According to a new report from leading climate experts, technology to remove the planet-warming greenhouse gas CO2 from our atmosphere must be ramped up urgently.

The report states that large cuts in CO2 emissions alone will not be enough to limit global warming and that nature alone will not remove enough of it from the air. CO2 is the primary gas responsible for warming the planet and is emitted when fossil fuels such as gas and oil are burned.

The report’s lead author, Dr Steve Smith from Oxford University, states that “to limit warming to 2C or lower, we need to accelerate emissions reductions. But the findings of this report are clear: we also need to increase carbon removal.” The report suggests that many new methods with potential are emerging.

The consensus among scientists is that the world is warming primarily because emissions of CO2 (estimated at 33 billion tonnes in 2021) far exceed the amount that is being removed (this report suggests two billion tonnes a year). To fully achieve “net zero” there will need to be some CO2 removal, so-called “negative emissions”, to compensate for sectors that can’t easily decarbonize.

Currently, almost all of the world’s CO2 removal occurs through natural processes, primarily through plants and trees taking in CO2 from the air and the soil absorbing and storing it. However, there are limits to what nature can do. Some optimistic scenarios suggest that natural CO2 removal could be doubled by 2050, but that’s still only about 4 billion tonnes of CO2 a year.

The “The State of Carbon Dioxide Removal” report argues that to limit global warming in the future, there needs to be an investment in developing technological solutions now.

The report cites several new methods at different development and deployment stages, but they currently make up a small fraction of the world’s CO2 removal. These methods include BECCS, which involves incorporating CO2 capture into biomass-based electricity generation, and other options such as extracting carbon from the air before being stored in the ground, using specially treated charcoal (biochar), and “enhanced rock weathering” based on the carbon removal that occurs with natural erosion.

The report stresses that removing CO2 should not be seen as a “silver bullet” to tackle climate change but that meeting the UN’s climate goals will require technology and nature to reduce greenhouse gas levels.

However, the report also notes that the use of CO2 removal technologies has critics who doubt that they can be cost-effective and fear they can be an excuse to delay the transition from fossil fuel use.