- Carbon Dioxide Removal techniques are gaining visibility in the global discourse, including in the recently concluded COP30, but are widely considered speculative technologies that are unproven at scale.
- After Carbon Capture, Utilisation, and Storage (CCUS) technologies, the new player in town is Direct Air Carbon Capture (and Storage).
- Critics have pointed out that Carbon Dioxide Removal technologies deviate from the real problem: reducing emissions.
The 30th Conference of the Parties (COP30) concluded, and, as in years past, frantic negotiations took place over the path to mitigating the effects of climate change. COP30 marked the 10th anniversary of the Paris Agreement of 2015, in which world leaders set the goal of limiting average global temperature rise to well below 2°C and striving for 1.5°C. The Emissions Gap Report 2025, released before COP30, noted that global emissions will most likely rise above 1.5°C in the next decade, and limiting the rise to 2°C will require rapid reductions.
A review of recent IPCC assessments — including the AR6 Working Group III report, which evaluates mitigation strategies, and the Special Report on Global Warming of 1.5°C, which examines the consequences of exceeding the 1.5°C limit — indicates that pathways to limit warming to 1.5°C now universally depend on the large-scale deployment of carbon dioxide removal (CDR). CDR is now increasingly being featured in climate negotiations, most notably at COP30, where industrial CDR entered the official agenda as part of the strategic objective to accelerate zero and low emission technologies in hard-to-abate sectors. It also gained dedicated spaces for advocacy and coordination. However, it did not enter the final COP30 negotiated text.
While CDR is gaining visibility in global climate discussions, such discourses risk reliance on speculative technologies that are unproven at scale and may delay climate action.
What are carbon dioxide removal technologies?
Scientists and modelling experts have stated that to limit global temperature increases to the target, we must not only reduce carbon dioxide emissions but also remove them from the atmosphere.
In theory, carbon dioxide removal (CDR) technologies are designed to extract carbon dioxide from the atmosphere and store it safely in geological, biological, or oceanic reservoirs for hundreds to thousands of years to help limit global temperature increases, at least in principle.
In practice, however, CDR deployment faces major challenges. The Emissions Gap Report 2025 says limiting warming to 1.5°C is now largely out of reach. To stay on that path, global emissions would need to fall by about 55% below current levels by 2035, far beyond what countries have pledged in their Nationally Determined Contributions (NDCs), which are each country’s self-defined climate action plans under the Paris Agreement.
To be effective, CDR technologies must meet three key criteria. One, they need to remove more carbon dioxide than they themselves emit. Two, they need to permanently remove and store CO₂ rather than have it return to the atmosphere in a few years or decades. Three, the cost of implementing it has to be low for the scale of implementation that’s needed. At present, the technologies are not proven to be implementable across industries worldwide.
Among proposed CDR methods, some use nature’s own elements, some require extensive engineering. Traditional CDR enhances natural carbon sinks, such as forests and soils, while novel CDR uses engineered solutions that aim to capture and store CO₂ more permanently and at far greater scales than nature typically allows.
However, each comes with their challenges. Natural solutions like afforestation and reforestation may be easier to implement, but in the face of natural disasters, they are less durable. On the other hand, novel approaches promise more durable storage but require extensive infrastructure and remain costly and untested at scale.
Can new technologies remove carbon dioxide at scale?
Fossil fuels still account for over 80% of the global energy mix. While we depend on them for energy, “the problem really is the carbon dioxide emitted from the fossil fuels,” said Vikram Vishal, professor in the Department of Earth Sciences, Indian Institute of Technology-Bombay, and co-founder of Mumbai-based startup UrjanovaC, which has patented a novel Carbon Capture, Utilisation, and Storage (CCUS) method. So, he argued, in addition to reducing emissions in intensive sectors like steel, power, cement, etc., historically emitted carbon dioxide needs to be captured.
Among technologies being tested for this purpose is Direct Air Carbon Capture and Storage (DACCS), which captures historically emitted carbon dioxide directly from the air. Large fans draw in air into a filter that contains materials that can absorb carbon dioxide. Chemical processes trigger the absorption while the rest of the air is released back into the atmosphere — separating carbon dioxide into the absorbing material. The filters are then heated, releasing the carbon dioxide molecules, which are compressed and transported underground, to geological storage facilities, for long-term storage. So, in theory, it is a carbon-negative technology as it can capture and store historical emissions, unlike some of the other technologies that fall under CCUS which limit future emissions.
According to the State of Carbon Dioxide Removal report published in 2024, CDR projects, natural and engineered, dominate the Global North, especially in North America, driven by the sizable presence of forest management projects in Mexico and the U.S. China and India also show notable progress.
