Direct Air Capture: A Critical Pillar of Climate Action

## Introduction

Climate policymakers increasingly recognize that **direct air capture (DAC)** – the process of filtering carbon dioxide (CO₂) out of ambient air – will be a critical component of any serious climate change strategy. This remains true **even if fossil fuel use were halted completely today.** The reason is simple: enormous quantities of CO₂ already reside in the atmosphere, driving warming and destabilizing the climate. Halting emissions stops the bleeding, but it does not clean up the wound. To stabilize global temperatures and restore a safe climate, we must actively remove some of the CO₂ we’ve already emitted. In the words of the U.S. Department of Energy, cutting emissions alone “doesn’t address the trillions of tonnes of carbon dioxide already in our atmosphere” – a legacy that will linger for millennia unless it is drawn down. DAC offers a direct technological means to draw down this legacy carbon and thus has an essential role alongside emissions reductions.

At first glance, the idea of **capturing CO₂ from thin air** might sound quixotic or even unnecessary in a world that shifts rapidly to clean energy. Indeed, skeptics argue that society should focus exclusively on slashing emissions and question whether DAC is an expensive distraction. A December 2023 article in *The Bulletin of the Atomic Scientists* epitomizes this critique, branding DAC “an expensive, dangerous distraction from real climate solutions”. Such critics contend that DAC will always be too costly and energy-intensive to matter, and that pouring resources into it now only diverts effort from cutting emissions. These are serious concerns that deserve a thoughtful response. This essay will engage with those criticisms and outline why, despite the challenges, DAC remains an indispensable tool in the climate policy toolbox. In doing so, it will draw parallels to debates over nuclear energy and hydrogen fuel – two other climate solutions once dismissed as impractical or “techno-utopian” – to show that big infrastructure and long-term technologies can, and must, be pursued alongside immediate measures. It will also situate DAC in the broader context of emissions reduction, climate restoration, and the stability of planetary boundaries. Ultimately, a growing body of research and policy insight shows that **without carbon remooals are likely unachievable**. The task before us is to develop DAC responsibly, as a complement – not an alternative – to deep emissions cuts, in service of a habitable planet for future generations.

## The Need for Carbon Removal After Halting Emissions

If worldwide fossil fuel combustion ceased today, the climate challenge would by no means vanish. Carbon dioxide concentrations have climbed from pre-industrial levels of ~280 parts per million to about **420 ppm** in 2025, and the Earth has already warmed roughly 1.2–1.3°C above pre-industrial temperatures. The **stock of CO₂** in the atmosphere – over 3 trillion tons of heat-trapping gas – would remain, continuing to warm the planet. Natural processes remove CO₂ only very slowly; absent intervention, a large fraction of our CO₂ emissions will persist in the air for centuries to millennia. In fact, climate scientists warn that even a **1.5°C** stabilized warming (the lower Paris Agreement target) may be too high to avoid long-term catastrophic changes like multi-meter sea level rise. James Hansen and colleagues argue that **atmospheric CO₂ must be reduced to below 350 ppm** – a level last seen in the 1980s – to restore climate equilibrium and prevent dangerous feedbacks such as ir†L113-L121】. In their analysis, “keeping warming less than 1.5 °C or CO₂ below 350 ppm now requires extraction of CO₂ from the air” in addition to phasing out fossil fuels. In other words, even emissions, we would likely need to **remove** substantial CO₂ to stop and reverse warming trends.

This need is reflected in the scenarios of the Intergovernmental Panel on Climate Change (IPCC). The IPCC’s Sixth Assessment Report finds that **carbon dioxide removal (CDR) is “required to achieve global and national targets of net zero CO₂ and GHG emissions”**, and furthermore that CDR is a part of **“all modelled scenarios”** that limit warming to 2 °C or lower by 2100. Importantly, the IPCC emphasizes that **CDR “cannot substitute for immediate and deep emissions reductions”**. We must walk on two legs: aggressively cut new emimp up removal of legacy carbon. The Paris Agreement itself acknowledges this dual need, calling for a balance between sources and sinks of emissions in the second half of this century. In practical terms, that means reaching net-zero – and then net-negative – carbon emissions. **Direct air capture is one method to provide those sinks**. Unlike tree-planting or soil carbon storage, DAC can in principle be scaled to **permanently remove CO₂** without vast land requirements, by injecting the CO₂ deep underground or mineralizing it into stable forms. This permanence and scalability make DAC a attractive option for climate “cleanup.” As the U.S. Department of Energy notes, **large-scale carbon removal is essential to limit warming to 1.5 °C** because reducing emissions alone leaves those trillions of tons aloft. Even hardline mitigation proponents increasingly accept that **some form of CDR will be needed to counteract residual emissions** (for example, from agriculture, cement, or air travel) and to draw down excess CO₂ to safer levels. In short, stopping the flow of greenhouse gases into the sky is necessary but not sufficient; we also have to start **mopping up the spilt carbon** if we aim to truly stabilize the climate and perhaps, one day, restore it to pre-industrial conditions.

## What is Direct Air Capture and Why Consider It?

Direct air capture refers to a set of technologies that **chemically scrub CO₂ from ambient air**. DAC systems typically use large fans to pull air through a filter or chemical solution that binds CO₂. The CO₂ is then released in concentrated form (often by heating the filter or changing pressures), and finally the CO₂ is pumped for **permanent storage** in geological formations or converted into stable minerals. The remaining nitrogen-oxygen air is returned to the atmosphere. In effect, DAC machines are artificial “trees” that capture carbon, but unlike biological sinks, the captured carbon can be securely stored for centuries. The appeal of DAC is that it can, in principle, be done **at any location** and scaled to any size, given enough energy and investment. For example, DAC plants could be built near suitable underground storage sites, or co-located with renewable energy farms or geothermal sources to power the energy-intensive capture process. The captured CO₂ is pure and can be injected underground, where it will eventually mineralize into rock, thus achieving a permanent removal from the atmosphere.

