If CO2 Capture Doesn’t Improve, Climate Warming Could Increase by Another 0.5°C

The planet must eliminate hundreds of billions of tons of carbon dioxide to keep global temperature rise under 1.5°C this century. Even the less ambitious 2°C targets seem increasingly unattainable without substantial carbon capture and removal (CDR) technologies and urgent emission reductions.

The contentious role of carbon management technologies in meeting climate objectives has been debated for some time. According to the Intergovernmental Panel on Climate Change, a degree of carbon management is “inevitable” for reaching zero emissions required to stabilize global temperatures. However, it stresses that the necessary technologies have yet to be validated at the needed scale and emphasizes the risk of providing justifications for continued emissions.

“There’s an ongoing debate among scientists about whether CDR is essential or fundamentally unfeasible,” says Candelaria Bergero from the University of California, Irvine. “Some argue that CDR is unavoidable,” she adds.

To assess what is at stake, Bergero and her research team simulated the potential for global temperature increases to stay below 2°C while analyzing CO2 management across various emission scenarios aligned with the Paris Agreement targets. These scenarios incorporated both technological CDR methods like direct air capture and nature-based solutions such as tree planting, alongside varying carbon capture applications for emissions from power plants and industrial sources.

They determined that failing to capture or remove CO2 could lead to an additional 0.5°C rise in global average temperature by century’s end. Moreover, half of the carbon management predicted in the scenarios could induce about 0.28°C of warming, making it nearly impossible to restrict temperature increases to 1.5°C, even within frameworks that consider violations of that threshold.

While achieving 2°C warming targets might still be feasible without carbon management, researchers found that drastic emission reductions of 16% annually since 2015 are necessary. Such a rapid decrease appears unlikely given the increasing global emissions over the last decade, according to Bergero.

Furthermore, initiatives for scaling up carbon management aren’t progressing swiftly enough. According to Steve Smith at Oxford University, only 40 million tonnes of CO2 are currently captured and stored globally, and only about 1 million tonnes are removed directly each year.

“Like with other emissions reductions, countries frequently discuss ambitious long-term goals, yet lack immediate measures to implement the billions of tons of reductions necessary for these pathways to succeed,” he states.