At the COP28 climate talks underway in Dubai, draft selections to date have referred to the abatement of carbon emissions utilizing carbon seize and storage (CCS) and carbon-dioxide removing (CDR) applied sciences. Considering the that means of the phrase ‘abatement’ has develop into an essential bone of competition, understanding the that means and limitations of CCS is essential – as additionally these of CDR.
What are CCS and CDR?
CCS refers to applied sciences that may seize carbon dioxide (CO₂) at a supply of emissions earlier than it’s launched into the environment. These sources embrace the fossil gas trade (the place coal, oil and gasoline are combusted to generate energy) and industrial processes like metal and cement manufacturing.
CDR takes the types of each pure means like afforestation or reforestation and applied sciences like direct air seize, the place machines mimic bushes by absorbing CO₂ from their environment and storing it underground.
There are additionally extra complicated CDR applied sciences like enhanced rock weathering, the place rocks are damaged down chemically; the ensuing rock particles can take away CO₂ from the environment. Other applied sciences like bioenergy with carbon seize and storage (BECCS) seize and retailer CO₂ utilizing biomass, like wooden.
At COP28, the time period “unabated fossil fuels” has come to imply the combustion of these fuels with out utilizing CCS applied sciences to seize their emissions. Draft choice texts level to a have to “phase out” such unabated fossil fuels. On the opposite hand, removing applied sciences have been referenced within the context of the necessity to scale zero and low-emission applied sciences and help forest restoration as a method to advertise emission removals.
How properly do CCS and CDR have to work?
While their technical particulars are clear, scientists have questions concerning the scale at which CCS and CDR are anticipated to succeed.
The Sixth Assessment Report (AR6), ready by the United Nations Intergovernmental Panel on Climate Change (IPCC), offers with climate mitigation. It depends quite a bit on the use of CDR for its projections associated to the world attaining the objective of limiting the world’s common floor temperature enhance to 1.5 levels C with no or restricted overshoot. (Overshoot means the temperature restrict is quickly exceeded.)
The emission eventualities that the IPCC has assessed which have greater than a 50% probability of limiting warming to 1.5 levels C (with no or restricted overshoot) assume the world can sequester 5 billion tonnes of CO₂ by 2040. This is greater than India emits at the moment yearly.
There isn’t any pathway to 1.5 levels C in AR6 that doesn’t use CDR.
“Without CDR, we would have to decrease emissions by more than during the COVID-19 pandemic annually,” David Ho, a climate scientist on the University of Hawaii, instructed this reporter.
“If CO₂ emissions continue at current levels, we will have a 50% chance of exceeding 1.5 degrees C compared to pre-industrial levels in seven years,” Dr. Ho added. “To achieve the decrease in CO₂ emissions we need by direct mitigation would be nearly impossible at this point, and would require a lot of CDR,” Dr. Ho defined.
Direct mitigation refers to decreasing our reliance on fossil fuels with renewable power sources like photo voltaic and wind energy.
How properly does CCS work?
The IPCC AR6 report states CDR ought for use “to counterbalance hard-to-abate residual emissions.” The cause: “available CDR is to be used strategically to compensate hard to abate residual emissions, not to maintain a high level of fossil fuel use,” Alaa Al Khourdajie, a analysis fellow at Imperial College London and a contributing creator to AR6, stated.
For CCS, too, Dr. Al Khourdajie and different AR6 authors confirmed in a latest paper that the time period “abated fossil fuels” needs to be used solely within the context of extremely efficient CCS purposes, with a seize fee of 90-95% or extra and the captured emissions being saved completely, amongst different situations.
But in the true world, pure CDR has been tacked on to current emissions. For instance, the 2023 ‘Land Gap’ report estimated that varied governments have proposed to take away CO₂ utilizing round one billion hectares of land. Based on this, the report mirrored: “Some pledges over-rely on land-based CDR to offset fossil fuel emissions. This raises serious concerns that these countries are shifting their mitigation burden away from reducing fossil fuel use.”
As for CCS developments, Henri Waisman, who leads a world initiative referred to as ‘Deep Decarbonization Pathways’ and coauthored an IPCC Special Report, stated, “CCS is still a technology under development without demonstrated feasibility at large scale despite decades of development.”
Aside from excessive value, he pointed to creation of extra power wants, and challenges within the transport and long-term storage of carbon.
How properly does CDR work?
CDR strategies like afforestation, reforestation, BECCS, and direct air seize are constrained by their want for land.
Land additionally invokes fairness issues. Land within the Global South is commonly thought of to be ‘viable’ and/or ‘cost-effective’ for planting bushes and deploying different large-scale CDR strategies. As a consequence, such CDR initiatives can adversely have an effect on land rights of indigenous communities and biodiversity and compete with different types of land-use, like agriculture that’s essential for guaranteeing meals safety.
This is of explicit concern vis-à-vis technological CDR at scale. “For example, what’s to prevent companies from using land in the global south for direct air capture and using land that would otherwise be used to generate renewable energy to power the economies of global south countries?” Dr. Ho requested.
He added that “the next decade will be pivotal in determining if there are viable and scalable CDR methods. But we also need to figure out who will pay for CDR at scale in the future.
“Imagine global north countries asking ‘why should we spend trillions of dollars on CDR when we can spend it on adaptation?’”
What are different pitfalls of CCS and CDR?
By eradicating CO₂ from their environs, there are issues that CCS and CDR create extra ‘room’ to emit the greenhouse gasoline. (In some instances, CCS has additionally been used to inject captured CO₂ is into oil fields to extract extra oil.)
In future emissions eventualities that the IPCC has assessed, the world’s use of coal, oil, and gasoline in 2050 wants to say no by about 95%, 60%, and 45% respectively (all median values) from their use in 2019 to maintain the planet from warming by lower than 1.5 levels C with no or restricted overshoot. But with out CCS, the anticipated reductions are 100%, 60%, and 70% for coal, oil, and gasoline by 2050.
In a latest paper, a global group of researchers wrote that larger use of CCS and CDR make manner for emissions pathways with the next contribution from gasoline.
Rishika Pardikar is a contract setting reporter.