It’s important to note that DAC is **not a replacement for cutting emissions**, but a complementary tool. The **primary role of DAC** in climate strategy is to address emissions that are **unavoidable or already emitted**. These include both **“residual” emissions** – the last 10-20% of emissions that are exceedingly difficult to eliminate even in a green economy (think of aviation, some industrial processes, or methane from agriculture) – and **“legacy” emissions** – the CO₂ we emitted in the past that is still warming the planet. By capturing an equivalent amount of CO₂ from the air, DAC can **offset residual emissions** to achieve net-zero, and eventually go beyond net-zero to achieve **net-negative emissions**, actively reducing atmospheric CO₂. The IPCC has made it clear that such removal is *unavoidable* if the world is to reach net-zero targets. In fact, one IPCC pathways analysis found no viable scenario for limiting warming to 1.some carbon removal; if one refuses to deploy CDR, one must accept *overshooting* temperature targets and later trying to cool back down, a risky proposition.

To visualize DAC’s potential, consider the **Orca plant in Iceland**, currently the world’s largest operational DAC facility. *Figure: The Orca direct air capture plant in Hellisheidi, Iceland – the world’s first commercial-scale DAC project – can capture about 4,000 tons of CO₂ per year and sequester it as stone deep underground. Orca’s modular fans and chemical filters, powered by carbon-free geothermal energy, illustrate how DAC can permanently remove CO₂ without relying on arable land or forests.* Orca, built by the Swiss company Climeworks, opened in 2021 and is capable of capturing **4,000 tons of CO₂ per year**, which is then injected underground by Carbfix (an Icelandic partner) and mineralized into rock. While 4,000 tons is a tiny fraction of global emissions, Orca represents a **proof of concept** for DAC’s viability. It also demonstrates DAC’s key advantage: **permanence**. Within a couple of years, the CO₂ that Orca injects into basalt rock turns into solid carbonate minerals, effectively locking away that carbon indefinitely. By contrast, CO₂ absorbed in a forest can be quickly released back to the atmosphere by wildfires, pests, or logging. DAC’s other advantage is its relatively small **physical footprint**. Orca’s installation is modest – essentially a cluster of industrial fans and contactors on a concrete pad – yet it accomplishes what would require hundreds of thousands of trees to achieve annually (and even then, only until those trees die). As DAC technology improves, future plants are envisioned at **much larger scales**: for example, the U.S. company Occidental Petroleum (in partnership with Carbon Engineering) is developing a DAC facility in Texas aiming to capture **50r year**, and has announced plans for 100 such plants by 2035. The U.S. Department of Energy has launched a “Carbon Negative Shot” initiative to drive the cost of carbon removal down below $100 per ton and enable **gigaton-scale** removal by 2030-2035 – in other words, billions of tons per year, which would begin to put a dent in the atmospheric CO₂ surplus.

**Why consider DAC?** Because if we truly commit to stabilizing the climate, we will eventually have to remove CO₂ at massive scale. Natural carbon sinks alone likely cannot accomplish the necessary drawdown. For instance, reforestation and soil improvement are vital and relatively low-cost CDR methods, but they face limits in land availability, saturation, and permanence. The advantage of DAC is that, in theory, it can scale as an industrial enterprise without competing for fertile land or fresh water. It can also deliver **verifiable, trackable carbon removals** – each ton captured can be measured and logged – which is important for climate accountability. These traits have led many experts to view DAC as a *backstop* or insurance policy for the climate: if other measures fall short, DAC (along with other CDR methods) could help compensate. Indeed, the International Energy Agency’s modeling for a net-zero 2050 world includes on the order of **970 million tons per year of DAC by mid-century** (alongside nature-based removals), noting that without DAC and other carbon removals, achieving net-zero would be far more expensive or impossible. In summary, **DAC is being pursued as a crucial tool to balance the carbon budget** – to mop up what we can’t cut – and to gradually restore the atmosphere to safer CO₂ levels.

## Key Criticisms of Direct Air Capture

Despite its envisioned benefits, DAC has attracted significant criticism from scientists, environmentalists, and policy analysts. Before advocating for DAC, it is essential to **engage seriously with these critiques**. The major arguments raised against DAC include:

- **High Cost and Energy Use:** DAC is **currently very expensive**, with estimated costs on the order of \$500 or more per ton of CO₂ removed. This far exceeds the cost of most emissions reduction measures. Critics point out that spending, say, \$500 to remove one ton of CO₂ via DAC makes little sense when that same money could cut twenty tons of CO₂ by installing renewable energy or energy efficiency measures. DAC’s energy requirements are also enormous – pulling CO₂ from air (where it is only ~0.04% by volume) is thermodynamically much harder than capturing CO₂ from concentrated sources like power plant flue gas. The *Bulletin* article calculates that to collect all U.S. CO₂ emissions via DAC at scale would **“require building air-handling capacity larger than the combinedof every HVAC system in the entire country as well as new power plants equal to twice the total power generation capacity of the US today”**. In other words, DAC at climate-significant scales could necessitate an industry of colossal size, potentially devoting a substantial fraction of the nation’s energy just to CO₂ filtering. These daunting numbers lead skeptics to label DAC wildly impractical.

- **Slow Timeline and Unscalable Infrastructure:** Detractors argue that DAC cannot be built up fast enough to impact the near-term climate challenge. The world needs to halve emissions by 2030 to stay on track for 1.5 °C, but DAC is in its infancy – currently removing only on the order of **0.01 million tons of CO₂ per year in total** (tens of thousands of tons globally). Even under optimistic scenarios, scaling to billions of tons per year could take decades. Some scientists, like those in the *Bulletin* piece, argue that *if* DAC is ever needed at large scale, “it won’t be for 50 years, or more” – by which time, hopefully, we would have already transitioned to net-zero without it. Building thousands of DAC plants, plus the infrastructure to transport and store the CO₂, is a generational undertaking akin to constructing the oil and gas industry in reverse. The concern is that we simply don’t have the time to rely on such a long-term “maybe.” Climate impacts are hitting now, and the next ten years are critical; pouring effort into DAC might yield negligible removal by 2030, when what’s needed is immediate emissions cuts.

