Sir David has told the BBC the government's support for coal mines showed the world it did not care about the environment, while noting the destruction caused by bushfires.

He says the "moment of crisis" has come in the fight against climate change, warning that government targets are not enough to save the planet.

The government has turned its focus on climate change adaptation and resilience in the wake of the deadly bushfires, but is backing in coal exports.

Home Affairs Minister Peter Dutton argues that reducing Australia's coal exports won't end up helping the environment.

"(Australia) stopping exports of coal to India or to China will mean that they will source it from other countries," he told Nine's Today show on Friday.

"It means emissions will go up, so there's no benefit to the environment and we would lose $70 billion from our economy."

Labor leader Anthony Albanese agrees.

"If you stopped exporting coal immediately, then that would not reduce global emissions because there's enough displacement from other coal exporting countries to take up that position," he told reporters in Sydney.

"And that coal will produce higher emissions rather than less emissions."

The Morrison government intends to use carryover credits to meet the Paris target, of a 26 to 28 per cent reduction on 2005 emissions levels by 2030.

Its use has been condemned on the international stage, with one of the creators of the Paris agreement saying it goes against the point of the deal.

It's not yet known what impact emissions from the bushfires will have on Australia's emissions, with the blazes emitting up to an estimated two-thirds of annual carbon dioxide levels.

The long-term impact depends on forest regrowth and whether or not it would "re-absorb" the carbon, meaning this year's spike in levels could be evened out.

The Department of Environment and Energy says this reflects practices used by the European Union, Canada and the United States.

"The methodology smooths the impact of emissions variability due to natural disturbances by reflecting the long-term carbon storage in forests, which generally, over time and in the absence of new disturbances, re-absorb carbon to balance that carbon emitted during the fire," a department spokeswoman told AAP.

The centrepiece of the government's plan to reduce emissions is by paying companies for reduction projects through the Emissions Reduction Fund.

Given the fires are ongoing, the full impact on projects remains to be seen.

"Thus far, the majority of fire activity has occurred in areas without ERF projects," the spokeswoman said.

Australian Associated Press