Pros and cons of carbon dioxide removal | Experts’ Opinions

Carbon Dioxide Removal (CDR) is considered to be an urgent priority together with efforts to rapidly reduce GHG emissions, to stop climate change and meet the temperature goal of the Paris Agreement. CDR involves capturing CO2 from the Earth’s atmosphere and storing this either on land, in the ocean, in geological formations or in products. The most well-known examples of CDR include reforestation, biochar, Bioenergy with Carbon Capture and Storage (BECCS) and Direct Air Carbon Capture and Storage (DACCS).

The latest reports reveal a “large gap” in the level of CDR needed. Only recently, Denmark inaugurated a carbon dioxide storage facility – the first in the world to store CO2 imported from abroad – which was established in the North Sea at a depth of 1,800 meters and considered to be an essential tool for slowing the process of global climate warming. But are CDR and other similar methods good practices? Let’s check what the experts have to say about this.

DevelopmentAid:  What are some of the pros and cons of Carbon Dioxide Removal, including direct air carbon capture and storage (DACCS)?

“Climate change is an existential threat to our planet and its inhabitants. Scientists and environmentalists have turned to CDR technologies in the quest for a solution. CDR can reverse the damage by extracting CO2 from the air and storing it. This technology has various methods, including direct air capture (DAC), soil carbon sequestration, biomass carbon removal and storage, enhanced mineralization, ocean-based CDR, and planting trees. However, not all CDR methods are created equal. While some have the added benefits of promoting wildlife, soil, water, and food production, others are expensive, energy-intensive, unproven, and risky. Some methods may even negatively impact biodiversity or compete with other land uses. It is important to remember that CDR is not a replacement for reducing emissions through renewable energy sources but rather a complementary measure. If emissions continue to rise, CDR may become necessary to mitigate the impacts of climate change. Nonetheless, it is crucial to recognize that CDR is not a silver bullet or a permanent solution but rather a temporary measure that buys us time to change our ways. Ultimately, it is up to society to decide whether to pursue CDR or focus on alternative ways to fight climate change.”

“Pros of CDR:

• CDR contributes significantly to the reduction of nitrogen oxide (NOx) and sulfur dioxide emissions produced by oxy-fuel burning.
• Smallholder farmers might benefit from increased income from biomass production as a result of afforestation/reforestation and harvesting.
• CDR can decrease the length of time we spend over the 1.5 °C global warming level and hence limit the climate impact to vulnerable communities.
• Focused programs of afforestation/reforestation can help to slow or halt desertification/ land degradation. Afforestation/reforestation can mitigate the effects of extreme weather events by slowing winds and preventing floods and erosion.
• Wetland restoration, which involves reestablishing wetland hydrology and reintroducing native vegetation in freshwater and coastal wetlands, provides significant benefits in terms of clean water, fisheries productivity, flood protection for urban and rural communities, aquatic and land ecosystem protection, improved air quality, and CO2-removal.

Cons of CDR:

• One of the major drawbacks of removing CO2 from the air through technologies such as direct air capture is that the gas concentration in the atmosphere is relatively low.
• CDR technology is more expensive and there are currently no regulatory drivers in most countries to incentivize or compel the application of CDR.
• Afforestation/reforestation in marginal, ecologically fragile arid and semi-arid areas, Ramsar sites and other wetlands would endanger their survival and have a significant impact on local geographical, socio-economic, cultural and livelihood interdependencies. Changes in land vegetation can cause local precipitation and temperature to fluctuate in opposing directions.
• Afforestation/reforestation can induce land-use displacement (e.g., croplands) or indirectly trigger deforestation elsewhere. Poorly executed interventions can result in indigenous communities’ displacement, isolation from ecosystem services, biodiversity loss and land degradation.
• Long-term, CDR offers a substantial and complex public policy challenge since many countries are yet to include this into their mitigation policy instruments (including regarding forestry, land-use change, industries, carbon pricing, and carbon markets).
• CDR may underperform expectations owing to projection uncertainties, unacceptable consequences, or unanticipated reversals while land-use change may result in increasing GHG emissions and pose a threat to food security. There is a danger of altering nutrient cycles and causing soil degradation which can lead to higher carbon emissions.
• Moreover, long-term CO2 storage capacity is uncertain and CO2 transport and storage sites may pose a potential threat of contaminating both the soil and groundwater in the area surrounding the storage site.
• The public may object to such projects being erected near them due to perceived health and lifestyle threats.

Conclusion:

Assessments of the impacts of CDR should become clearer in terms of their empirical base and should progressively include pilot activity experiences as they emerge. Countries may learn from one another as their experiences accumulate, and with increasingly precise bottom-up potential estimates, uncertainty around global CDR potentials would eventually be minimized. It is vital that policy planning and governance for both emission reductions and CDR should not overburden one goal above all others. Specific consequences may only be assessed in the context of unique local circumstances, considering economic and social structures, the rule of law and institutional quality, local or regional governance, and environmental factors.”

