Carbon removal challenge 2026: what works and what does not

01 The scale of carbon removal needed

The Intergovernmental Panel on Climate Change (IPCC) has made clear that reducing emissions alone will not be enough to limit warming to 1.5°C — carbon dioxide removal (CDR) is essential. The IPCC estimates that the world needs to remove between 5 and 16 gigatonnes of CO2 per year by 2050 to meet climate targets. Current CDR capacity, excluding conventional afforestation, is measured in the hundreds of thousands of tonnes — a gap of roughly four orders of magnitude that must be closed in under 25 years.

This scale-up challenge has no precedent. Building a carbon removal industry of the required size would mean deploying infrastructure comparable to the entire global oil and gas sector, but in reverse — capturing and storing carbon rather than extracting and burning it. The 2026 Carbon Removal Challenge and similar initiatives are accelerating innovation, but the gap between demonstrated technology and industrial-scale deployment remains enormous.

02 Direct air capture technology explained

Direct air capture (DAC) is a technology that removes CO2 directly from ambient air using chemical sorbents or solvents. Air is drawn through a contactor where the sorbent selectively binds CO2, which is then released through a regeneration process and concentrated for storage or utilization. The advantage of DAC is that it can be located anywhere — near geological storage sites, renewable energy sources, or industrial facilities — and it removes carbon regardless of when or where it was emitted.

The disadvantage is cost and energy intensity. DAC requires significant energy to power fans, heat sorbents for regeneration, and compress CO2 for storage. Current costs range from $600-1,000 per ton, far above the $100 target that would make DAC competitive at scale. Companies like Climeworks, Carbon Engineering (operating as part of Occidental Petroleum), and CarbonCapture Inc. are building commercial facilities, but the technology remains in early commercialization with substantial cost reductions still needed.

03 Nature-based solutions and their limits

Nature-based solutions — afforestation, reforestation, soil carbon sequestration, wetland restoration, and biochar — leverage natural biological processes to remove CO2. These approaches are generally cheaper than technological solutions, offer co-benefits like biodiversity and water security, and can be deployed immediately. Afforestation at $30-100 per ton and biochar at $50-150 per ton are among the most cost-effective removal methods available.

However, nature-based solutions have inherent limits. Land competition with agriculture and human settlements constrains how much forest can be planted. Carbon stored in forests is vulnerable to reversal through fire, disease, and climate change itself — a drought or wildfire can release decades of stored carbon in days. Measurement and verification of nature-based removals are difficult, and permanence — ensuring the carbon stays removed for centuries — cannot be guaranteed with biological systems. These limits mean nature-based solutions alone cannot close the removal gap.

04 Ocean alkalinity enhancement

Ocean alkalinity enhancement (OAE) is an emerging approach that involves adding alkaline minerals to seawater to increase the ocean's capacity to absorb and store CO2. When alkaline minerals dissolve in seawater, they shift the carbonate chemistry equilibrium, allowing more atmospheric CO2 to dissolve while counteracting ocean acidification. The potential is large — the ocean already absorbs about a quarter of human CO2 emissions — but the technology is in early research stages.

Challenges include the energy and cost of grinding and distributing minerals at scale, potential ecological impacts of altering ocean chemistry, and measurement and verification of carbon removal. Several startups and research groups are conducting field trials, and OAE is generating significant interest as a potentially scalable approach that could complement direct air capture. However, it remains years behind DAC in deployment readiness and faces its own set of unknowns.

05 The cost per ton of carbon removed

Cost per ton is the defining metric for carbon removal viability. At current costs, DAC is roughly 8-10x more expensive than nature-based solutions, but nature-based solutions face permanence and scale constraints that DAC does not. The goal across the industry is to drive all methods below $100 per ton, the threshold at which carbon removal becomes economically meaningful at the scale needed. Costs are declining as learning curves progress, but the rate of decline is uncertain and varies by technology.

The voluntary carbon market currently provides most of the revenue for carbon removal, but voluntary markets are small relative to the need. Carbon removal could become a trillion-dollar industry if it scales to the levels the IPCC says are necessary, but only if costs fall and if durable demand exists — either from carbon pricing, regulatory mandates, or corporate net-zero commitments that require real, verified removals rather than cheap offsets.

06 Which approaches are scaling fastest

Afforestation and reforestation are scaling fastest in absolute terms because they use established land management practices and require no new technology. Biochar is growing rapidly as a byproduct of biomass processing. DAC is scaling fastest in terms of year-over-year capacity growth rate, though from a very small base — from thousands of tonnes to tens of thousands of tonnes between 2023 and 2026. Enhanced weathering and ocean alkalinity enhancement are in pilot phases with rapid growth in research funding but limited commercial deployment.

The Carbon Removal Challenge and similar innovation prizes are identifying promising approaches and accelerating their path from concept to pilot. Winners of the 2026 challenge showcased approaches spanning electrochemical DAC, mineral carbonation, and novel biological methods. The diversity of approaches is a strength — no single technology is likely to meet the entire removal need, and a portfolio strategy reduces the risk of any single approach failing to scale.

07 What policy support is needed

Carbon removal at scale requires policy support that does not yet exist in adequate form. The key needs are: durable demand signals, either through carbon pricing or procurement mandates; measurement, reporting, and verification (MRV) standards that ensure claimed removals are real and permanent; and public investment in research, development, and demonstration to drive down costs. The U.S. Inflation Reduction Act included significant tax credits for direct air capture, and the EU is developing a Carbon Removal Certification Framework, but these are early steps.

The risk is that carbon removal becomes a moral hazard — an excuse to delay emission reductions on the assumption that future technology will clean up the carbon later. The IPCC is explicit that removals are necessary in addition to, not instead of, deep emission cuts. Getting this balance right — deploying enough removal to meet climate goals without undermining the urgency of emission reduction — is the central policy challenge of the carbon removal era.