What this dataset is
Let the data free. Mycelium is an open-access database of corporate greenhouse gas emissions: companies and their scope 1, 2 and 3 figures, held in kgCO2e, alongside each company's Mycelium Score and Transparency Score and links to the reports the figures came from. Anyone can search it, read any company's profile, and cite what they find, without an account and without payment.
Coverage
The database currently holds 15,049 emissions disclosures from 13,532 companies, spanning reporting years 2000 to 2026. The companies span 87 countries and 151 industry classifications. These figures are read live from the database as this page renders, so they are current, not marketing copy.
Where the data comes from
The core of the database is what companies themselves have published: sustainability reports, annual reports and regulatory filings. Company identity is anchored to official registries, including Companies House and the GLEIF Legal Entity Identifier system. Companies that claim their listing can also submit figures directly. Our data sources page describes each source, and the methodology explains how figures are extracted, checked, scored and estimated.
One honest caveat: much of the extraction is automated, including the use of large language models to read filings, and that process makes mistakes. Errors and omissions are inevitable, and you should verify figures against the source documents (linked from each profile) before relying on them for decisions.
Reported or estimated: every figure says which
This distinction is the core of the methodology. Every emissions line in the database is tagged with its provenance: company-reported, meaning the company disclosed the figure in its own filing or submission, or Mycelium-estimated, meaning we modelled it against industry benchmarks because the company did not report it. Profiles, exports and the API all carry the tag.
If you use the data, preserve that distinction. An estimated figure must never be presented as something the company disclosed. That single rule protects the companies in the database, your own work, and ours.
How to access it
Browsing is free and always will be. Here is the honest trade that keeps it that way: Mycelium takes no external funding, and licensed bulk access is what pays for free public access.
- Browse: free, no account. Search the database, browse by industry, or open any company page.
- API: api.mycelium.global, key-gated and free to request. Start at API access.
- MCP server: free and keyless, built for AI assistants and agents. See the MCP page for how to connect.
- Bulk export: licensed. Start at API access and tell us what you need; academic and carbon accountant access may be free or reduced.
Licence
Use of the data on this site is governed by the Emissions Data Terms of Use. Programmatic access is licensed under the Commercial, Academic and Carbon Accountant API licences. Those pages are the authoritative wording; read them there.
Citing the data
Any use of the data must include this citation, with a hyperlink:
'Data sourced from Mycelium Network, available at mycelium.global'
