a low emissions scenario — which aims to limit warming to 2 degrees Celsius as per the Paris Agreement — the likelihood of setting high monthly temperature records drops markedly from around 2040, to as low as 10 per cent by the end of the century.

“Reducing global emissions is going to prevent the rate of temperature record setting and smashing from increasing all the way through to the end of the century,” Dr Power said.

“But those benefits [of reducing emissions] don’t really kick in for another 20 years so.”

Climate adaptation still needed

While large emissions reductions are key to avoiding smashing temperature records all the way to the year 2100, it is critical that areas such as fire management are able to adapt to unprecedented hot weather conditions for a few more decades, Dr Power said.

“People and plants and animals are going to have to cope with the regular occurrence of these extreme temperatures over the next two decades, because we won’t get the benefits from reducing emissions for a while,” he said.

High temperature records are already being set regularly in Australia.

Not only will new records being set happen more often if emissions are not reduced, but the margins records are broken by will also get bigger, said Sarah Perkins-Kirkpatrick, a climate scientist from the University of New South Wales, who was not involved in the study.

“Even if we reduce our emissions tomorrow it’s still going to take some time for the temperature effects to really come into play.

“So that means we do have to adapt.”

The impact of climate change and record temperatures will continue to be strongest in the tropics, according to Dr Power.

“The rate at which people will experience these unprecedented conditions is higher in the tropics and in developing countries than it is in developed countries,” he said.

“And the benefits of cutting emissions sooner are even bigger for developing countries.”

A record a month without drastic action

Despite a reduction in greenhouse gas emissions being the only action that may prevent parts of the planet becoming unliveable in the future, Australia’s emissions continue to rise.

Dr Perkins-Kirkpatrick said that it would be “a miracle” if the best-case emissions scenario happened.

“What we do really does make a difference,” she said.

“Ultimately this planet’s climate will stabilise if we reduce our emissions, and then those record temperatures won’t be as extreme.”

Without action to drastically reduce emissions we will be breaking at least one monthly temperature record every year by the end of the century, Dr Power said.

“To be honest it’ll probably be a record nearly every month.”

But he adds that it would be detrimental to focus on emissions reduction alone.

“We will also need to adapt to more unprecedented weather conditions over the coming decades.”

This article was published by ABC News on the 18th of June 2019. 

Jo Khan is a science journalist and broadcaster. She produces Off Track on Radio National and is also an online reporter for the RN Science unit. Before moving into science journalism, she was a coral reef scientist. You can follow her on Twitter: @JoannaAKhan

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