However, DACCS has been adopted the least among the newer carbon dioxide removal technologies. It is at a relatively early stage of development compared to many other climate change mitigation and carbon management technologies and its high cost is one of the major barriers in implementation. The cost of removing one ton of carbon dioxide can reach $1,000, said Vishal, making it one of the most expensive CDR options. It also needs large quantities of fresh water and energy inputs, which must come from renewable sources.
In addition to technological bottlenecks, economic and policy requirements also limit the ability to scale up the technology quickly to meet capture demands. That is why UrjanovaC deploys a combination of CCUS and DACCS technologies. The difference boils down to the source of the CO2. If the source is flue gas and other gas emissions from a power plant or a cement factory, the technology becomes CCUS. “We need policy support to be able to scale up these technologies,” said Vishal about future possibilities. In 2024, the government of India initiated discussions to assess ways to reduce future emissions with market support.
Realistically, how effective are carbon removal technologies?
Critics have challenged the mitigation efficiency of new CDR technologies, including DACCS.
For example, Climeworks, the first company to implement DACCS, captures carbon using large machines located in Iceland, but has been unable to capture enough carbon to offset even its own operation emissions. Project STRATOS, touted as the world’s largest carbon capture project, has also been criticised for promising more capture than demonstrated.
Additionally, critics have pointed out that CDR technologies deviate from the real problem: reducing emissions. “In our model scenarios, we find that planning for high CDR as part of a least-cost approach to meeting climate policy goals, results in delayed emissions reductions,” said Matilyn Bindl from the University of Wisconsin-Madison, who was the co-author of a 2024 study exploring optimal ways to reach the Paris Agreement objectives. That is, “it is possible that companies may delay their emissions reductions in the presence of CDR,” she added.
The researchers found that the optimal scenario for policymakers to meet the goals of the Paris Agreement would be, starting in 2025, to sharpen emissions reductions, and, if CDR technologies scale up substantially by 2050, to adopt high CDR rates till 2100 while continuing conventional reductions. “Given that some amount of CDR will be necessary in the future to meet climate goals, our paper advocates for robust policies that support early investment in CDR while also prioritising ambitious emissions reductions,” said Matilyn.
Another criticism of such technologies is the pre-selling of future carbon credits in voluntary markets. This means that if companies eventually capture carbon dioxide from the atmosphere, other net-emitting companies can pay the carbon capturing companies — buy carbon credits — to claim to meet their own reduction targets. Pre-selling means the payment is already done for yet-to-be-implemented carbon dioxide capture.
This kind of trade-off also allows industrialised and developed nations of the Global North pass the buck for their emissions cheaply to the Global South.
Recently, UrjanovaC announced purchase agreements of carbon credits with companies and programmes based in the Global North. Each credit amounts to one ton of historically emitted carbon dioxide removed from the atmosphere. UrjanovaC’s carbon credits will be delivered over the next two years, clarified Vishal.
According to an estimate, the direct air capture market in India is likely to grow significantly in the coming years, during the same period in which global emissions must fall drastically to avoid escalating disasters. As a result, the fundamental question remains: does pushing the buck to the emerging carbon markets distract from the real discourse?
Are carbon removal schemes trustworthy or are they just shifting responsibility?
In optimistic future scenarios in the IPCC reports, in which global warming returns to 1.5°C, climate models assume vast amounts of carbon dioxide removal will occur in developing countries. Across scenarios, 65-84% of projected carbon sequestration before net-zero in the most ambitious pathways, and 60-85% even in 2°C pathways, is expected to occur in the Global South.
But, as scholars from the Global South have pointed out, the problem lies in the models themselves and the numbers they rely on. All the scenarios, numbers, and estimates rely on assumptions that do not follow the principles of equity, pushing the burden of climate mitigation onto developing nations, where developmental priorities like food security, increased energy access, and poverty eradication take precedence over diverting focus to speculative CDR technologies.
So, the world cannot afford to over-rely on future removals to delay emission reductions, definitely not at the cost of globally equitable carbon mitigation.
Achyut Mishra, professor in the department of Earth Sciences at the Indian Institute of Technology-Gandhinagar, said that, in addition to the high costs of novel CDR technologies, they require significant research to be deployed at scale on the ground. So the focus should remain on industrial decarbonisation. At the same time, he hopes that a formalised carbon market helps the transition from a fossil-fuel-powered to a low-carbon economy, as companies might see decarbonisation as a business model.
As companies in India foray into novel CDR technologies, several questions remain about whether these technologies are reliable, feasible, necessary, scalable, and equitable. At the heart of climate action lies buzzwords, but a lack of clear direction, regulations, and policy.
Read more: Carbon markets fund plantations and livelihoods
Banner image: Burning of garbage releases thick smoke in a city. Image by Jaskaran Singh via Wikimedia Commons (CC BY-SA 4.0).
