What direct air capture actually does — and doesn't do
Direct air capture (DAC) is a technology that pulls CO₂ directly out of the ambient air. It is a form of climate mitigation — it reduces the total amount of CO₂ in the atmosphere — not a form of climate adaptation. Adaptation means helping people, especially vulnerable communities, cope with the effects of climate change that are already happening: building sea walls, developing drought-resistant crops, improving early warning systems for extreme weather. DAC does none of these things. It does not protect a coastal village from rising seas or a farmer from crop failure.
The most comprehensive policy analysis among these studies, based on 125 expert interviews, explicitly frames DAC as a tool for achieving net-zero emissions, not for addressing local vulnerabilities [3]. Another study models a wartime-like crash deployment of DAC and finds that even with massive investment (1.2–1.9% of global GDP annually), the world would still reach 2.4–2.5°C of warming by 2100 [5]. That level of warming would disproportionately harm the world's poorest and most vulnerable people — the very communities that need adaptation support.
The cost barrier: DAC is expensive and could divert resources from adaptation
DAC is extremely expensive, and the money spent on it could otherwise go directly to adaptation projects that help vulnerable communities. One study puts the levelised cost of capturing and storing a tonne of CO₂ between €160 and over €1,300, depending on electricity costs and plant capacity [1]. To put that in perspective, many adaptation measures — like restoring mangroves for storm protection or installing efficient irrigation — cost far less per tonne of CO₂ avoided or per person protected.
The same study notes that the era of low-cost flying will likely end in a net-zero future [1], which hints at the broader economic trade-offs. If governments and private investors pour billions into DAC, that is money not spent on adaptation. The expert-based policy recommendations in [3] stress that DAC should be governed by principles that ensure 'negative' emissions and long-term storage, but they do not suggest it replaces adaptation. In fact, the authors recommend maintaining separate targets for DAC and for emissions reductions [3], implying that adaptation funding should also be kept distinct and not cannibalized.
The geographic mismatch: where DAC works best vs. where vulnerability is highest
DAC performs best in specific locations — cold climates, for example — which are often far from the most climate-vulnerable communities. One study found that the zeolite adsorbent Na-X in cold conditions (like Canada, Alaska, Greenland, and Antarctica) has the highest known CO₂ adsorption capacity from air (2.54 mmol/g) and the lowest reported DAC operating energy (1.1 MWh per tonne of CO₂) [2]. These are remote, sparsely populated regions.
In contrast, the world's most climate-vulnerable people live in tropical and subtropical regions — small island states, coastal deltas in South Asia, arid zones in Africa. DAC plants in cold climates do nothing to help those communities adapt. Even if DAC were deployed globally, its benefits (reduced atmospheric CO₂) are global and slow-acting, while adaptation needs are local and urgent. The membrane-based DAC approach discussed in [4] is still at an early stage and faces its own energy and cost hurdles, further delaying any potential indirect benefit to vulnerable populations.
About These Sources
This answer is built on 5 peer-reviewed studies — published from 2021 to 2024, 1 from 2024 or later, 5 in Q1 journals, collectively cited 381 times — selected as the most relevant from 6 studies that passed quality screening, drawn from 32 papers retrieved from a database of over 500 million.
Sources used in this answer
The role of direct air carbon capture in decarbonising aviation
Compares two DAC uses for aviation: offsetting fossil jet fuel (cost €160–€1,300/tCO₂) vs. synthetic fuel (€2–€12/kg fuel). Finds offsetting has lower cost but sustainability concerns; synthetic fuel produces 9.8× more emissions for a given electricity mix.
The potential of direct air capture using adsorbents in cold climates
Tests DAC with zeolite adsorbents in cold climates. Reports Na-X achieves 2.54 mmol/g CO₂ adsorption (highest known in air) and lowest operating energy (1.1 MWh/tCO₂) in cold conditions, promising for Canada, Alaska, Greenland, Antarctica.
Climate policy for a net-zero future: ten recommendations for Direct Air Capture
Draws on 125 expert interviews to propose 10 policy recommendations for DACCS, including governance for negative emissions, long-term storage, separate targets, and social acceptance. Emphasizes urgency of managing the DAC transition.
Direct air capture by membranes
Reviews membrane-based DAC as an emerging approach. Notes absorption/adsorption DAC has reached plant scale but consumes large heat and water; membrane DAC is less mature but potentially more energy-efficient.
Emergency deployment of direct air capture as a response to the climate crisis
Models emergency DAC deployment at 1.2–1.9% of global GDP annually. Finds it removes 2.2–2.3 GtCO₂/yr by 2050, 13–20 GtCO₂/yr by 2075, yet warming still reaches 2.4–2.5°C in 2100. Most cost-effective with hydropower or natural gas, not fully renewable systems.