Carbon capture nets 2 billion tonnes of CO2 each year — but it’s not enough

More than 2 billion tonnes of carbon dioxide is being removed from Earth’s atmosphere each year, according to an analysis of global efforts to capture and store the greenhouse gas.

But this will not be enough to meet the Paris Agreement goal of limiting global warming to less than 2 °C above pre-industrial temperatures, even with pledges from governments worldwide to increase carbon dioxide removal (CDR) rates and invest in new technologies.

The report, called The State of Carbon Dioxide Removal, provides the first global estimates of the total amount of carbon that is being sucked out of the air each year, and predicts how much this will have to increase under various emissions scenarios. It was published on 19 January.

“If we want to have a robust strategy for meeting the Paris Climate goal,” says co-author Jan Minx, “we need to limit the dependence on CDR, and this means we need to get on track with our emission reductions.” Minx is a climate researcher at the Mercator Research Institute on Global Commons and Climate Change, Berlin.

He and his co-authors collated information on current CDR, as well as governments’ goals to reduce national emissions and to deploy removal technologies.

They estimate that the current global rate of CDR is around 2 billion tonnes per year (see ‘Current carbon removal’). This is “perhaps larger than many people think”, says co-author Steve Smith, a climate scientist at the University of Oxford, UK, but “it is still a lot smaller than the net total emissions”.

The vast majority of CDR uses conventional methods, managing land so that it absorbs and stores atmospheric carbon dioxide — for example by planting trees, restoring damaged forests or replenishing soil.

About 0.1% of carbon removal — around 2.3 million tonnes per year — is performed by new technologies. These include power plants that generate energy but capture and store emissions, such as bioenergy with carbon capture and storage facilities; ‘direct air capture’ technologies that extract carbon dioxide from the atmosphere through methods including chemical reactions; and biological charcoal, or ‘biochar’, which absorbs net carbon from the atmosphere when added to soil. The study estimates that with all the CDR projects currently under development, the amount of carbon dioxide captured in this way could rise to 11.75 million tonnes per year by 2025.

Sizeable shortfall

The analysis found that even with government pledges to increase the amount of carbon removed from the atmosphere, there is a gap between projected CDR and what is needed to meet the Paris climate goals.

To limit global warming to less than 2 °C above pre-industrial temperatures, the report estimates that by 2030, the world will need to remove a further 0.96 billion tonnes of carbon dioxide each year, compared with 2020. By 2050, this will have to rise even more, to around 4.8 billion tonnes above 2020 levels. As it stands, governments worldwide have proposed an increase of only between 0.1 billion and 0.65 billion tonnes of CDR per year by 2030 and 1.5 billion to 2.3 billion tonnes per year by 2050.

“The size of that gap already rests on the assumption that we’re going to have rapid emissions reductions,” says Smith. Therefore, “deep emission cuts will be needed alongside any type of carbon removal”, says Sara Nawaz, an environmental researcher at the American University in Washington DC.

“We need to aggressively develop and scale up CDR, particularly those novel methods,” says Minx. The report says that on average across global emissions scenarios, CDR using innovative methods will need to increase by a factor of 1,300 by 2050 to limit warming to 2 °C.

Global public investment in CDR research was around US$4.1 billion between 2010 and 2022, and investment in new CDR technologies was $200 million between 2020 and 2022. But “governments could have supported CDR [and] invested in them much more for quite a while already, but they haven’t”, says Nils Markusson, an environmental social scientist at the University of Lancaster, UK. “To understand why that is, or why that might be the future and what to do about it, we really need to pay explicit attention to the politics and the political economy surrounding CDR.”

doi: https://doi.org/10.1038/d41586-023-00180-4