Jan 14, 2021 - Energy & Environment

Breaking down the case for massively scaling up carbon removal tech

Illustration of a hand holding a vacuum, sucking carbon dioxide molecules out of the air. 
Illustration: Aïda Amer/Axios

New peer-reviewed research lays out a case for quickly launching huge global investments to scale up a nascent and currently quite an expensive weapon against climate change: machines that pull carbon dioxide from the atmosphere.

The big picture: The Nature Communications study is a stab at carefully gaming out a "crisis" response to a huge problem: Nations' pace of cutting new emissions falls well short of what's needed to limit temperatures in line with the Paris deal goals.

  • It explores the costs and effects of massively building out "direct air capture" that companies like Carbon Engineering and Climeworks hope to deploy at a commercial scale.
  • DAC is among the tech that can theoretically complement renewables, electric cars, hydrogen, efficiency, and other tech that mitigates new emissions.

Why it matters: One big takeaway is that DAC can play an important role in limiting warming. But at the same time, even a mammoth build-out would be nowhere near a silver bullet!

  • Much stronger efforts to stem new emissions are needed to prevent warming from blowing past the Paris goal of holding temperature rise to 1.5ºC-2ºC above preindustrial levels.
  • "[D]espite an emergency DAC program that removes prodigious amounts of CO2 (multiple gigatonnes annually by 2050 and rising substantially thereafter), concurrent deep mitigation of emissions...is still required to meet the Paris goal of limiting warming to 2ºC," it finds.

By the numbers: The study models a crash program — starting at over $1 trillion annually — that would eventually spur deployment of as many as 12,700 plants by the end of the century.

  • If that occurred alongside current emissions-cutting policy trends, temperatures would still rise 2.4–2.5ºC in 2100.
  • The study also finds that massive DAC deployment will consume lots of energy, consuming around 9%-14% of global electricity use in 2075.

The intrigue: The paper from UC-San Diego researchers melds detailed modeling of DAC scale-up with the realpolitik of emissions policy.

The authors note, in essence, that DAC finance could have political legs because it's not a threat to "entrenched" industrial interests.

A couple of other takeaways...

  • Don't wait. The temperature-limiting potential is worth the upfront money because near-term deployments "enhance future scalability."
  • A crash program to begin widespread deployment is still a climate win even when paired with power grids that rely on natural gas.
  • "[T]he near-term political approach to crash deployment should seek not to maximize CO2 removals but rather to deploy many plants to push the technology down the learning curve—which does not require fully decarbonized energy supplies," it notes.

Catch up fast: The study arrives amid growing attention to negative emissions, or carbon removal, technologies overall.

  • A major 2018 UN study found that pulling CO2 out of the atmosphere — not only cutting new emissions — will be an important tool for limiting global temperature rise.
  • Corporate giants including Microsoft, Amazon, Chevron and others are investing in various forms of negative emissions companies and projects.
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