American Physical Society - Cutting Emissions Likely Simpler, Far Cheaper Than Any "Carbon Removal" Technology
Ed. - And considering how it's apparently impossible to cut emissions, that's saying something.
EDIT
On Jan. 27, APS released a new report, “Atmospheric Carbon Dioxide Removal: A Physical Science Perspective,” that aims to answer this question. The four authors of the report — which was commissioned by the APS Panel on Public Affairs — are Washington Taylor of the Massachusetts Institute of Technology, Jonathan Wurtele of the University of California, Berkeley, APS Past President Bob Rosner of the University of Chicago, and APS President-elect Brad Marston of Brown University. The report summarizes the current state of available carbon dioxide removal (CDR) technologies and outlines recommendations for policymakers. Above all, the report emphasizes that in most cases, cutting current carbon emissions is easier and less costly than large-scale, engineered carbon dioxide removal efforts may ever be.
Human activity emits a total of 35 billion tonnes (35 gigatons) of carbon dioxide every year. Given the scale-up effort needed, removing just 1 gigaton would be the equivalent of a baseball batter “getting on first base,” says Marston. Yet at a time when the world is trying to bring as many new renewable energy producers online and drive down annual emissions, diverting clean electricity to carbon capture efforts would be “a huge ask,” he says. Even so, the report provides a summary of the carbon dioxide removal technologies in the pipeline, distinguishing between once-through and cyclic approaches, in part because the categories have distinct energy and material needs.
EDIT
Marston gives an example of a geothermally powered direct air capture plant recently brought online by Climeworks in Iceland. The plant made splashy headlines, billed as the first “large-scale” CDR plant in the world — “but you would need a million of those plants to absorb all of our annual carbon emissions,” says Marston.
Scaling up enough to have a meaningful impact would require a “mind-boggling” amount of effort and energy, he says. This is why the report also suggests ecosystem-based approaches, like reforestation and shifts in agricultural practices, which can be cheaper and help reverse the disruption of human activity. “Certain ecosystem-based CDR approaches could be our chance to get some part of this right,” Taylor says, despite factors that limit their potential, like conflict over land usage and difficulty guaranteeing long-term durability. For example, wildfires are unpredictable — and increasingly common.
EDIT
https://www.aps.org/apsnews/2025/02/the-daunting-physics-carbon-removal