Removing CO2 from the Atmosphere to Reverse Climate Change
Direct Air Capture (DAC) represents one of humanity's most ambitious technological responses to climate change. Unlike traditional carbon capture technologies that intercept CO2 from power plants or industrial facilities, DAC systems extract carbon dioxide directly from the ambient air around us—the same air we breathe every day.
This distinction is crucial. Point-source carbon capture can only address emissions from active facilities, but DAC can remove historical emissions that have accumulated in the atmosphere over centuries of industrialization. It's not just about slowing climate change—it's about reversing it.
As of 2025, atmospheric CO2 concentrations hover around 420 parts per million (ppm), far above the pre-industrial level of 280 ppm. Scientists warn that to limit global warming to 1.5°C, we must not only eliminate emissions but also remove approximately 10 billion tons of CO2 from the atmosphere annually by 2050.
Natural carbon sinks—forests, oceans, soil—currently remove about 10 billion tons per year. But we emit over 35 billion tons annually. The math is unforgiving: we need technology to bridge this gap. DAC is one of the most promising solutions.
DAC is a form of CDR, which encompasses any process that removes CO2 from the atmosphere and stores it durably. Other CDR methods include afforestation, enhanced weathering, ocean alkalinization, and biochar. DAC stands out for its scalability, measurability, and permanence when paired with geological storage.
At its core, DAC technology uses chemical processes to separate CO2 from air. While the specific chemistry varies, all DAC systems follow these fundamental steps:
The challenge lies in the extremely low concentration of CO2 in ambient air—just 0.04%. For comparison, industrial flue gas contains 3-15% CO2. This means DAC systems must process enormous volumes of air to capture meaningful amounts of carbon.
DAC SYSTEM FLOW
AIR (415 ppm CO2) ──→ [CONTACTOR] ──→ AIR (350 ppm CO2)
│
↓
[SORBENT SATURATED]
│
↓ (Heat/Pressure)
[REGENERATION]
│
↓
PURE CO2 (>95%)
│
┌───────────────┴────────────────┐
↓ ↓
[GEOLOGICAL STORAGE] [UTILIZATION]
(Permanent removal) (Products)
DAC technology offers several unique advantages that make it indispensable in the fight against climate change:
As of 2025, operational DAC facilities worldwide capture approximately 40,000 tons of CO2 annually. While this is a tiny fraction of what's needed, the technology is rapidly scaling. Companies like Climeworks, Carbon Engineering, and Global Thermostat are building facilities that will capture millions of tons per year by 2030.
Solid sorbent systems use structured materials, typically functionalized with amine compounds, to capture CO2. When air passes through these materials, CO2 molecules chemically bond to the surface. These systems operate in cycles: adsorption (capturing CO2) and regeneration (releasing CO2).
The Adsorption Phase: Ambient air flows through contactors filled with solid sorbent material. At room temperature (15-25°C), the amine groups on the sorbent surface react with CO2, forming carbamate bonds. This process is exothermic—it releases a small amount of heat.
The Regeneration Phase: Once the sorbent is saturated (typically 80-90% of its capacity), it's heated to 80-120°C. This relatively low temperature breaks the chemical bonds, releasing pure CO2 gas. The sorbent is then cooled and ready for another cycle.
Climeworks, a Swiss company, pioneered commercial solid sorbent DAC. Their "Orca" facility in Iceland, operational since 2021, captures 4,000 tons of CO2 annually using 8 modular collector units. Each unit contains proprietary amine-functionalized filters.
The facility uses geothermal energy from Iceland's Hellisheidi power plant, making the process carbon-neutral. Captured CO2 is dissolved in water and injected into basalt rock formations, where it mineralizes into solid carbonate within two years—permanent storage.
Advantages of Solid Sorbent DAC:
Challenges:
Liquid solvent systems use alkaline solutions (typically potassium hydroxide or sodium hydroxide) to absorb CO2 from air. This technology is based on mature industrial processes used in paper mills and fertilizer production for decades.