- **Opportunity Cost – “Distraction” from Real Solutions:** Perhaps the most frequent critique is that DAC could be a **distraction or diversion of resources** from known, effective climate solutions like renewable energy, electrification, and conservation. Every dollar and every megawatt of energy spent on DAC is one not spent replacing coal plants or subsidizing electric buses. The *Bulletin* authors put it starkly: *“Every dollar invested in air capture…makes the planet hot to spending that dollar on emissions avoidance, because that dollar could have abated much more CO₂ if used on cheaper measures. In their view, DAC’s sky-high cost means it yields very little climate benefit now actually results in higher cumulative CO₂ in the atmosphere than if those funds went to, say, deploy solar panels. They argue that society has **“abundant opportunities”** for mitigation at costs below \$25/ton (even below \$0/ton for things that save money) and that these should be exhausted *completely* before we even consider expensive removals. This critique often comes with the metaphor of a **bathtub**: If the atmosphere is a brimming bathtub, pouring in CO₂ via fossil fuels is an open faucet. The priority is to **turn off the faucet** (stop emissions) rather than fool around with a thimble trying to bail out water. Investing in DAC while emissions are still high has been likened to “buying gold-plated thimbles to bail out the tub instead of turning off the faucet”. The worry is that DAC could become a **dangerous distraction**, giving politicians and industries an excuse to delay the hard work of emissions reductions on the pe can suck the carbon out later. In a worst-case scenario, emphasis on future carbon removal could **undermine the urgency of mitigation** (a classic *moral hazard* in climate policy).

- **Techno-solutionism and Feasibility Concerns:** A broader philosophical critique is that DAC exemplifies *“techno-solutionism”* – the idea that every environmental problem can be fixed with a high-tech solution, allowing us to avoid changes in behavior or economic structure. Environmental justice groups and some climate scientists caution that betting on massive technological CO₂ removal is risky and could perpetuate fossil fuel interests. They note that the oil industry, in particular, has embraced DAC: for instance, Occidental Petroleum (Oxy) is a major DAC proponent receiving large federal grants. Skeptics worry this is a ploy: oil companies might use DAC to justify continued oil extraction (by claiming barrels of oil are “net-zero” if the resulting CO₂ is later captured from air). There is also skepticism whether DAC costs can significantly decline. Unlike solar panels or batteries, which got dramatically cheaper with mass production, DAC involves **large chemical plants and heavy infrastructure**, which historically do *not* follow steep learning curves. The *Bulletin* article argues that “the low-hanging fruit was picked long ago” in CO₂ capture tech – industry has separated CO₂ for submarine air and industrial gas processing since the mid-20th century, so DAC new field ripe for breakthroughs. Furthermore, **physics imposes a hard price floor**: the extreme dilution of CO₂ in air means any DAC process will require a lot of energy, and thus money, per ton. As one analysis notes, capturing CO₂ from air can easily be **20 times more costly in capital and many times more in operating costs** than capturing at a power plant, due purely to the low concentration. With such fundamentals, some experts believe DAC will never be cost-competitive or scalable enough to matter for the climate. They advocate focusing on direct emissions cuts and possibly more limited biological carbon sequestration, rather than “Hail Mary” industrial solutions.

These criticisms – cost, speed, opportunity cost, and techno-fix concerns – paint DAC as at best a very long-term, niche option, and at worst a greenwashing tool that delae action. Given these points, is it rational to pursue DAC aggressively now? Proponents argue **yes**, and counter that many of these critiques, while valid to an extent, mihat’s needed to address climate change. In ons, we will rebut these critiques and explain why DAC merits major investment *even as* we prioritize rapid emissions reduction.

## Rebuttal: Why DAC Remains Essential

### Infrastructure Ses – Lessons from Nuclear and Hydrogen

Critics are correct that DAC will require building a **massive infrastructure** unprecedented in climate action. Yet history shows that transforming the energy system inevitably involves big, long-term projects – and that early investment in### Infrastructure Scale and “Too Slow” Concerns: Lessons from Nuclear and Hydrogen

It is true that DAC will require an **unprecedented scale-up** of infrastructure. Critics highlight this to argue DAC is too slow or unscalable to rely on. However, history offers a different lesson: major energy transitions **do** require big, long-term projects – and that is not a reason to avoid them, but rather to start as early as possible. Consider the example of nuclear power. In the 1970s and 1980s, France undertook a massive nuclear energy build-out. It took two decades, billions of francs, and strong political will – but today around 70% of France’s electricity is nuclear and largely carbon-free. That achievement did not happen overnight; it was the result of planning in the face of the 1970s oil crisis and a commitment to a long-term vision. Critics then had said nuclear was *“too slow and expensive”* to help with energy needs, yet by starting when they did, the French ensured that by the time climate change rose to the fore, they had a low-carbon grid ready. The lesson: **time-consuming solutions can pay off big in the long run**, and the sooner you begin, the sooner they become available.

Likewise, think of **green hydrogen**, touted today as a key to decarbonizing steel, shipping, and aviation. Hydrogen energy has been discussed for decades – often met with skepticism as perpetually “a fuel of the future.” Early prototypes were costly and inefficient. But sustained investment and technological progress (electrolyzer improvements, cheaper renewable power) have now made large-scale hydrogen projects viable. Governments are pouring billions into hydrogen hubs because they know that *by 2035 or 2040*, affordable green hydrogen could be indispensable for cutting industrial emissions. If we had abandoned hydrogen research 20 years ago on grounds of cost, we would not have today’s momentum that promises to finally deliver results. The same argument applies to DAC: yes, it is expensive and nascent **today**, but if we **never invest**, it will certainly never be cheap or big enough to matter. If we *do* invest, there is a strong chance that costs can fall and capacity can grow substantially – maybe not to pennies on the dollar, but enough to make a real dent in the climate problem by mid-century. The U.S. DOE’s “Carbon Negative Shot” explicitly aims to push DAC and other removals toward $100/ton by 2032. While $100 is still not cheap, it is five times cheaper than some current DAC costs, and would make large-scale deployment far more plausible. Analogously, offshore wind power was very costly in the 1990s; targeted innovation and deployment programs in Europe drove costs down such that offshore wind is now mainstream. We have to give DAC the opportunity to similarly mature.

