Australians are among the most sceptical around the world that “climate disruption” is being caused by humans and that the costs of tackling it will be less than that of its impacts, according to polling across 26 countries.

Just 60% of Australians accept that “climate disruption” is human-caused, a fall of six percentage points from the previous poll 18 months earlier and well behind the global average of 73%, according to the results from French polling company Elabe.

The polling, commissioned by the international waste and recycling company Veolia, covers countries representing 67% of global greenhouse gas emissions, including US, UK, India, China and Japan.

The French polling results suggest higher levels of climate change denial, scepticism and uncertainty than surveys carried out only in Australia, although the methodologies and questions are not directly comparable.

Only 52% of Australians – the lowest percentage of any country – thought “the costs caused by the damage linked to climate disruption and pollution are going to be greater than the investments needed for the ecological transition of our societies”.

On average, 75% of people globally agree with the World Health Organization that climate change is the greatest health threat facing humanity, compared with only 63% of Australians.

Australia was following a “global trend” of a rise in “climate deniers”, the polling said, with half of all countries having between 26% and 43% of people disputing whether humans are responsible for global heating or whether it even exists.

The polling found 78% of Australians agreed “climate disruption” was happening, compared with 89% globally. Only residents of Ivory Coast had lower levels of acceptance than Australians, according to the polling.

One Nation voters were the most sceptical of any conservative or far-right voters in any country, the polling said, with only 31% agreeing “climate disruption” was human-caused.

About 29,500 people were surveyed around the world, including 1,000 people from Australia polled in November 2023 that were representative across age, gender income and are of residence.

Richard Kirkman, the chief executive of Veolia in Australia, said the survey results suggested “we need to do more work in telling the stories about the facts”.

“We don’t have the full support of the people and we don’t have the political support. We’re going to work harder on our communications because a lot of the actions people want to take anyway, regardless of climate change, such as producing electricity for a solar panel means less dust in the air and less pollution than from a coal-fired power station.”

Dr Graham Bradley, a research fellow at Griffith University who has led its annual climate action survey of more than 4,000 people, questioned whether the term “climate disruption” was commonly understood. That was a problem that could skew the results, he said.

The Griffith Climate Action Survey carried out in 2023 found 82% of Australians agreed the climate was changing. He said about a quarter of people either denied climate change was happening or were unconvinced that humans were causing it.

Around concerns on climate change, he said Australians were similar to Americans in their views “but somewhat behind many European countries”.

He said Australians were also well behind the views of scientists on the causes of climate change and about 20% of Australians did not trust what scientists told them.

The Australia Institute, a progressive policy thinktank, has run its annual Climate of the Nation survey since 2012.

In 2022, the last time the institute asked people about the causes of climate change, 70% of people agreed it was down to human activity.

Polly Hemming, the director of the institute’s climate and energy program, said they no longer asked people for their views on the causes of climate change in an attempt to avoid any damage from “remaining mired in that conversation”.

She said there was an “overwhelming” majority of Australians who said they were already feeling the effects of climate change. The number of people who had voted for pro-climate independents at the last federal election was further evidence Australians wanted action, she said.

As with the French polling, she said younger people were far more likely to follow the scientific evidence showing humans were causing climate change.

A rise in “conspiracy theories and attacks on our scientific institutions” could be influencing some people, Hemming said.

But she added that political messaging on the urgency of climate change was lacking across the main parties.

“Compare how politicians talk about national security or wars or economics of budget deficits,” she said.

“They put more emotion and urgency into those issues than they do for the climate crisis. Our surveys say people are concerned and they want action, but it’s not reflected in most of our media rhetoric or from our leaders or in action from industry.”