The Process: Air is drawn through a contactor where it meets a fine spray or flows through a packed column filled with flowing solvent. The alkaline solution reacts with CO2 to form carbonate salts. The CO2-rich solution (called "rich liquor") is then heated to very high temperatures (>900°C) in a calciner, decomposing the carbonate back into CO2 gas and regenerating the solvent.
LIQUID SOLVENT PROCESS
Air + KOH → KHCO3 (potassium bicarbonate)
↓
Heated to 900°C
↓
KHCO3 → KOH + CO2 (pure)
↓
KOH recycled to contactor
Canadian company Carbon Engineering uses liquid potassium hydroxide solvent in their DAC design. Their pilot plant in Squamish, British Columbia, has operated since 2015, demonstrating the technology at scale.
CE's first commercial-scale plant, under construction in Texas, will capture 1 million tons of CO2 per year—250 times larger than Climeworks' Orca. The captured CO2 will be used for enhanced oil recovery and synthetic fuel production.
Advantages of Liquid Solvent DAC:
Challenges:
Electrochemical DAC: This newer approach uses electrochemical cells to capture and release CO2 through voltage changes rather than thermal cycles. When voltage is applied, CO2 is captured; when reversed, CO2 is released. This could dramatically reduce energy requirements, as electricity is easier to decarbonize than high-temperature heat.
Moisture Swing DAC: Some materials can capture CO2 when dry and release it when exposed to moisture. This eliminates the need for thermal energy entirely, instead using the natural water cycle. However, the technology is still in early research stages.
Solid Sorbent: Lower energy (2-3 MWh/ton CO2), higher material costs, proven at small scale
Liquid Solvent: Higher energy (5-8 MWh/ton CO2), lower material costs, proven at larger scale
Electrochemical: Potentially lowest energy (1-2 MWh/ton CO2), early development stage
Energy is the primary cost driver for DAC. Extracting CO2 from 400 ppm concentrations requires significant work—thermodynamically, the minimum energy is about 0.4 MWh per ton of CO2. In practice, today's technologies require 2-8 MWh per ton, depending on the system.
For context, 1 MWh could power an average American home for about one month. Capturing 1 billion tons of CO2 annually using current technology would require 2,000-8,000 TWh—roughly 10-40% of global electricity production. This is why renewable energy integration is critical.
Iceland's Orca facility demonstrates the ideal: abundant geothermal energy provides both electricity and heat for regeneration. The facility's carbon footprint is essentially zero, as all energy comes from renewable sources.
Future DAC facilities will likely cluster near renewable energy resources: geothermal zones (Iceland, East Africa), solar deserts (Southwest US, Middle East, Australia), or offshore wind farms.
Current DAC costs range from $600-1,000 per ton of CO2 for solid sorbent systems to $400-600 for liquid solvent systems. This is far above the social cost of carbon (~$50/ton) and carbon credit prices ($20-100/ton).
However, costs are falling rapidly:
This cost reduction follows a learning curve similar to solar panels and batteries. Every doubling of deployed capacity reduces costs by 15-25%. Government incentives like the US Inflation Reduction Act's $180/ton tax credit for DAC accelerate deployment.
Who pays for DAC? Currently, three revenue streams exist:
In 2020, Microsoft committed to being carbon negative by 2030. The company contracts with DAC providers like Climeworks to purchase carbon removal credits. In 2023, Microsoft bought removal of 10,000 tons for approximately $6-7 million—roughly $600-700 per ton.
Microsoft views this as both climate action and strategic investment. As costs fall, early purchases support the industry's growth while securing long-term carbon removal capacity.
To reach gigatons of annual capture, DAC must overcome several hurdles:
Despite these challenges, the industry is moving fast. Announced projects will increase global DAC capacity from 40,000 tons/year in 2025 to over 5 million tons/year by 2030.