Furthermore, the **timeline argument** – *“if we ever need DAC, it won’t be for 50 years”* – can be flipped on its head. If DAC’s real utility will come in a few decades (to draw down overshoot or balance stubborn emissions), then we *must build the foundation now*, because infrastructure at climate-relevant scales takes time. You can’t decide in 2070 that you need billions of tons of removal and instantly conjure a DAC industry; you’d have to have nurtured it through pilot projects in the 2020s, demonstrations in the 2030s, and scaling in the 2040s. This is exactly why many national net-zero strategies include CDR development starting now. The **International Energy Agency (IEA)** notes that there are at least 130 DAC projects announced at various stages; if even a fraction come to fruition, global DAC capacity could reach ~65 million tons a year by 2030, roughly the level required in the IEA’s net-zero scenario for that date. Reaching 65 Mt/yr by 2030 would still be only ~5% of total CO₂ removal needs by mid-century, but it would mark a significant ramp-up – and it is only achievable if policy support continues inL291-L299】. In short, **“too slow” is not a verdict, it’s a challenge**: we know large-scale deployment takes time, so we start as soon as possible to ensure DAC can contribute when we need it. The climate battle will not be won in a year or even a decade; we must think in multi-decade terms.

### Cost and Techno-Economic Uncertainties

The **high cost** of DAC today is undeniable. But the assumption that it will “always” be exorbitant is an assertion we should interrogate. The pessimistic view, as the *Bulletin* authors outline, is that DAC relies on mature industrial components (fans, chemicals, etc.) that won’t benefit from mass-production learning curves, and that physics sets a hard minimum energy cost that translates to perhaps \$100/ton at best. Yet, we have seen many energy technologies surprise on the downside of cost: wind and solar famously outpaced cost forecasts, batteries did as well, and even nuclear costs have fallen in some countries through standardized designs (while rising in others – cost trajectories are not universal). **DAC cost reduction** might come from several avenues:

- **New sorbent materials and processes:** Research is ongoing into better CO₂ absorbents that capture more CO₂ per cycle or require less heat to regenerate. There are also novel DAC methods (e.g., electrochemical approe swing sorbents, passive adsorption panels, etc.) that could potentially leapfrog today’s designs. It’s premature to declare that no innovation will substantially cut DAC costs. Remember that direct air capture itself was barely a few small labs and startups 15 years ago; now multiple companies (Climeworks, Carbon Engineering, Global Thermostat, etc.) are each pursuing different designs. Climeworks is focused on solid sorbent filters, Carbon Engineering uses a liquid solvent in giant cooling tower-like contactors, and others are experimenting with variations. This **competition and diversity** increase the chances of breakthroughs that could lower cost or energy use.

- **Economies of scale and automation:** The first DAC plants (like Orca in Iceland) are essentially hand-built, bespoke units. With scale, manufacturing of DAC modules could be streamlined. There is talk of modular DAC units produced in factories (e.g., packaged as shipping-container-sized blocks) to be assembled into large farms. If hundreds or thousands of identical units are produced, unit costs will drop. The chemical industry provides precedent: complex processes (like synthetic fertilizers) started as small, expensive units and eventually scaled to massive, efficient plants producing commodity chemicals cheaply. **Optimizing supply chains** – sourcing low-cost materials for sorbents, using off-peak power, recycling heat – can all shave costs.

- **Synergistic deployment:** One promising concept is integrating DAC with other systems to share costs. For example, waste heat from industrial facilities or geothermal plants can drive DAC processes, reducing the energy that must be supplied. DAC plants could be co-located with geothermal fields (as in Iceland) or with nuclear plants (using reactor heat) or even with large solar thermal arrays. Additionally, captured CO₂ can be utilized to defray costs: while permanent storage is the goal, interim markets like CO₂-to-fuels or CO₂ for building materials could provide revenue to offset some expenses, as long as the carbon ultimately stays out of the air (e.g., CO₂-based jet fuel that is re-emitted should not count as net removal, but CO₂ locked into concrete could). Such **CO₂ utilization** markets (synthetic fuels, carbontech products) might not handle gigatons, but they could help scale the industry and drive innovation, just as early soltellites, off-grid) helped pave the way for today’s massive solar farms.

The bottom line: DAC is costly now, but **learning-by-doing and innovation** could substantially lower costs over time. A U.S. National Academies report and the DOE both see pathways to under \$200/ton in a decade or two, and aspirationally \$100 or less thereafter. While the *Bulletin* authors may doubt costs “will come down dramatically”, it is worth noting that similar doubts were expressed about renewable energy in the past by incumbents. Caution is warranted, but so is **effort** – we won’t know how cheap DAC can get unless we try. Public investment can absorb the early high costs, funding R&D and first-of-a-kind projects (as governments routinely do for emerging technologies). This is precisely what is happening: the U.S. is investing billions in DAC hubs and prizes, the EU and UK have dedicated funds, and numerous private ventures are drawing in capital. These investments are premised on the understanding that **today’s expense could be tomorrow’s bargain** if it helps avoid climate catastrophe.

### “Distraction” vs. “Portfolio Approach”

The notion that DAC is a “distraction” from real solutions frames climate action as a zero-sum game – every dollar to DAC is a dollar stolen from renewables or efficiency. But climate change is an **all-hands-on-deck crisis** where we need to mobilize vastly more resources overall. It’s not a fixed pie that we’re divvying up, it’s an expanding pie of needed investment. Global investment in clean energy and low-carbon solutions needs to reach into the trillions per year (up from a few hundred billion currently) to meet climate goals. In that context, allocating some tens of billions globally to develop carbon removal is reasonable and proportionate, especially since removal addresses facets of the problem that mitigation does not. We should absolutely prioritize major emissions reductions – that is step one. But it’s possible to **simultaneously** lay groundwork for DAC. In fact, we see this in practice: for example, the **Inflation Reduction Act** in the U.S. massively funds renewables, EVs, and efficiency (hundreds of billions in tax credits) *and also* boosts DAC via the 45Q credit and DAC hub funding. The two are not in conflict in policy; they are complementary line items.

