The limitations of CCS and CDR and their grip on our future climate | Explained Premium
The Hindu
At COP28, CCS & CDR techs discussed to abate carbon emissions. CCS captures CO₂ from sources like fossil fuel industry & CDR uses natural means & techs like direct air capture. AR6 relies on CDR to limit warming to 1.5°C. CCS & CDR create room to emit, but use of coal, oil & gas must decline 95%, 60% & 45% by 2050. Concerns over land use & who pays for CDR at scale remain.
At the COP28 climate talks underway in Dubai, draft decisions thus far have referred to the abatement and removal of carbon emissions using carbon capture and storage (CCS) and carbon-dioxide removal (CDR) technologies. Considering the meaning of the word ‘abatement’ has become an important bone of contention, understanding the meaning and limitations of CCS is important – as also those of CDR.
CCS refers to technologies that can capture carbon dioxide (CO₂) at a source of emissions before it is released into the atmosphere. These sources include the fossil fuel industry (where coal, oil and gas are combusted to generate power) and industrial processes like steel and cement production.
CDR takes the forms of both natural means like afforestation or reforestation and technologies like direct air capture, where machines mimic trees by absorbing CO₂ from their surroundings and storing it underground.
There are also more complex CDR technologies like enhanced rock weathering, where rocks are broken down chemically; the resulting rock particles can remove CO₂ from the atmosphere. Other technologies like bioenergy with carbon capture and storage (BECCS) capture and store CO₂ using biomass, like wood.
At COP28, the term “unabated fossil fuels” has come to mean the combustion of these fuels without using CCS technologies to capture their emissions. Draft decision texts point to a need to “phase out” such unabated fossil fuels. On the other hand, removal technologies have been referenced in the context of the need to scale zero and low-emission technologies and support forest restoration as a means to promote emission removals.
While their technical details are clear, scientists have questions about the scale at which CCS and CDR are expected to succeed.
The Sixth Assessment Report (AR6), prepared by the United Nations Intergovernmental Panel on Climate Change (IPCC), deals with climate mitigation. It relies a lot on the use of CDR for its projections related to the world achieving the goal of limiting the world’s average surface temperature increase to 1.5 degrees C with no or limited overshoot. (Overshoot means the temperature limit is temporarily exceeded.)