Capturing CO2 is only half the solution. Without permanent storage, the carbon returns to the atmosphere, negating the climate benefit. This is why the WIA-ENE-050 standard emphasizes verification of storage permanence.
The most common storage method injects compressed CO2 into deep underground formations (800-3,000 meters). At these depths, pressure and temperature create supercritical CO2—a dense, liquid-like state ideal for storage.
Storage Formations:
Safety Mechanisms: Multiple barriers prevent CO2 leakage:
The Sleipner project in Norway has safely stored 1 million tons of CO2 per year in a saline aquifer since 1996—over 25 million tons total. Annual seismic surveys confirm the CO2 remains contained. This 30-year track record demonstrates geological storage safety.
Mineralization accelerates a natural process: CO2 reacts with minerals (calcium, magnesium) in rocks to form solid carbonates—essentially limestone. This is how nature has stored carbon for millions of years.
The CarbFix Method: Pioneered in Iceland, this approach dissolves CO2 in water and injects it into basalt rock formations. The carbonated water (like sparkling water) reacts with calcium and magnesium in the basalt:
CO2 + H2O + CaSiO3 → CaCO3 + SiO2 + H2O (dissolved CO2 + basalt → calcite + silica + water)
Remarkably, this reaction completes in less than 2 years—far faster than the centuries predicted. Over 90% of injected CO2 mineralizes into solid rock, providing permanent storage guaranteed for >10,000 years.
Advantages:
Suitable basalt formations exist on all continents and offshore. The Columbia River Basalt in the northwestern US alone could store 100 billion tons of CO2. Iceland's basalts could store Europe's emissions for decades. The potential far exceeds global needs.
Some captured CO2 can be used in products, but only if carbon remains locked up long-term:
Not Acceptable for Climate Credits:
The WIA-ENE-050 standard requires life-cycle assessment for all utilization pathways to ensure net carbon removal.
Storage sites require rigorous monitoring:
Third-party verification ensures compliance with standards like ISO 27916. Blockchain-based immutable records provide permanent proof of storage for carbon credit registries.
By 2030, the IPCC projects we need to remove 100-300 million tons of CO2 annually through technological means. While this is a tiny fraction of the 10 billion tons needed by 2050, it represents a crucial milestone. Currently announced DAC projects will reach 5-10 million tons by 2030—a significant gap remains.
Research focuses on several frontiers:
WIA-ENE-050 and similar standards are crucial for scaling DAC. They ensure:
Just as internet protocols enabled the digital revolution, carbon removal standards can enable a climate restoration revolution.
Governments worldwide are mobilizing support:
Private investment is accelerating. Major corporations (Microsoft, Google, Meta, Stripe, Shopify) commit billions to carbon removal purchases, creating demand that drives innovation and scale.
Imagine a world where DAC facilities powered by abundant renewable energy dot the landscape near every major geological storage site. Standardized, mass-produced modules capture billions of tons of CO2 annually at costs below $100 per ton.
Atmospheric CO2 concentrations peak in the 2030s and begin declining. By 2050, a global network removes 10 billion tons per year, balancing residual emissions and beginning the slow reversal of climate change. By 2100, we return to pre-industrial CO2 levels.
This is not fantasy—it's an engineerable future. The technology exists. The physics is understood. The economics are improving rapidly. What's needed is coordinated action: research funding, policy support, corporate commitments, and public engagement.
Individual actions matter:
But most importantly: stay informed and engaged. Climate change is solvable, but only if we act with urgency and scale. Direct Air Capture represents hope backed by science and engineering. The future is not predetermined—we are writing it now.
This Korean philosophy guides the WIA-ENE-050 standard. Direct Air Capture embodies this principle: technology deployed not for profit alone, but for the benefit of all people, future generations, and the planet we share.
By standardizing DAC systems, we enable a global cooperative effort to restore our atmosphere. Every ton of CO2 removed benefits everyone, everywhere. This is technology in service of humanity's greatest challenge—and our greatest opportunity to show what we can achieve together.