The “gold-plated thimble vs faucet” analogy is a useful caution: obviously, if one had to choose, stopping the emissions source is a higher priority than cleaning up pollution later. No one disputes that. But in reality, **we must do both**: turn down the faucet as fast as possible, and also start bailing water because the tub is overflowing and the faucet can’t be shut off immediately (and some leaks will persist). Critics sometimes imply that talking about DAC will lull society into a false sense of security and thus weaken emission-cutting resolve. This is a risk, but it is not a given – it depends on how the narrative is handled. If every discussion of DAC is careful to frame it as Plan B or a necessary supplement to Plan A (emissions cuts), then the public can understand that **removals are not an excuse to pollute, but a parallel effort to repair damage**. Indeed, many climate advocacy groups have come around to a nuanced position: wary of “mitigation deterrence,” but supportive of research into CDR for the hard realities ahead. The keyword is **“portfolio”**: a portfolio of climate actions ensures resilience. If one approach under-delivers, others can help bridge the gap. Betting solely on an idealized scenario where we cut emissions to zero quickly and never need removal could leave us stranded if that scenario doesn’t fully materialize (which, bluntly, is likely – global emissions are still rising in 2025, so we are already behind on the ideal trajectory).

Another point on opportunity cost: we should consider the **opportunity cost of not developing DAC**. If we neglect removal technologies and it turns out we desperately need them later (to draw down CO₂ or counteract an unforeseen runaway feedback), the cost of having no solution could be measured in **avoidable climate damages**. In economic terms, a modest investment now in DAC R&D is like paying an insurance premium against future climate risk. The cost of insurance is far less than the cost of the disaster one insures against. The *Bulletin* authors might respond that the real insurance is over-investing in mitigation; true, but we can and should insure in multiple ways – primarily by mitigation, secondarily by removal capabilities.

Finally, it is important to recognize that **climate policy is not a one-budget game**. Governments routinely spend on multiple priorities. The existence of a carbon removal program does not inherently diminish the ambition of an emissions reduction program unless political actors choose to pit them against each other. Smart policy design explicitly ties them together: for instance, requiring that any company using CO₂ removal credits must also be meeting aggressive emission reduction benchmarks. That way, removals fill gaps rather than become a free pass. The **IPCC** has been clear on this tandem approach: *“CDR is required… but cannot substitute for immediate and deep reductions”*. We need to walk and chew gum at the same time, as the saying goes.

### Techno-Utopian Trap or Techno-Realism?

The **techno-solutionism** critique of DAC – that it’s a shiny tech fix distracting from systemic change – resonates with many who see climate change as not just a technical problem but a societal one requiring shifts in consumption, equity, and behavior. Indeed, we should be wary of any claim that technology alone will save us. That said, dismissing “tech fixes” outright is equally dangerous. The climate crisis has a **physical, chemical basis** – excess greenhouse gases – which no amount of lifestyle change alone can solve at this point, especially given global population and development needs. We will need technology to decarbonize heavy industry, to provide abundant clean energy, and to remove carbon. The key is to deploy technology **within an ethical framework** and not as an excuse to maintain unsustainable practices.

Take an analogy: in public health, a vaccine is a techno-fix for disease, while improving sanitation and nutrition addresses root causes. We need both. Similarly, tackling fossil fuel dependence and over-consumption (the root causes) is vital, *and* developing DAC (the remedial fix) is also necessary. Far from being mutually exclusive, one co ([

Nine key takeaways about the ‘state of CO2 removal’ in 2024 - Carbon Brief ](https://www.carbonbrief.org/nine-key-takeaways-about-the-state-of-co2-removal-in-2024/#:~:text=But%20the%20use%20of%20CDR,IPCC))y tool shows we are taking the problem seriously at all levels.

One ethical concern is that fossil fuel companies might use DAC to justify continued extraction – for instance, selling oil as “net-zero” by buying DAC offsets. This is a valid concern, and any **policy supporting DAC must preclude abuse**. Regulators could, for example, limit the proportion of emissions that companies are allowed to offset with removals, or enforce that removals are used for genuinely hard-to-eliminate emissions, not to prolong fossil business-as-usual. The voluntary carbon market today is a Wild West of claims; integrating DAC needs rigorous standards. Encouragingly, discussions are underway (e.g., the EU’s Carbon Removal Certification Framework) to establish *quality criteria* for CDR credits. With transparent **monitoring, reporting, and verification (MRV)**, it’s possible to ensure that a ton of CO₂ claimed as removed is actually removed and stored permanently. Such frameworks will help differentiate legitimat greenwashing.

There is also the argument that because oil companies like Occidental Petroleum are investing in DAC (often with subsidies), the whole thing is suspect. It’s wise to be cautious of the oil industry’s motives. But remember, oil companies are involved in *all* forms of energy transition to some degree – they invest in renewables, biofuels, etc., often seeking to shape those solutions to their benefit. Society’s job is to steer these efforts toward the public good. If Occidental builds a DAC plant that actually stores CO₂ securely, we shouldn’t dismiss the CO₂ removed just because an oil firm touched it – we should instead ensure that project was not just a pretense for enhanced oil recovery (using captured CO₂ to pump more oil, which some carbon capture projects have done). In Oxy’s case, they do plan to sell some CO₂ for making synthetic fuels, but also to sell credits for neutralizing emissions. Policymakers can tighten rules to ensure **DAC is used for climate benefit, not oil production** (for instance, disallow CO₂ EOR from DAC if claiming climate incentives). The fact that **DAC doesn’t intrinsically produce revenue** (it costs money to capture and you have to be paid to do it) actually means it’s unlikely to be scaled without strong climate policy – so if it is scaled, it will be because we as a society decided to value climate stability (through carbon pricing or direct support). In other words, DAC will not boom on a profit motive alone; it will boom if and only if we collectively demand carbon removal as a service. This is quite unlike fossil fuels where profit drives extraction regardless of climate damage. So, the techno-ethical landscape of DAC is within our control through governance. We can mandate that it serves as a climate restoration tool rather than a get-out-of-jail-free card for polluters.

