CANBERRA, AAP – As a new global study estimates fossil fuel air pollution is responsible for nearly one in five deaths worldwide, regionally based government politicians continue squabbling over local emissions reduction targets.

The research led by Harvard University estimated exposure to particles from fossil fuel emissions accounted for 18 per cent of deaths globally in 2018.

The study found eastern North America, Europe and Southeast Asia – regions with the highest concentrations of fossil fuel related air pollution – have the highest mortality rates.

UK universities were also involved in the study, which used 3D modelling to divide the world into a grid so pollution levels could be looked at look on a closer scale compared to previous studies.

“Our study adds to the mounting evidence that air pollution from ongoing dependence on fossil fuels is detrimental to global health,” Eloise Marais from University College London said.

“We can’t in good conscience continue to rely on fossil fuels, when we know that there are such severe effects on health and viable, cleaner alternatives.”

Prime Minister Scott Morrison has not committed to net zero by 2050, but says it’s his preference to achieve the target.

But Nationals senator Matt Canavan and colleagues such as Barnaby Joyce reject the idea, having long opposed action on climate change because they are sceptical of the science.

Deputy Nationals leader David Littleproud insists the backbenchers won’t prevent progress to net zero emissions.

“Because I sit in this thing called cabinet and we’re the executive part of the government, and I can tell you that from the prime minister down, there is a commitment to making sure we can find a pathway to this and that we’re honest about it,” he told the ABC on Tuesday evening.

There is also speculation the grumbling backbench group are kicking up a stink to throw Nationals leader Michael McCormack off balance.

Senator Canavan will not be satisfied by excluding agriculture from the long-term carbon target, which is being floated as a potential bargaining chip to win over the Nationals.

“I don’t support any move to a radical, crazy, loopy, net zero emission policy which would shut down our economy,” he told Nine on Wednesday.

Senator Canavan insists the open rebellion has not been confected to ramp up pressure on Mr McCormack.

“I don’t care if Michael McCormack is our leader, Barnaby Joyce, or Mr Squiggle. I will always be against ideas that cost jobs in regional areas,” he said.