The Intergovernmental Panel on Climate Change (IPCC) and other leading scientific bodies are clear: cutting carbon emissions alone won’t be enough to reach the world’s climate goals. Even with rapid decarbonisation, we’ll need to remove billions of tonnes of CO₂ from the atmosphere in the coming decades to stay within safe climate limits.
That’s where carbon removal technologies come in. Designed to target the CO₂ already in our atmosphere, these tools are crucial for tackling the historic emissions responsible for driving the climate crisis and offer a scalable way to address our carbon legacy.
So, what carbon removal technologies does the world have to draw on? Which are already available, and which still need to be developed? How do they work and what impact do they tangibly deliver to mitigate climate change? This short guide provides a high-level overview of some of the most promising solutions out there.
What is carbon dioxide removal technology?
Carbon removal technology is designed to take carbon dioxide out of the atmosphere and lock it away permanently. Unlike emissions reduction solutions, which focus on cutting future emissions, and carbon capture technologies, which stop new CO₂ emissions from being released from an industrial source — carbon removal technology actively draws down CO₂ that’s already in the air. This makes it an essential tool for reversing the historic emissions that are warming our planet today.
This guide focuses on engineered carbon removal solutions — that is, tools that have been purpose-built to remove CO₂ from the atmosphere. Nature is already doing its part: forests, soils, oceans and wetlands are constantly working to absorb carbon. And when we actively support those systems — through things like afforestation or soil carbon storage — we unlock all sorts of ecological benefits too. These approaches are key to building a broad and balanced portfolio of carbon removal solutions.
But even in the best conditions, they can’t keep up with the scale and speed of today’s emissions. They also tend to be harder to measure, verify and manage over time — especially when land use or long-term durability is in question. That’s why we need engineered solutions, which are easy to track, scale, and are built with the carbon removal challenge squarely in mind.
Carbon dioxide removal (CDR) technologies come in many shapes and sizes. While they can be simply grouped into broad categories, the diversity of these tools mean there’s often overlap, with many technologies that don't fit neatly into one box. We’ve put together a high-level overview of a portfolio of carbon removal solutions, highlighting their unique mechanisms, potential, and challenges, to give you a sense of what each brings to the table.
Direct air capture carbon removal technology
How it works: Direct air capture carbon removal technology strips CO₂ directly from the air. Fans draw in ambient air, and reactive materials selectively filter out the CO₂. The gas can then be stored deep underground or fixed in products like building materials, which durably store the carbon for thousands of years.
💡Learn more: How does direct air capture work?
DAC benefits
- Permanent: DAC carbon removal can be combined with permanent storage, locking carbon away for thousands of years;
- Measurable: Each step of the process can be accurately tracked, making it easy to verify how much CO₂ has been removed;
- Location-flexible: DAC can be built almost anywhere with access to clean energy and CO₂ storage or reuse options;
- Scalable: With three commercial plants already on the ground, our DAC technology is gearing up to remove millions of tonnes of CO₂ from the atmosphere;
- High-purity CO₂ output: DAC CO₂ commands a particularly high molecular purity, making it ideal for multiple use cases;
- Minimal land footprint: DAC carbon removal requires less land than solutions that rely on the growth of trees or other natural matter, meaning less disruption to ecosystems;
- Compatible with clean energy: Direct air capture systems are designed to run using renewable electricity, supporting the clean energy transition and helping to solve curtailment;
- Continuous process: Direct air capture carbon removal technology can be run around the clock to absorb CO2 from the air.
DAC limitations
- High energy demand: Powering DAC can require a lot of energy, which is why at Mission Zero we’ve pioneered an efficient, heat-free electrochemical direct air capture technology;
- Reliant on supporting policy: Stable, long-term policy support backed by regulation is needed to complement early momentum from the voluntary carbon market and to unlock larger-scale project financing;
- Cost: direct air capture price is often over-simplified. Although DAC can be pricier than some other already-scaled carbon removal technologies, it’s also been designed to solely and efficiently pull CO2 out of the atmosphere, with its price tag set to drop as the technology develops.
💡Learn more: Debunking the $100 fallacy: What does direct air capture CO2 actually cost?