“CDR methods, such as Direct Air Carbon Capture and Storage have been a hot topic in the past few years. Here are a few high-level ideas to shed some light on the pros and cons of adopting a CDR method such as DACCS:

• CDR technologies lower and remove carbon dioxide emissions from the environment, which contributes to lowering the level of greenhouse gases that directly impacts climate change. There is no doubt that such methodologies can aid in reducing the effects of global warming on the environment and public health as well as its severity.
• Another advantage is that a hybrid approach could be adopted where CDR technologies can be used in conjunction with other ways to reduce greenhouse gas emissions, such as renewable energy and energy efficiency initiatives. They are complementary to other mitigation options. This may offer a more thorough and efficient plan for reducing climate change.
• DACCS initiatives/technologies such as the usage of chemical reactions to capture CO2 from the air and convert it into a concentrated stream of CO2 to be stored or used in other applications, or the usage of modular fan-driven machines to capture and store CO2 underground can be adopted to accelerate CDR but at the burden of cost and energy consumption.
• As a Con to adopting to CDR, a catalytic CDR method such as DACCS is the diversion it creates from reducing greenhouse gas emissions at source and taking specific measures in waiving carbon emissions by adopting green solutions.

“Pros:

• Contributing towards reducing the pace of global warming: CDR technologies can help to reduce the amount of carbon dioxide in the atmosphere, slow down global warming, and mitigate the impacts of climate change.
• It can be used in conjunction with other climate solutions such as renewable energy and energy efficiency to achieve greater carbon reduction.
• Potentially it can create new economic opportunities in areas such as carbon capture and storage, mineralization, and ocean fertilization.
• Smog reduction and improved air quality – by reducing the amount of carbon dioxide and other pollutants in the atmosphere, this can substantially contribute to reducing costs to the health sector.
• Co-benefits: Some CDR technologies, such as afforestation and reforestation, can provide co-benefits such as habitat restoration, biodiversity conservation and improved ecosystem services.

Cons:

• Cost and energy-intensive: CDR technologies can be expensive and a large amount of energy is utilized to develop and implement these which may limit its adoption and scalability.
• Potential negative impacts on ecosystems: Some CDR technologies, such as ocean fertilization, may have negative impacts on marine ecosystems, and land-based methods may compete with other land uses such as food production. The technology assumes CDR is based on certain natural phenomena however the long-term impacts have not been validated.
• Justify the use of fossil fuel: Such technologies can be used to justify continued fossil fuel use by assuming that captured carbon dioxide can be stored indefinitely which is not necessarily the case.”

“We are ignoring the “elephant in the room” by debating if carbon dioxide removal (CDR) is required, or if one kind of CDR is better than another. This is because we need an overhaul of climate policy to adequately support emissions reductions and CDR. A critical issue is that we will need at least 5-10 GtCO₂ per year of total CDR by 2050, and double that rate by 2100. This amount of CDR will be needed because of residual emissions. But existing carbon markets are not structured for supporting this amount of CDR.

First, consider that the annual cost of 10 GtCO₂ per year of CDR could be roughly US $1 trillion (assuming $100 per tCO₂). This cost will likely exceed the generosity of governments due to fiscal pressures, and it will exceed demand for carbon credits in the private sector. Moreover, carbon offsetting cannot be used to fund this much CDR because gross emissions need to be reduced. Offsetting should only be used in situations where there is no alternative.

Second, consider that there are biophysical and social constraints on reforestation and afforestation as a “natural” method of CDR. Natural land-based methods are important, but they may need to be capped at roughly 5 GtCO₂ per year to avoid irresponsible practices. This implies that novel CDR technologies are also needed, and they need to be scaled-up quickly.

Third, consider that most trees are found in large forests; and that forests are characterized by carbon flows between plants, soil fungi, microorganisms, and animals. Carbon cycling and water cycling in forests actually establishes the climatic conditions that ecosystems depend on for their stability. Subsequently, large forest ecosystems cannot be regenerated if they are pushed into a different biophysical state. In other words, when forests are degraded by people or disrupted by climate change, they tend to release CO₂ irreversibly. This is already happening in the Amazonia.

In summary, when natural CDR is financed by carbon offsetting it creates a systemic risk. This is because:

1. offsetting tends to crowd-out other policy ideas;
2. a fraction of CDR will be reversed by future climate change;
3. offsetting encourages greenwashing and perpetuates the status quo;
4. offsetting depends on additionality claims that are prone to gaming.

Although these challenges are daunting, I propose that a new policy, called a “carbon reward”, can fund CDR and emission reductions at speed and scale.”

See also: Is the world’s 1.5-degree warming threshold slipping out of reach? | Experts’ Opinions

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