Expert reaction: Carbon removal not fast enough

A new report released this week has found that carbon removal from the atmosphere is not moving fast enough to contribute to our efforts to tackle climate change.

Cutting greenhouse gas emissions is the key to limiting global warming, but experts say there is also an urgent need to suck hundreds of billions of tonnes of CO₂ out of the atmosphere if we want to limit warming to below 2°C, the goal of the Paris Climate Agreement.

However, the second State of Carbon Dioxide Removal report shows that just 2 billion tons of CO₂ is currently being removed from the atmosphere each year.

“We see some pretty strong parallels between where carbon dioxide removal is now and where renewables were 20 – 25 years ago,” Professor Gregory Nemet from the University of Wisconsin–Madison, USA, who co-authored the report, told journalists at the Australian Science Media Centre briefing.

“Back then renewables were a niche sector. Now, renewables are in a very different place. Some CDR [carbon dioxide removal] is already occurring, but it’s at a really small level.”

“We need near-term scale-up of carbon dioxide removal. And our estimates are on the order of 7 to 9 billion tonnes a year by 2052.”

Dr Annette Cowie, the NSW Government’s top climate scientist, who also worked on the report, said there are 15 different viable ways of sucking carbon from the atmosphere.

These are broadly split into ‘conventional’ methods, which include tree planting and wetland restoration, and ‘novel’ methods, which include carbon capture and storage and fertilising the oceans, she said.

The bulk of the CO₂ we’re currently sucking from the atmosphere is removed using conventional methods, “mostly reforestation”, says Cowie, adding that the contribution from the novel methods, including carbon capture and storage, is negligible. The report found these contribute less than 0.1% of the total.

However, one novel approach, biochar, is showing early promise, says Cowie. It involves burning plant matter in a low oxygen environment, “creating a product that’s essentially like charcoal”, and then adding it to soils.

“Biochar has more than doubled between 2021 and 2023,” she says.

Dr Morgan Edwards, also from the University of Wisconsin–Madison and a co-author of the report, says interest in novel CDR methods is increasing.

“We are seeing evidence of rapid expansion,” she says. “And…we’re seeing increasing coordination and knowledge sharing among different projects.

“Growth in investment in CDR startups has grown relatively rapidly…While conventional CDR still makes up a good chunk of these investments, we’re increasingly seeing many different kinds of novel CDR receiving large amounts of investment.”

However, while business is interested, the politicians may have some catching up to do, she added. “We see weaker evidence of policy-induced demand for carbon dioxide removal.”

Nemet summed up, saying: “We are seeing plenty of signs of progress in carbon dioxide removal. But large challenges remain.”

Carbon removal via bamboo biochar