Australia's plan for net zero includes "dangerous" soil carbon assumptions and could be too expensive without a market mechanism, according to agricultural emissions experts.
Richard Eckard, professor of agriculture at the University of Melbourne, said he was concerned about some of the assumptions around land use. Photo: Photononstop
The warnings come as the federal government formally adopts the long-term target of net zero by 2050.
Prime Minister Scott Morrison will confirm Australia's commitment to the target at next week's climate summit in Glasgow.
Richard Eckard, professor of agriculture at the University of Melbourne, said he was concerned about some of the assumptions around land use.
"The reliance on soil carbon - I would even go so far as to say - it is a dangerous assumption," Professor Eckard said.
"It is kind of asking farmers to lock up their soil to bail out the fossil fuel industry.
"This notion that the soil carbon on farms can bail out the fossil fuel industry is quite fanciful.
At the end of the day, in a country that is 22 percent more variable than any other country in the world, soil carbon is 90 per cent about rainfall.
"You cannot bank the future on something that is dependent on rainfall and climate change is challenging that exact rainfall.
"Under a changing climate, I think we will be lucky to hold on to the soil carbon we have got let alone increasing the amount we can store."
Current policy won't get Australia to net zero
Recent research from the Future Fuels CRC looked specifically at reducing greenhouse emissions under a number of different scenarios, including a 60 per cent emissions reduction as well as 100 per cent target.
The report concludes that without a market-based signal for reducing emissions, the federal government would need to develop a "massive greenhouse gas emissions program" which cannot be afforded by bio-sequestration.
Essentially under the existing policy framework, a plan to reach net zero using hydrogen or electrification would see the government need to directly fund emissions reduction offsets.
The research estimates that this will end up costing in the vicinity of $15.5 billion to $16.4 billion per year.
Can farmers play a key role?
Mike Young, professor of Water, Energy and Environmental Policy at the University of Adelaide, said agricultural emissions were part of the problem and he was worried the value in carbon sequestration could be overstated.
"About half of our greenhouse gas emissions aren't associated with energy production," he said.
"Things like air-conditioning, agriculture, fertilizer, use of other sources of gases.
"And we thought we'd be able to just pay farmers to increase stocks or carbon to offset that [but] we found it was way too expensive.
"Ultimately, getting to net zero and staying at net zero is going to involve something else."
One of the technologies Professor Young suggests might help is carbon capture and storage (CCS), a technology that is being strongly questioned by the likes of mining magnate Andrew Forrest.
When pressed on whether there is enough scientific evidence that direct extraction or carbon capture and storage can be part of the solution Professor Young is resolute.
"It's expensive still, but so is making hydrogen" he said.
"People are saying in the US and elsewhere, they can do direct air capture at the moment, for about $200 a tonne.
"We modelled it at $100 a tonne, which assumes there would be significant breakthroughs and reductions in cost.
"But there are lots of opportunities in Australia to store CO2 underground using carbon capture and storage."
ABARES estimates the changing climate is already costing every farmer $30,000 per year in lost revenue.
Regional and rural areas 'no worse off'
While much of the past two weeks has hinged on whether the Nationals would support net zero in exchange for commitments for regional communities.
As part of the commitment, the federal government will ask the productivity commission to conduct five-yearly reviews assessing the economic impacts of the net-zero target on regional and rural communities.
However, early modelling by the Future Fuels CRC shows regional economies will not be affected.
"This is the first-ever attempt to model regional detail and we modelled what would happen region by region," Professor Young said.
It uses modelling to measure the impact of emissions targets in the Pilbara, the "iron triangle" in South Australia, and in regional Queensland among other locations.
The researchers found that, common to all scenarios, neither GDP per capita nor GDP generally declined in any Australian state or territory or in any of the 11 regions examined.
"Every part of Australia will experience an increase in jobs and an increase in regional income as we go to net zero. We were really surprised by this," Professor Young said.
"No area's going to be worse off, according to our estimates."
According to researchers, this is not due to any energy policy levers but simply a function of population increases with a forecast Australian population of around 37 million in 2050.
Energy Minister Angus Taylor said Australians would be nearly $2000 better off on average in 2050, than if the country failed to take action.
However, Mr Taylor has not revealed the government's modelling to support its net zero commitment.
"It's a plan for net zero, not absolute zero," he said.
The Prime Minister Scott Morrison pitched the plan to regional Australians.
"I can say to rural and regional Australians this is a good plan for you, it's a good plan for all Australians," he said
"And we're confident that it is going to secure your future, that you can plan for your future with confidence.
"So, I'll be taking this plan to COP26 for our target to achieve net zero by 2050."
- ABC