With the inauguration of the president Joe Biden, the United States returned to Paris Climate Agreement, which represents a huge step towards reducing emission of greenhouse gases. However, a special report by the Intergovernmental Panel on Climate Change (IPCC, in English) points out that the reduction alone will not be enough. The answer, however, may lie in the removal of CO₂ by a technology called Direct Air Capture, or DAC.

Research published in Nature detailed how the investment in an emergency program using CO₂ removers with this technology would be much more efficient as a measure to combat the climate crisis.

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However, the study reports that an initiative of this size would require an investment “equivalent to those made in times of war”, of around 2% of global GDP.

What is Direct Air Capture?

While the study presented by the researchers brings up-to-date and encouraging data on the effectiveness of Direct Air Capture in combating global warming, its use in removing CO₂ is nothing new. In 2020, companies like United Airlines e Microsoft disclosed investments in technology to offset their carbon emissions.

CO₂ collectors from Climeworks. Credit: Climeworks / Disclosure

DAC consists of using any mechanical system to capture carbon dioxide from the atmosphere. Plants, for example, use liquid solvents or solid adsorbents to separate CO₂ from other gases, while companies like Switzerland's Climeworks and Canada's Carbon Engineering use giant fans to "collect" the air and filters or chemical solutions to separate the gases .

The removed CO₂ is concentrated, purified and compressed. Subsequently, the component can be injected into the soil to assist in the Oil extraction, decreasing its viscosity. This procedure can help offset the gas emissions that result from the burning of oil.

According to The Economist,, it is estimated that the Direct Air Capture technology may reach a market value of US $ 100 billion by 2030.

Obstacles

Despite this market potential, money is precisely the main challenge to make DAC a reality, since other forms of CO₂ removal are not so expensive.

Luckily, technology tends to become cheaper over time, and the rise of the carbon market where negative emissions can be traded also contributes to its economic viability.

Energy consumption is also a problem for Direct Air Capture machines. Equipment with the technology could use up to a quarter of the global energy in 2100. To mitigate this “negative” aspect, new DAC methods that reduce consumption are being developed .

With The Conversation