April 13, 2024

Carbon dioxide removal: can it be effective?

Carbon dioxide pollution in the atmosphere reached an all-time high last year – 424 parts per million. This is probably the highest level since three million years ago, when trees grew in the polar regions and sea levels were up to twenty meters higher. However, scientists warn that unless the warming caused by the accumulation of carbon dioxide and other greenhouse gases is contained, the planet is heading towards a catastrophic increase in average global temperatures. This could affect ocean circulation, trigger a sustained rise in sea levels and destroy coral reefs.

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One climate solution that is attracting government and private sector attention is carbon dioxide removal, or CDR. The question remains whether it will work at the scale and time needed to avert climate calamity.

What is CDR?

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CDR includes technologies and processes that extract carbon from the atmosphere and then store it permanently in soil, vegetation, oceans or aquifers. CDR refers only to intentional human activity, including nature-based solutions such as planting trees where they don’t exist, restoring wetlands, and improving soil practices to absorb and store carbon. It also includes the removal of marine biomass and carbon, as well as mineralization-based processes that, for example, use crushed rocks to absorb carbon.

Other CDR practices rely on emerging technologies. They include techniques that extract carbon from the air with chemicals and giant fans to store it for thousands of years in deep underground geological formations, such as rocks with porous areas filled with salt water or depleted oil and gas reservoirs. These technologies are called Direct Air Capture (DAC). CDR can also involve carbon storage in commercial products such as wood panels and cement.

CDR approaches have trade-offs in terms of cost, effectiveness, risks, and timelines. DAC technologies have increasingly attracted investor attention, but they are the most expensive carbon removal technique and have not yet been proven on a large scale. Methods that rely on storage in geological formations last much longer than other forms of CDR, meaning carbon can remain locked up for thousands of years, while methods that rely on soils and vegetation are less expensive, although they can prove to be less durable. For example, when a forest fire incinerates a forest, the forest stops storing carbon. Storage in commercial products such as structural lumber used in construction [PDF] it can also be comparatively short-lived: when the building is destroyed, carbon risks being released.

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CDR is sometimes grouped with a related technology known as carbon capture utilization and storage (CCUS). CCUS is typically used to capture carbon emissions directly from pollution sources, such as factories or fossil fuel operations. While CCUS can reduce the amount of greenhouse gases reaching the atmosphere, it does not reduce the gases that are already in the atmosphere. Therefore, CCUS does not act to reduce temperatures; in contrast, the CDR does.

Why is CDR necessary?

Through the UN climate negotiation process, nations have set a goal of limiting global average surface temperatures to ideally no more than 1.5° Celsius (2.7° Fahrenheit) above pre-industrial times. Achieving the 1.5° target requires nations to achieve net-zero emissions by 2050, which is only possible through large amounts of CDR as well as aggressive efforts to reduce the amount of carbon reaching the atmosphere, according to the Intergovernmental Panel on Climate Change (IPCC). Scientists estimate that by 2050, the world may need to rely on CDR to remove up to ten billion tons of carbon – twice the annual emissions of the United States – every year.

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The IPCC predicts that, by 2050, the CDR can reduce the accumulation of emissions in the atmosphere, thus slowing warming; The CDR would also have to remove more carbon from the atmosphere than is added to it to reach the net-zero emissions goal. After 2050, CDR could further offset emissions from “hard to reduce” sectors such as the steel industry, aviation, shipping and agriculture, and create net negative emissions by removing carbon that has already accumulated from the atmosphere. .

Who is financing this?

The need for CDR has sparked interest in both the private sector and governments. Last fall, at the UN Conference of the Parties (COP28) in Dubai – the latest UN climate meeting – more than seventy sessions focused on carbon removal, an exponential increase over previous years.

