Removing CO2 From Atmosphere Vital To Avoid Catastrophic Tipping Points, Leading Scientist Says

10bn tonnes must be captured from the air every year to limit global heating to 1.7C, says Johan Rockström of the Potsdam Institute for Climate Impact Research.

Removing carbon from the atmosphere will be necessary to avoid catastrophic tipping points, one of the world’s leading scientists has warned, as even in the best-case scenario the world will heat by about 1.7C.

Johan Rockström, one of the chief scientific advisers to the United Nations and the COP30 presidency, said 10bn tonnes of carbon dioxide needed to be removed from the air every year even to limit global heating to 1.7C (3.1F) above preindustrial levels.

To achieve this through technological means, such as direct air capture, would require the construction of the world’s second-biggest industry, after oil and gas, and require expenditures of about a trillion dollars a year, scientists said. It would need to be done alongside much more drastic emissions cuts and could also have unintended consequences.

Rockström was among several leading climate experts who spoke at a first public event for the Science Council, which was set up as an advisory body by the Belém COP30 presidency.

Chris Field of Stanford University said that despite the overshoot, the world should retain the 1.5C target because the longer and higher the world remains beyond that, the greater the risk of more dangerous tipping points in the Antarctic, Greenland, ocean circulation, and the Amazon rainforest.

Tim Lenton, a tipping point expert at the University of Exeter, outlined the range of risks that are already close. Still greater dangers lie ahead, he warned, particularly if there is a collapse of the Atlantic Meridional Overturning Circulation system of ocean currents.

“This would trigger other tipping points,” Lenton said. “We must do everything we can to prevent this.”

Thelma Krug, coordinator of the council, noted that the UN’s main climate science body, the Intergovernmental Panel on Climate Change (IPCC), has begun a study on different mechanisms for carbon removal. Rockström added that the Potsdam Institute’s modelling had shown that, even with ambitious carbon removal and strong government actions to reduce emissions, it was still only possible to limit heating to between 1.6C and 1.8C.

Despite the enormous costs involved, Rockström said the alternative was more devastating droughts, fire storms, and suffering.

Christiana Figueres, one of the architects of the Paris Agreement, expressed optimism that global decarbonization remains unstoppable. “Honestly, the decarbonisation of the global economy is irreversible,” she said. “Momentum is building into the point where it is simply unstoppable, with or without the US.”

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