Widespread deployment of technology that sucks CO2 out of the atmosphere will require lots of cross-border cooperation and complex judgements about nations' varying responsibilities, a new peer-reviewed paper concludes.
The big picture: "Building the global partnership needed for an efficient [carbon dioxide removal] CDR solution will not be easy owing to technical, political, regulatory, accounting and social acceptability challenges. However, potential mutual benefits are large," an analysis in Nature Climate Change states.
Why it matters: Holding global warming greatly in check will demand various methods such as bioenergy with carbon capture, direct air capture machines, and large-scale forestation, the paper notes.
- It points to a late 2018 UN scientific review that found holding temperature rise to 1.5 °C — the most ambitious goal of the Paris Agreement — means removing CO2, not just slowing and stopping new emissions.
- "[T]he most plausible and realistic pathways to meet our ambitious climate goals may be through strengthening CDR cooperative actions," it notes.
What they did: The paper considers technical constraints — including nations' differing "biophysical limits" — and broader questions around equity and responsibility to enable the scale-up of CDR.
They created a global model for assigning nations CO2 removal "quotas" under "responsibility, capability and equality" principles.
- Responsibility is linked to a nation's historical emissions.
- Capability addresses financial resources and "implies wealthier countries are assigned a greater share" of CDR efforts.
- Equality, meanwhile, is more tethered to population.
What they found: The allocation for different regions, and even nations within those regions, varies — sometimes vastly — depending on which of those frameworks you apply.
- OECD countries would have 38% of the cumulative quotas by 2100 under the "responsibility" filter, 54% under "capability," but only 11% based on "equality."
- By 2100 Asia (including India) would have 7% under the "capability" filter, but 43% under the "equality" method of cumulative allotment.
- The United States' quota is roughly twice as high under "responsibility" as it is under "capability."
What they're saying: "We were not aware of a similar analysis and we hope that it can open a necessary conversation on these difficult questions of equity and responsibility," co-author David Reiner, who's with the Energy Policy Research Group at the University of Cambridge, tells me.
- He says, referring to the different filters applied, that there's no "right answer," and that the study is intended as a first step.
What's next: "One of the main takeaways from this preliminary analysis is that cooperation will be critical for successful deployment of CDR and so we are keen to further extend our analysis by exploring different mechanisms for cooperation," Reiner said.