The Technology Of Negative Emissions


A direct air capture facility in Zurich, created by the Swiss-based technology company ClimeWorks. JULIA DUNLOP / CLIMEWORKS

I was not aware that Elizabeth Kolbert has been writing for Yale e360 for the entire time we have been linking to her New Yorker work on this platform. And then some, because she started publishing there ten years ago. This is her 17th publication for Yale e360 and it can help a layperson understand in a relatively short read whether technology has any chance of accelerating our progress on climate change mitigation:

Climate Solutions: Is It Feasible to Remove Enough CO2 from the Air?

A U.S. scientific panel reports that technologies that take CO2 out of the atmosphere could be a significant part of a strategy to mitigate global warming. In an e360 interview, Stephen Pacala, the panel’s chairman, discusses how these fast-developing technologies are becoming increasingly viable.

Is there still time to avoid runaway climate change? To a large degree, the answer depends on the feasibility of “negative emissions” — techniques or technologies that suck CO2 out of the air. In the latest report from the Intergovernmental Panel on Climate Change (IPCC), all scenarios for limiting warming to 1.5 degrees Celsius depend on negative emissions technologies, or NETs. Most 2-degree scenarios also rely on negative emissions; many call for removing billions of tons of CO2 per year by mid-century.


Negative Emissions Technologies (NETs) range from low-tech, such as planting more trees, to more high-tech options, such as developing machines to scrub CO2 from the air. NATIONAL ACADEMY OF SCIENCES, 2018

Yet most NETs remain either untested or unproved. To help bridge this gap, the National Academies convened a panel of scientists and asked it to propose a research agenda. The panel considered several possible techniques, ranging from the low-tech — planting more trees — to the high-tech — developing machines to scrub CO2 from the sky. It also looked at a hybrid technology that has become known as bioenergy with carbon capture and storage, or BECCS. The panel recommended several billion dollars be directed to research on NETs. Such technologies, it suggested, ought to be viewed as a “component of the mitigation portfolio,” rather than as a futuristic, last-ditch effort to reduce atmospheric CO2.



Stephen Pacala, a professor of ecology and evolutionary biology at Princeton University, chaired the panel. In an interview with Yale Environment 360, he talks about why NETs are needed, what should be done to advance them, and why he believes that “direct air capture” technologies could come into widespread use within the next decade.

Yale Environment 360: A couple of years ago, negative emissions weren’t much a subject of discussion, except maybe if you were in the inner world of the IPCC. Now, we’re hearing a lot about them. What has changed?

Stephen Pacala: I think there are three reasons. The first is: humanity keeps procrastinating on mitigation and so it becomes impossible at some point to meet the safe or declared target of limiting temperature increases to 1.5 to 2 degrees [Celsius] without negative emissions. That’s sadly where we are now. To meet the Paris Agreement targets, we need on the order of 10 billion metric tons of negative emissions — 20 percent of today’s annual emissions — by approximately mid-century, and 20 billion tons by century’s end. That’s a lot.

A second reason is that there is renewed interest, in some circles, about land-use options [to reduce CO2 emissions]. In the United States and a few other countries, there is interest in philanthropic foundations in land-use options [such as reforestation and no-till agriculture] that are ready to deliver negative emissions right now. The third reason is that there has been progress in the technical community in industrial versions of negative emissions technologies.

e360: We just saw in the [October 8] IPCC special report on holding temperature increases to 1.5 degrees that all of those pathways contain, to one degree or another, negative emissions. Meanwhile, your report suggests there’s not that much actual work going on right now in this field, that we have a huge research agenda even to determine what’s in the realm of the physically possible. So there seems to be a pretty big disconnect here.

Pacala: Why aren’t we doing more on negative emissions? It’s the same reason that we aren’t doing more of deliberate mitigation. The price on carbon is inadequate, and our decision to solve the problem hasn’t become sufficiently firm yet. As the IPCC’s 1.5-degree report claims, humanity is procrastinating – we have to do a lot more, a lot sooner…

Read the whole article here.

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