### DAC for Climate Restoration and Planetary Boundaries

One of the strongest arguments *for* DAC is the concept of **climate restoration** – actively bringing the Earth system back within safe bounds. The **planetary boundaries** framework, proposed by scientists like Johan Rockström, identifies a stable Holocene-like climate as a boundary for a safe operating space for humanity. We have already overshot that boundary in terms of CO₂ concentration. Pre-industrial levels were 280 ppm, and even the oft-cited 350 ppm (popularized by Dr. James Hansen as a safe target) has been exceeded by a wide margin. As of the mid-2020s, CO₂ is around 420 ppm. This not only fuels higher temperatures, but also **ocean acidification** – CO₂ dissolving in seawater forms carbonic acid, harming marine life. Even if warming is halted at 1.5–2°C, the **absolute level of CO₂** might remain high enough to slowly degrade ice sheets and ecosystems over centuries. **Direct air capture is one of the few tools that can directly lower the total CO₂ in the atmosphere**, helping to gradually return the climate to safer levels. Nature can do this too, but on timescales of thousands of years (e.g., rock weathering). DAC (along with planting forests, enhancing soils, etc.) could accelerate the drawdown.

We should be candid: *climate restoration* to 350 ppm is a very ambitious, multi-generational project. It could require removing on the order of **hundreds of gigatons of CO₂** over the 21st century. Hansen’s study warned that if we delay action and let CO₂ soar, young people in the future might be saddled with the need to remove **1000+ gigatons** at astronomical cost – a burden that would be nearly impossible. By starting removals earlier and keeping emissions low, that burden drops significantly (perhaps a few hundred gigatons, much of which could be handled by natural means if nurtured properly). So DAC, scaled up alongside reforestation and other CDR, could eventually help reduce CO₂ concentrations after mid-century, preventing long-term climate impacts like massive sea level rise that even 1.5–2°C might lock in. In policy terms, this is about **meeting the Paris Agreement’s stretch goals** not just of halting warming, but potentially reversing it in the 2100s. The Paris text even implies net-negative emissions in the long run (“balance between sources and sinks” and achieving temperature stabilization, which for 1.5°C likely means net negative in the back half of the century).

Another critical role of DAC is in **managing overshoot**. Many climate scenarios now project that we will exceed 1.5°C temporarily before coming back down. That comeback is only possible with negative emissions. If we find ourselves in 2040 at 1.6°C despite best efforts, having a mature DAC industry could be what allows us to start cooling the planet back to safer levels. Without DAC or other CDR, we’d be stuck with whatever peak temperature occurs. DAC thus acts as a form of *climate control knob* that, while not an instant fix, gives future generations the ability to gradually reduce atmospheric GHG levels if needed. Importantly, this is distinct from geoengineering schemes like solar radiation management (dimming the sun) – DAC addresses the root cause (excess CO₂) rather than masking it. As such, it aligns better with the precautionary principle: fix the problem at its source.

Planetary stability isn’t just about temperature; **CO₂ removal addresses other imbalances**. For example, high CO₂ is pushing the ocean outside the range of chemical conditions experienced by marine species for millions of years. Removals that bring CO₂ down will mitigate ocean acidification, giving coral reefs and shellfish a better chance to survive. High CO₂ also affects plant growth and nutrient cycles on land in complex ways; dialing CO₂ back could help restore more normal patterns for ecosystems. None of this happens overnight – it’s a long-term planetary maintenance task. But it underscores that the ultimate goal is not just net-zero emissions, but a **balanced Earth system**. In that grand perspective, DAC is a powerful lever. It is essentially a way to **increase the planet’s capacity to heal** by artificially enhancing a natural process (CO₂ uptake from air). Given the scale of human disturbance, harnessing such tools may be necessary to return to equilibrium.

### Technical, Political, and Ethical Implementation Considerations

In moving from theory to practice, there are several considerations to ensure DAC is implemented responsibly and effectively:

- **Energy and Technology:** DAC’s high energy demand means it must be powered by clean energy to deliver a net benefit. This creates a symbiosis: the expansion of DAC can further justify building more renewables, nuclear, or other zero-carbon power sources. One must ensure that DAC plants are sited and timed such that they use surplus or dedicated clean power, not siphon electricity away from other needs. For instance, a large DAC operation might pair with a large solar farm plus storage, or use off-peak wind power that might otherwise be curtailed. Some DAC designs could even use waste heat from industrial processes. Technically, the field is evolving: companies are experimenting with **solid sorbents vs. liquid solvents**, different regeneration methods (temperature swing, pressure swing), and novel ideas like direct ocean capture (taking CO₂ out of seawater, which in turn draws more from air). As these technologies compete, we may discover more efficient methods. Governments can spur this by funding R&D and demonstration projects across a range of approaches, as the U.S. and EU are beginning to do. Another technical aspect is **CO₂ storage**: we have to securely store the captured CO₂ for the long term. Fortunately, geological storage – injecting CO₂ into deep saline aquifers or basalt formations – is a well-studied approach, with large-scale tests showing that CO₂ can mineralize or stay trapped for millennia. The capacity for geological storage globally is likely on the order of *trillions* of tons of CO₂, far more than we’d ever need to inject to stabilize climate. The challenge is ensuring monitoring and managing any risks (like ensuring injected CO₂ does not leak or induce seismicity). This calls for robust regulation akin to how we manage natural gas storage or underground waste disposal. **Pipeline infrastructure** may also be needed to transport CO₂ from DAC plants to suitable storage sites, unless they are co-located. Planning this network in advance (as part of a broader CO₂ transport for carbon capture utilization and storage, CCUS) will be important. Notably, CO₂ pipelines exist today in places like Texas, used mostly for oil recovery; repurposing and expanding them for dedicated CO₂ sequestration is part of the CCUS vision. All these technical pieces – capture tech, energy supply, transport, storage – must come together. It’s complex but very much achievable with engineering know-how and money; none of it violates physics or materials limits (the main hurdle is cost, as discussed).