Biomass-based carbon removal technology
How it works:
Biomass — like wood, crop waste, or algae — naturally absorbs CO₂ as it grows. When that biomass is processed (often by burning it for energy), the resulting emissions can be captured and stored underground, taking atmospheric CO₂ out of circulation. This approach, known as BECCS (bioenergy with carbon capture and storage), is the most widely known. Biochar is also a popular biomass based CDR solution, which can be added to soil as a fertiliser.
Biomass benefits
- Dual benefit: Many biomass-based systems remove CO₂ and produce useful byproducts like energy, fertiliser (biochar), or liquid fuels;
- Established tech: Carbon dioxide removal technology is still relatively new as an industry, with biomass-based removal methods reflecting a large share of the current market;
- Gaseous CO₂ stream: Some methods of biomass based CDR – primarily BECCS – generate a gaseous CO₂ stream that’s relatively easy to capture and store;
- Waste-compatible: Many approaches can run on agricultural or forestry waste, reducing the need for dedicated land use.
Biomass limitations
- Land and resource intensive: Once waste feedstocks are exhausted scaling up may require dedicated crops, putting pressure on food systems and biodiversity – some model pathways state that landmass up to five times the size of India would need to be used to grow sufficient biomass;
- Supply chain challenges: Ensuring the biomass is sustainably sourced and traceable is a major hurdle;
- Measurement challenges: Biomass-based methods are exposed to environmental variables, making performance less predictable and harder to monitor.
Enhanced weathering carbon removal technology
How it works:
Enhanced weathering speeds up a natural process where certain types of rock — like basalt or silicate — react with CO₂ and lock it away in stable minerals. By crushing these rocks and spreading them over land or into the ocean, they absorb CO₂ from the air or water and turn it into carbonates that store carbon for thousands of years.
Enhanced weathering benefits
- Durable storage: CO₂ is locked away in solid mineral form, offering long-term storage;
- Co-benefits: On land, crushed rock can help improve soil quality; in the ocean, it may help counter ocean acidification;
- Simple technology: The process itself is fairly straightforward — crushing and spreading rock is an established practice in industries like agriculture and mining.
Enhanced weathering limitations
- Material intensive: Requires mining, grinding, and transporting large volumes of rock — a linear process that has to be run in batches rather than continuously removing carbon;
- Measurement challenges: Tracking exactly how much CO₂ is removed, and how fast, remains a scientific challenge;
- Ecosystem impact: Changing soil chemistry at scale could pose risks and needs careful monitoring.
Ocean-based carbon removal technologies
How it works:
Ocean-based carbon removal taps into the ocean’s natural ability to absorb CO₂. This can be enhanced in a few different ways — like adding alkaline materials to seawater (ocean alkalinity enhancement), or sinking carbon-rich biomass to the deep sea. Some methods also produce a usable CO₂ stream for storage or reuse.
Ocean-based removal benefits
- Potential scale: Oceans cover 70% of the Earth’s surface and already absorb around 25% of global CO₂ emissions;
- Diverse approaches: From electrochemical ocean CDR to mineral addition, ocean carbon removal offers a range of deployment options;
- By-product value: Some pathways generate useful outputs like industrial acids or desalinated water, creating potential revenue beyond carbon removal;
- Gaseous CO₂ stream: Certain methods produce a concentrated CO₂ stream that can be stored.
Ocean-based removal limitations
- Regulatory complexity: Activities in international waters face tight legal and political scrutiny, potentially slowing deployment;
- Ecological risk: Intervening in ocean systems carries greater environmental uncertainty and potential for unintended side effects;
- Measurement challenges: Weather, tides, and marine conditions can affect performance and make measurement and verification tricky;
- Public perception: Ocean-based carbon dioxide removal technology can trigger public concern due to fears about interfering with marine ecosystems and the unknowns of large-scale ocean intervention, making transparency and community engagement critical.
Unlocking the full potential of carbon removal technology
Carbon removal is no silver bullet solution — but it’s an essential part of our climate crisis mitigation toolkit. To tackle the CO₂ already in our atmosphere, we need carbon removal systems that are durable, scalable, and ready to deliver at pace.
Direct air capture carbon removal is flexible, precise, and purpose-built for one job: removing CO₂ from the air. That said, no single technology can do it all – a portfolio of solutions working together is critical to meet the needs of different geographies and industries.
The challenge ahead is clear: accelerate innovation, scale up deployment, and build the policy foundations to support a thriving carbon removal industry.
