Some experts see them as the next step in preventing climate chaos. Others think they shouldn’t be mentioned.

Carbon dioxide removal (CDR) technologies, which remove carbon from the atmosphere, are one of the most controversial climate research topics.

The IPCC’s latest climate science study rekindled the debate about CDR last month. The analysis showed that absorbing and storing carbon dioxide, however expensive, may help keep global temperatures safe.

Scientists and politicians disagree. Some argue research should prioritize technology.

Others advise against trusting untested technology before we have fully installed reliable low-carbon technologies like renewable energy.

Climate envoy John Kerry expressed his concerns. “Some scientists suggest that there could be an overshoot [of global temperatures, beyond the 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,” he said. The threat is irreversibility.

The former UK government chief scientific adviser Sir David King fiercely disagrees. Because the globe is almost certain to exceed the global target limit of 1.5C over pre-industrial levels, he believes several types of CDR will be needed, along with ways to “repair” the climate, such refreezing the ice caps.

“We are already 1.35C above pre-industrial levels,” he claimed. “The Arctic is already more than 3C above the pre-industrial average.”

New technological startups show that many companies and investors regard CDR as a business opportunity. These startups are investigating “scrubbers” that chemically remove carbon dioxide from the air, “biochar” that creates fertilizer from burning wood waste without oxygen, and carbon capture and storage (CCS), which liquefies and pumps carbon dioxide into underground geological formations. The IPCC report has encouraged investment and acceptance.

“The next decade will require a massive scale-up to meet IPCC carbon removal targets. “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 business that hopes to utilize microorganisms to trap carbon in soil.

“The IPCC report makes clear that the window of opportunity is closing quickly, highlighting the urgent need to reduce greenhouse gas emissions,” said Ben Rubin, executive director of the Carbon Business Council, which represents many CDR specialists. The paper states that gigatonnes of carbon removal are needed to repair the climate. “Innovators are finding cost-effective and responsible ways to deploy carbon removal.”

Scientists and governments argued over the IPCC report’s controversial part until the last minute. After hours of haggling, scientists and government representatives from any UN member who wants to participate added a few CDR remarks to the final 36-page summary for policymakers, which distills the main messages.

CDR and CCS were prioritized by Saudi Arabia and other oil-producing nations. The summary included nine CDR and several CCS references.

Saudi Arabia brought 10 seasoned negotiators.

The references upset many scientists, campaigners, and green specialists. They worry that suggesting carbon dioxide removal is possible could mislead people. Most CDR technologies are unproven, limited, expensive, and take years to develop.

“We need to challenge the idea that we have to do less now, because we can do more later, with technofixes,” said Center for International Environmental Law climate and energy program director Lili Fuhr. It’s risky.”

“My feeling about CDR is that we should pretend it is not an option,” said IPCC lead author Friederike Otto, senior lecturer at Imperial College London’s Grantham Institute. Assume CDR is impossible. We don’t have a scaleable technology, so we should construct our policy as though CDR isn’t an option.”

She said CDR may be a harmful distraction and questioned if it was wise to invest in technology with uncertain future advantages when viable emissions-reduction methods were not being deployed quickly enough. “CDR has already been used to dither and delay,” she claimed.

Otto said: “It’s very important to highlight that we still can keep to 1.5C – we have the knowledge and tools to do it. We lack political will and urgency.”

King agrees that some scientists are skeptical of CDR, but he believes it is necessary due to inaction. “[Those who object] are taking the exact position I took in 2015, when I was leading UK global negotiations,” he remarked. “But we can’t waste time.”

King, who is working with Cambridge University’s engineering department to refreeze the Arctic, notes that the IPCC report found only a narrow opportunity for the world to limit heating to 1.5C, which requires massive greenhouse gas reductions in the next few years, which is unlikely.

He argued the IPCC did not go far enough on CDR. “I expect 1.5C by the end of the decade. The IPCC’s claim that lowering emissions will keep us below that level is wrong. We must remove our atmospheric carbon. It may be expensive, but losing our civilization is worse.”

    Leave a Reply

    Your email address will not be published. Required fields are marked *