- **Policy and Governance:** Getting DAC to scale will require smart policy. Carbon removal currently has no natural market incentive – the “product” (a cleaner atmosphere) is a public good that no single actor can monetize easily. Thus, government support is crucial to kickstart the industry. This can take forms like **tax credits** (e.g., the US 45Q credit of \$180/ton for DAC-based CO₂ storage), direct government procurement of carbon removal (as launched by the US and some coalitions of companies), grants for R&D, and regulations that effectively mandate removals (for instance, California’s Low Carbon Fuel Standard now awards credits for DAC). Policymakers also need to integrate CDR into climate targets. Countries could include CDR in their nationally determined contributions under Paris, or set specific CDR targets (the EU, for example, has a goal for 5 Mt/yr of removals by 2030 as a start). One delicate aspect is preventing “double counting” – ensuring that if one country or company sells a removal credit, that removed carbon isn’t also claimed by someone else. International accounting rules for CDR will be needed. Additionally, governance is needed to address the **moral hazard** issue: policies should not allow, say, a new coal plant to be built today on the promise of future DAC offsets. Some have suggested a *“removal obligation”* approach: for every ton of CO₂ a fossil fuel company emits beyond a certain cap, it must also fund removal of an equivalent ton (or a fraction thereof), essentially internalizing the cost of cleanup. This kind of policy could align incentives by making DAC part of doing business in a net-zero world rather than a get-out-of-jail card. We also will need institutions for oversight of storage sites (to verify permanence) and certification of DAC technologies (to avoid snake oil). In sum, significant **policy architecture** must be built around DAC – but this is true for all climate solutions (think of the elaborate markets and subsidies around renewables or the regulations for vehicle emissions). It’s a manageable task with international cooperation and lessons from existing frameworks (like the Clean Development Mechanism experience, which taught us pitfalls to avoid in carbon crediting).

- **Ethical and Equity Issues:** Ethically, the development of DAC raises questions of intergenerational justice and equity. On one hand, one could argue it is *unethical not to develop DAC*, since failing to do so leaves future generations with fewer options to deal with the climate mess they inherit. We enjoyed the benefits of fossil fuels; we have a duty to invest in cleaning up the byproducts. Hansen et al. made this point: **today’s young people will bear the burden of negative emissions later if we shirk action now**. On the other hand, there are concerns about how DAC is paid for and who controls it. If DAC is purely a commercial enterprise run by a few corporations, will it be deployed in the best interests of the global poor (who are most vulnerable to climate change)? There is a risk of climate colonialism – imagine rich countries overshooting emission targets and then covering their excess by funding massive DAC projects in poorer countries (using their land or resources for carbon warehouses). Depending on perspective this could be seen as either a new form of extraction or as an economic opportunity for host countries. The ethical approach would be to ensure **inclusive governance**: maybe international bodies or public trusts should have a stake in carbon removal projects, community consent should be required for siting, and benefits (like job creation or infrastructure) should accrue locally. Another equity aspect is resource use: DAC will use land, energy, and materials. Its land footprint is relatively small per ton (especially compared to afforestation or BECCS), but not zero – facilities and renewable plants need space. Care must be taken to avoid siting DAC on valued ecosystems or indigenous lands without consent. Its water use depends on the process (some DAC units require water for cooling or for the chemical reaction); in arid regions, using a lot of water for DAC could be contentious unless paired with desalination or other measures. These issues require engagement with stakeholders and possibly setting guidelines (for instance, prioritizing brownfield or non-arable land for DAC plants).

- **Public Perception and Ethical Framing:** DAC and carbon removal must be communicated carefully to the public. There is a valid worry that emphasizing “sucking carbon out of the air” might lead people to think climate change is solved, undermining support for other actions. Effective climate communication should emphasize *both* the importance of stopping emissions and the need to clean up legacy carbon – often comparing it to how we handle pollution in other domains (we both stop dumping sewage in rivers **and** sometimes clean up legacy polluted sites). Ethically, we have to avoid letting carbon removal be framed as *license to pollute*. That can be achieved by strong climate laws (e.g., fossil phase-out dates, emission performance standards) that removal cannot override, but only supplement. For example, an airline might reach a mandated 90% emissions reduction and use DAC offsets for the last 10% it cannot eliminate – that’s constructive. But opening a new coal mine because “we’ll do DAC later” would be reprehensible. Fortunately, the direction of policy – at least in many jurisdictions – is toward tighter emission limits with removal helping to get to net-zero, not justify new emissions.

- **Environmental Impact:** Compared to many industrial activities, DAC is relatively clean – it doesn’t emit toxins or conventional pollution; its “emission” is just cleaned air. However, the construction of large DAC farms will have some local impacts (noise from fans, visual impacts of industrial structures, possibly mining impacts for materials used in sorbents or building the equipment). Proper environmental assessments should be required, and the public should have input on projects. One positive point is that DAC, if powered by renewables, has a far smaller footprint and impact than equivalent carbon capture via biomass plantations, which could consume vast land and water. In a way, DAC is a way to **avoid burdening the biosphere further**: rather than require an area the size of India to be blanketed in new forests or bioenergy crops (which some high-overshoot scenarios show), a much smaller area filled with machines could do the same carbon removal job, leaving natural ecosystems untouched or even allowing some farmland to revert to nature. So from a **planetary stewardship** perspective, DAC might be a tool that saves forests and preserves biodiversity by taking on the carbon removal task that otherwise we would push onto land.

