A new National Academy of Sciences report calls for a "substantial research initiative" to quickly advance technologies that directly remove carbon dioxide from the atmosphere.
Why it matters: It's a stark recognition that expansion of zero-carbon energy sources will not be enough to meet the internationally recognized goal of holding the global temperature rise below 2°C/ 3.6°F, let alone 1.5°C/ 2.7°F — which are recognized benchmarks for avoiding some of the most catastrophic effects of climate change.
What they found: "Recent analyses of economically optimal solutions to the climate problem have concluded that [negative emissions technologies] will play as significant a role as any mitigation technology," the report states.
It envisions 10 billion tons of CO2 emissions-removal needed annually by roughly mid-century, an amount that doubles by 2100.
This Associated Press piece nicely puts that 10 billion number in context:
"That’s the equivalent of about twice the yearly emissions of the U.S.," AP notes. "Last year the world put nearly 37 billion metric tons of carbon dioxide into the air, and emissions have been rising."
Where it stands: The panel of scientists that wrote the report conclude that while some options already exist, they're not ready to get the job done at the scale needed — thanks to vast amounts of land needed and other constraints — and without unintended harms.
They include various types of land-use changes — like forest-planting — and soil management practices that increase CO2 uptake, as well as bioenergy with carbon capture and storage (which would require vast amounts of cropland at scale).
So a lot more research is needed to improve those options, reduce their negative effects and cut costs.
- Meanwhile, 2 other major options that have "essentially unlimited" capacity — direct air capture and carbon mineralization — have barely been explored, they note.
- They caution that CO2 removal is not a replacement for other mitigation strategies or emissions cuts, but rather a piece of the solution.