Does extracting CO2 from the atmosphere offer a potential fix for climate change?

Scientific advancement [or] Research discoveries - Capturing Carbon Dioxide: Could This Be the Answer to Climate Change?

The increase in carbon dioxide (CO2) emissions is still an ongoing issue. Although numerous nations have been attempting to withdraw greenhouse gases from the atmosphere, a significant report states that these efforts are insufficient for effective climate protection. The reduction of CO2 emissions is still the key to climate preservation, according to a team led by the first author, Stephen Smith, from the University of Oxford.

However, the removal of CO2 and storage must increase up to 7-9 billion tons per year by mid-century, as per the report, in order to limit global warming as per the Paris agreement, either significantly below two degrees or up to 1.5 degrees.

The German government has recently approved a draft law for CO2 storage, focusing primarily on the North Sea. Initially, this will involve emissions stemming from industries like lime and cement and waste incineration.

Modern techniques for CO2 removal, such as filters, are still in their infancy. These methods have so far managed to remove only 1.3 million tons of CO2 annually, which is less than 0.1% of the total extracted.

"We're at the stage where we were with renewable energy 30 years ago," said Daniela Thrän from the Helmholtz Center for Environmental Research (UFZ) in Leipzig. "We need to consider how to introduce these new, cutting-edge solutions into the market now." The establishment of demonstration plants, as the US has already done, and the selection of CO2 storage sites are essential steps in this process.

Some other modern techniques include:

Biochar: Plant residues are heated and used as a carbon-rich substrate in the soil, which breaks down very slowly.
Enhanced weathering of rocks: Many rocks absorb CO2 during weathering. Crushing these rocks can create more surface area for absorption.
Capture and storage of CO2 (DACCS): Large machines extract CO2 from the air and store it underground.
Bioenergy with CO2 capture and storage (BECCS): Plants absorb considerable amounts of CO2 while growing. Once burned, the resulting CO2 is also stored.

An interesting project is the "Mammoth" (Mammut) plant of the Zurich company Climeworks, which was established in Iceland in 2024. The plant's capacity is 0.036 million tons of CO2 absorption per year, almost nine times greater than the largest plant of the same company.

Yet, energy is needed for the construction and operation of this plant. "The plant was constructed in Iceland because a great deal of renewable energy is available there," said Thrän. For countries like Germany, these methods would only be feasible if adequate green energy is available.

There are limited options for Germany in the near term due to the absence of a CO2 infrastructure and demonstration facilities. These include afforestation, soil enrichment with carbon-rich material like biochar, or maintaining a year-round cover over the soil. Additionally, the feasibility of CO2 absorption within the framework of peatland rewetting is questionable.

The gap between national CO2 removal proposals of countries and compatible scenarios with the Paris temperature target remains significant. The actual size of the gap remains unclear.

"A major uncertainty is how to account for the fact that global emissions have not decreased as predicted in the scenarios lately," said Oliver Geden from the Stiftung Wissenschaft und Politik in Berlin, who was also involved in the report. This may suggest that the gap is significantly larger than initially estimated.

Global CO2 emissions reached a record high of 40.9 billion tons in 2023 when methane and nitrous oxide emissions are also included, resulting in a complete climate impact of about 55 billion tons of CO2. Methods for removing methane and nitrous oxide are still in earlier stages of development. Removing these gases is difficult due to their low concentrations in the atmosphere.

The report admits a flaw in its data, as it doesn't factor in the possibility of certain activities proving to be short-lived, such as those affected by unexpected disruptions or mismanagement.

Preserving CO2 storage areas like forests will pose a considerable challenge. The increasing effects of climate change such as altered precipitation patterns, forest fires, and the spread of bark beetles may increase the gap between the necessary CO2 removal levels.

The growth of CO2 removal technologies is difficult to predict. What's most critical is the upcoming round of national climate protection contributions submitted by countries in 2025, as these will provide insight into their proposed measures for the period up to 2035. ("Status of CO2 Removal 2024" report.)

The report highlights a flaw in its numbers: The potential ineffectiveness of certain activities, such as those disrupted due to unforeseen events or poor management, is not taken into consideration.

The report suggests that the preservation of CO2 storage, such as forests, will present a significant obstacle. The impacts of climate change, including shifts in rainfall patterns, forest fires, and the bark beetle infestation, may lengthen the timeline for reaching the necessary CO2 removal levels.

The development of CO2 removal technologies is difficult to foresee. Crucially, we must anticipate the next round of national climate protection contributions from countries due by 2025. (Paraphrasing the second to last paragraph from the given text.)

Simon Wolf, representing Germanwatch, commends the report for clearly stating the crucial message upfront: "Reducing emissions is key to fighting global warming, and current efforts aren't nearly enough." According to Wolf, it's imperative to achieve negative emissions quickly to align with a 1.5-degree path.

To prioritize, he stresses the significance of focusing on maintaining forests, peatlands, and marine ecosystems before concentrating on technical solutions. The multiple benefits these efforts provide make them more advantageous.