Treasurer Jim Chalmers has confirmed his first budget, due out on Tuesday, will include a major analysis of the impact of climate on Australia's economy.

Emission reduction targets of 43 per cent by 2030 and net zero by 2050 became law last month, setting the carbon budget.

"It's pretty simple maths," environmental markets expert Andrew Macintosh told AAP.

"There's only a certain amount of emissions that we can emit if we want to keep global warming to 1.5 to two degrees."

Countries signed up to the Paris Agreement make a pledge known as a nationally determined contribution (NDC) that sets out the national emissions budget for 2021-2030.

Labor's upgraded NDC for Australia limits emissions to 4381 million tonnes across those years, according to the document submitted to the United Nations.

The document also promises to "restore" the Climate Change Authority, which had its funding slashed under successive coalition governments, with Tuesday's budget set to back a bigger workforce.

Carbon Market Institute (CMI) transition expert Kurt Winter said a carbon budget sends a strong signal to invest in decarbonisation and abatement.

"Whether the carbon budget is a symbolic tool depends on how the government integrates it into the legislative framework that governs Australia's climate policy suite," he told AAP.

Australian Conservation Foundation (ACF) campaign director Paul Sinclair said a national carbon budget would support better decisions.

"Budgets need to count what matters," Dr Sinclair said.

Costing the impacts of global warming as well as the economic opportunities that flow from budget spending on renewable energy and repairing nature would be critical, he told AAP.

ACF research shows half Australia's GDP has a moderate to very high direct dependence on nature, and indirectly every dollar that flows through the economy depends on natural systems.

But scientists warn Australia will exceed its carbon budget on the current trajectory, meaning the speed of emissions reduction must accelerate.

"We are already out of our budget, or pretty close to running out, which is why a lot of people say, and legitimately say, that our target needs to be in excess of 43 per cent," Prof Macintosh said.

"Mathematically, we have a problem."

Some say Australia isn't doing its fair share of the global response to climate change.

Pacific neighbours are adamant emissions cuts must be deeper to help limit global warming to 1.5 degrees.

Under a 1.5 degree carbon budget, Australia would need to go net zero by 2035, according to the Grattan Institute.

Australia's biggest emitters are covered by a safeguard mechanism that will tighten allowed emissions over time, forcing industrial plants and the electricity grid to end their dependence on fossil fuels.

Under the mechanism, emitters can make changes by using new technologies and processes, or buy carbon credits - each offsetting one tonne of emissions, or pay a penalty for exceeding the limit.

"The centrepiece tool is the safeguard mechanism," Prof Macintosh said.

But rather than divvying up one pot of emissions for the entire economy, industry wants a more targeted approach.

"The government may need to develop sector-specific approaches as a first step," CMI's Mr Winter said.

A sector-by-sector budget could sit within a national carbon budget, with baselines for emissions set by the regulator in reference to the legislated carbon budget.

"This could provide additional assurance that the mechanism is driving science-aligned abatements consistent with Australia's fair share of global action," he said.

Australian Associated Press