Money has started flowing into CDR initiatives and Washington is a government that is betting heavily on carbon dioxide removal. The bipartisan infrastructure law passed in 2021 provides $3.5 billion for the creation of four regional CAD centers, while the Inflation Reduction Act passed in 2022 creates tax benefits worth a credit of up to $180 per tonne for CDR and carbon storage. It could also lead to increased employment across the country: A new study from the Rhodium Group finds that nearly every state has the potential to host at least one DAC facility by 2035. By 2050, the economic benefits could flow to every state , with Texas as the biggest winner.

Other governments are also investing in CDR. Australia, Canada, Japan and the United Kingdom have also provided research and development funding for CDR, and the European Commission has proposed a strategy for the European Union (EU) to capture, trade and store carbon in a sustainable way to meet the objectives EU climate change. In February, the EU moved closer to adopting a framework to certify the quality of carbon dioxide removal projects. The effort could increase confidence in the quality of carbon credits traded on carbon markets.

In addition to government support, the private sector has recently been clamoring for carbon credits from CDR projects to meet corporate net-zero emissions commitments. The demand for carbon credits has driven investment in DAC by companies such as Microsoft, Shopify and Airbus; Swiss Air and Lufthansa have also partnered with a DAC start-up. Consulting firm McKinsey predicts that by 2050, the CDR industry could be worth up to $1.2 billion.

Why are there reservations about the CDR?

Advocates for rapidly phasing out fossil fuels have expressed concern that CDR efforts could create a moral hazard by undercutting the ambition to reduce oil and gas consumption. Occidental Petroleum chief Vicki Hollub lent credence to this argument when she suggested that implementing the DAC would preserve the oil industry and give oil producers a license to continue operating. Occidental plans to build about 100 DAC plants to help its oil production reach net zero.

Concern also arose that companies and governments could expand the applications of CDR beyond addressing emissions from hard-to-abate sectors. The IPCC has warned that CDR should not replace [PDF] for sharp reductions in carbon emissions, emphasizing that reducing the amount of carbon produced and emitted is the main way to keep warming to 1.5°C. It predicted a lesser role for large-scale CDR technology such as DAC, given that the success of the technology at scale remains to be seen, making dependence on it a “major risk”. The International Energy Agency has also recognized the need for CDR, but warned against relying too heavily on technologies that are “expensive and unproven.”

Critics argue that CDR is too expensive and energy-intensive to serve as a viable alternative to rapidly phasing out fossil fuels. The world’s first large-scale DAC facility, located in Iceland, can only capture around four thousand tons of carbon annually, a tiny share of global emissions. There are also many questions about whether CDR technology can be scaled quickly enough and at a cheap enough price to avoid significant warming. Some argue that CDR money would be better spent keeping more emissions out of the atmosphere in the first place, for example by increasing investment in renewable energy such as solar and wind.

Finally, the focus on carbon removal does not address other greenhouse gas emissions, such as methane, that cause more warming in the immediate future. A methane molecule could last only twelve years in the atmosphere, while a carbon molecule could last hundreds of years. But during its short lifetime, the methane molecule could retain eighty times more heat compared to the carbon molecule. Atmospheric methane levels are already two and a half times higher than in pre-industrial times and, in recent years, methane emissions have accelerated.

Is the CDR on the right track?

A series of steps known as measurement, reporting and verification (MRV) are essential to ensure that CDR is used responsibly. The European Union has taken the lead in creating standards, seeking to bring clarity to the quality of CDR initiatives. In contrast, the United States has not yet adopted a national regulatory framework, although it is a world leader in legislation to support the CDR. Without greater clarity regarding the effectiveness of CDR projects, “greenwashing” could occur.

Elections around the world could play an outsized role in future CDR investments. Former president and 2024 candidate Donald Trump has pledged to dismantle the Reducing Inflation Act, which gave an unprecedented boost to CDR investments. Similarly, in Europe, the growing influence of right-wing politicians could threaten government support for the CDR. Given the expense involved and the uncertainty of success, some CDR efforts, including engineered DAC solutions, could fall by the wayside without government support.

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