For some, CDR is crucial to staying below 1.5C. Others say it should not even be on the table. Why is it so controversial?
John Kerry: relying on technology to remove carbon dioxide is ‘dangerous’
Fiona Harvey
Fiona Harvey Environment editor
Tue 25 Apr 2023 14.00 BST
Last modified on Tue 25 Apr 2023 14.53 BST
For some scientists, they are the inevitable next stage of staving off the existential threat of climate chaos. For others, they should not even be talked about.
Carbon dioxide removal (CDR) technologies, which provide a means of sucking carbon out of the atmosphere, are one of the hottest areas of climate research, but also the most controversial.
The debate over whether and how to develop CDR has been ignited by the release last month of the final section of the comprehensive review of climate science by the Intergovernmental Panel on Climate Change (IPCC). The report found that ways of capturing and storing carbon dioxide, though expensive, might play a role in trying t keep global temperatures within safe bounds.
But scientists and policymakers are divided. Some say the technology must be the immediate priority for research. Others urge caution, and warn against putting faith in untested technology before we have even fully deployed the reliable low-carbon technologies, such as renewable energy, that we already have.
icebergs
David King is working with Cambridge University’s department of engineering to try to find ways of refreezing the Arctic Photograph: NurPhoto/Getty Images
John Kerry, the US special presidential envoy for climate, talked of his concerns. “Some scientists suggest that it’s possible there could be an overshoot [of global temperatures, beyond the limit of 1.5C above pre-industrial levels that governments are targeting] and you could clawback, so to speak; you have technologies and other things that allow you to come back.
“The danger with that, which alarms me the most and motivates me the most, is that according to the science and the best scientists in the world, we may be at or past several tipping points that they have been warning us about for some time,” he said. “That’s the danger, the irreversibility.”
The former UK government chief scientific adviser Sir David King strenuously disagrees. He believes CDR of many kinds will be needed, along with the means to “repair” the climate, such as by refreezing the ice caps, because the world is almost certain to overshoot the global target limit of 1.5C above pre-industrial levels.
“We are already at 1.35C above pre-industrial levels today,” he said. “We are already experiencing massive warming in the Arctic, where it’s more than 3C above the pre-industrial average.”
A rash of new technology startups bears witness to the potential business opportunity that many companies and investors see in CDR. These fledgling companies are exploring everything from “scrubbers” that chemically remove carbon dioxide from the air, to “biochar”, which creates fertiliser fromburning wood waste without oxygen, and carbon capture and storage (CCS) by which carbon dioxide is liquefied and pumped into underground geological formations. They have taken the IPCC report as a spur to investment, and a stamp of approval.
“Growing carbon removal to be in line with the IPCC requires a massive scale-up in the next decade. Startups are meeting this climate challenge by developing a suite of approaches that can make a gigaton impact,” said Tania Timmermann, the chief technology officer of Andes, a company that plans to use micro-organisms to sequester carbon in soil.
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Ben Rubin, the executive director of the Carbon Business Council, which represents several CDR specialists, said: “The IPCC report makes clear that the window of opportunity is closing quickly, highlighting the urgent need to reduce greenhouse gas emissions. Reducing emissions is crucial but not enough: the report affirms tat gigatonnes of carbon removal are required to help restore the climate,” he said. “Innovators are actively working to meet this climate challenge, by finding cost-effective and responsible ways to deploy carbon removal.”
But the key section of the IPCC report, which ignited the controversy, was fiercely fought over by scientists and governments up until the last moments before the document was finalised. The handful of mentions of CDR in the final 36-page summary for policymakers – which distils the key messages and is compiled by scientists alongside government representatives from any UN member that wants to take part – were only inserted after hours of desperate wrangling.
Saudi Arabia and other oil-producing countries were most insistent that CDR and CCS should be included and emphasised. In the end, nine references to CDR were left in the summary, and several more to CCS.
“Saudi Arabia brought 10 very experienced negotiators,” said one person. “They tried to take out referencs to renewable energy and tried to insist that references to carbon capture should be in there instead of, or at least as well as, renewables.”