Biochar vs Enhanced Rock Weathering: Compare Carbon Credits
Biochar and Enhanced Rock Weathering both generate carbon credits, and buyers often shortlist them together, but they get there in different ways. They differ in how the carbon is captured or the emissions avoided, how long the benefit lasts, how the result is measured and verified, and what a tonne typically costs. This page sets the two side by side on the same criteria so you can see where they genuinely diverge.
Everything below is drawn from the projects listed on Carbon Compared right now: how many projects of each type we list, where they operate, which standards accredit them, and the range of prices currently listed. Carbon Compared is free, independent, and does not sell credits, so this is a comparison rather than a recommendation. Pricing for individual projects, permanence data, and independent BeZero Carbon and Calyx Global ratings are available with a free account.
How they work
Each approach starts from a different mechanism. The summaries below are the same ones used on the Biochar and Enhanced Rock Weathering project type pages.
Biochar
Biochar is a charcoal-like material produced by heating agricultural or forestry residues without oxygen (pyrolysis). The process locks carbon that plants captured from the atmosphere into a highly stable form, which is then applied to soils or used in construction materials.
Biochar credits are popular with buyers who want durable, measurable carbon removal at mid-range prices, with strong co-benefits: biochar improves soil fertility, water retention, and crop yields where it is applied.
Enhanced Rock Weathering
Enhanced rock weathering accelerates a natural process: silicate rocks such as basalt are crushed and spread on farmland, where they react with CO₂ and rainwater to form stable bicarbonates that eventually wash into the ocean.
The result is permanent carbon removal with agricultural co-benefits: the rock dust can improve soil pH and release nutrients. Measurement methodologies are maturing quickly, and several registries now accredit weathering projects.
Permanence
Permanence is how long the carbon stays out of the atmosphere, and it is often the clearest difference between two project types. Carbon locked into rock or deep geology is measured in thousands of years, while carbon held in living biomass depends on the land staying intact and protected. Avoided emissions are a different case: nothing is being stored, so the question shifts to how confident you can be that those emissions really would have happened otherwise. Permanence figures for individual projects are shown with a free account.
Biochar
Every listed project is carbon removal: CO₂ is physically taken out of the atmosphere and stored.
Enhanced Rock Weathering
Every listed project is carbon removal: CO₂ is physically taken out of the atmosphere and stored.
Cost
The ranges below are the lowest, highest, and median prices listed on Carbon Compared for each type today, not global market prices, and they move as listings change. Prices vary within a project type as much as between types, so read them as a starting point. Our carbon credit price guide explains what sits behind the numbers.
Biochar
$100 to $330 per tonne CO₂e
Median $165 across 7 listed prices
Enhanced Rock Weathering
$250 to $360 per tonne CO₂e
Median $310 across 4 listed prices
Availability on Carbon Compared
How many projects of each type we currently list, the countries they operate in, and the verification standards that accredit them.
Biochar
7 projects listed
Accreditations
Isometric, Global C-Sink, Verra, Carbon Standards International, Other, Puro.Earth, Mexican CAR, CSI and CapChar
Enhanced Rock Weathering
5 projects listed
Accreditations
Isometric, Puro.Earth, Other, Mexican CAR, CSI and Verra
Which should you choose
We do not rank project types, and there is no single right answer. Biochar and Enhanced Rock Weathering suit different goals, budgets, and reporting requirements, so the useful move is to answer these questions for your own purchase before you shortlist.
What claim do you need to make?
Removal and avoidance support different statements in a climate report, and some frameworks treat them separately.
How long does the carbon need to stay stored?
If your target is built around durable storage, permanence is the filter to apply first.
What is your budget per tonne, and across how many tonnes?
Volume changes what is realistic, and a fixed budget usually means trading price against durability.
When do you need the credits?
Some projects can deliver issued credits now, while others sell ahead of issuance with a longer wait.
How much evidence do you need?
Consider the verification standard, the methodology, and whether independent raters such as BeZero Carbon and Calyx Global have assessed the project.
Do co-benefits matter to your stakeholders?
Health, biodiversity, and community outcomes vary widely and are often the deciding factor when two options look similar on carbon.
Plenty of buyers end up with both. A common approach is a portfolio that mixes tonnes available today with an allocation to more durable removal, adjusted over time as budgets and targets change. Compare the individual projects rather than the categories: the spread within Biochar and within Enhanced Rock Weathering is often wider than the gap between them.
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Each credit = 1 tCO₂e