In summary, the implementation of DAC must be done thoughtfully, guided by science and ethics. It’s not just about building machines, but integrating them into our socio-economic system in a fair and effective way. The good news is that this conversation is already happening at high levels, and there are many eyes on ensuring DAC doesn’t become a wild west. If done right, DAC could become a pillar of **climate justice** – cleaning up the atmospheric commons in a way that benefits all and is paid for by those most responsible for the pollution.

## Conclusion: A Dual Pillar Strategy for Climate Stability

Direct Air Capture is not a silver bullet, nor is it a mirage. It is best viewed as a **crucial supporting pillar** in a broader climate strategy, whose primary pillar remains the rapid elimination of fossil fuel emissions. Serious climate policy cannot afford to ignore either pillar. Yes, we must throw the kitchen sink at cutting emissions: transition the global energy system to renewable and nuclear power, electrify transport, reform industry and agriculture, and pursue conservation and efficiency with vigor. Those efforts address the future flow of emissions – the “faucet.” But to address the stock already in the atmosphere and the trickle of unavoidable emissions, we need carbon removal. DAC stands out among removal options for its permanence and scalability, if we invest to make it viable.

The criticisms of DAC – high cost, slow timeline, potential misuse – are not reasons to abandon DAC; they are challenges to **meet with smart policy and innovation**. Dismissing DAC outright would be akin to a denial of the severity of our predicament, just as relying on DAC alone would be a denial of the urgency of mitigation. The rational path is to do **both**: cut emissions aggressively *and* develop DAC to deal with the aftermath. One might think of it like approaching a financial debt crisis: you stop going deeper into debt (cut emissions), and you figure out how to pay down the principal (remove carbon) – doing only one and not the other would fail to solve the problem.

A world where fossil fuels were completely halted today would still be a world in need of DAC. And realistically, we’re not halting fossil use today – it will take a couple of decades to wind down even with optimistic actions. Meanwhile, the climate doesn’t pause. That’s why every major analysis, from the **IPCC** to the **IEA**, includes some role for carbon removal in meeting climate targets. We should heed both the activists who say “focus on real solutions” and the scientists who say “we’ll need removal too.” These messages are not contradictory: we focus on emissions *first*, but we also prepare for removals *simultaneously*.

In the debates around nuclear energy and hydrogen, we saw similar arguments. Detractors called them distractions, proponents insisted they were essential for the harder parts of decarbonization. Today, we see that nuclear provides virtually carbon-free power in many countries (albeit with challenges), and hydrogen is gearing up to tackle emissions that electricity can’t easily address. The early investments and difficult persistence in those arenas are now paying off (or likely will). DAC is on the cusp of a similar trajectory. It is not an easy road – it’s a moonshot to be sure – but the climate crisis demands moonshots. As the U.S. DOE put it, the climate crisis calls for a different kind of moonshot, one that can deliver **“abundant, affordable, and reliable”** clean solutions within the decade. Carbon removal is explicitly one of those solutions, to address what cutting emissions alone cannot.

For policymakers, the imperative is clear: **support emissions reduction and removal, not one or the other.** Develop stringent climate policies that drive down pollution, and in parallel, fund and regulate DAC and other CDR so they become effective and equitable. Foster international cooperation on carbon removal, because the atmosphere is shared – a ton removed anywhere benefits everywhere. And cultivate public understanding that cleaning up carbon is part of climate responsibility, not a get-out-of-jail-free card for polluters. If we strike that balance, DAC will enhance, not hinder, our fight against climate change.

In the end, **direct air capture is about taking responsibility**. It’s humanity saying: we will not only stop poisoning the atmosphere, we will also try to heal it. Even if fossil fuel emissions stopped today, taking responsibility for the carbon already emitted is the next step toward a sustainable and just climate future. With sober realism about its challenges, but also determination to overcome them, DAC can become a critical tool to safeguard a livable planet.

## Works Cited

- House, Kurt Zenz, et al. “Direct Air Capture: An Expensive, Dangerous Distraction from Real Climate Solutions.” *Bulletin of the Atomic Scientists*, 15 Dec. 2023, thebulletin.org/2023/12/direct-air-capture-an-expensive-dangerous-distraction-from-real-climate-solutions/.

- Intergovernmental Panel on Climate Change (IPCC). *Climate Change 2022: Mitigation of Climate Change – Carbon Dioxide Removal Fact Sheet*. IPCC, Apr. 2022, https://www.ipcc.ch/report/ar6/wg3/downloads/outreach/IPCC_AR6_WGIII_Factsheet_CDR.pdf.

- United States, Department of Energy. “Carbon Negative Shot.” *Energy.gov*, U.S. Department of Energy, Nov. 2021, energy.gov/topics/carbon-negative-shot.

- Dunne, Daisy, and Robert McSweeney. “Nine Key Takeaways about the ‘State of CO2 Removal’ in 2024.” *Carbon Brief*, 4 June 2024, www.carbonbrief.org/nine-key-takeaways-about-the-state-of-co2-removal-in-2024/.

- Agence France-Presse. “World’s Biggest Machine Capturing Carbon from Air Turned On in Iceland.” *The Guardian*, 8 Sept. 2021, www.theguardian.com/environment/2021/sep/09/worlds-biggest-plant-to-turn-carbon-dioxide-into-rock-opens-in-iceland-orca.

- “In Pictures: World’s Largest Carbon Capture Plant in Action.” *BBC Science Focus Magazine*, 13 Sept. 2021, www.sciencefocus.com/future-technology/carbon-capture-in-action.

- Hansen, James, et al. “Young People’s Burden: Requirement of Negative CO2 Emissions.” *Earth System Dynamics*, vol. 8, no. 3, 2017, pp. 577–616. European Geosciences Union, doi:10.5194/esd-8-577-2017.

- International Energy Agency. “Direct Air Capture – Tracking Report.” *IEA*, 25 Apr. 2024, www.iea.org/reports/direct-air-capture-2024.