The nature footprint of your Claude Code sessions. The tool turns your token use into energy, then into the pressures that drive nature loss at each data centre: climate, water, pollution and land. It adds them up in one unit, species·yr, with ReCiPe 2016.
lamarck · all transcripts on disk · 597 sessions
Tokens 18.2 B (97% cache reads)
Energy 819.3 kWh
CO₂e 267.9 kgCO₂e (235.2 kgCO₂e electricity at 287 g/kWh, 32.8 kgCO₂e hardware manufacturing)
Water 4.3 m³ (147.5 L cooling on site, 4.2 m³ to make the electricity)
Nature 7.8e-7 to 1.2e-6 species·yr, as if 53 to 82 m² of land lost all its species for a year
If every request ran at one site:
Site Grid CO₂e species·yr Climate Water Pollution Land Basin stress
Ashburn VA SRVC 254.4 kgCO₂e 7.8e-7 91% 3% 3% 3% Low, 6% withdrawn
New Carlisle IN RFCW 373.2 kgCO₂e 1.1e-6 91% 2% 5% 2% High, 71% withdrawn
Memphis TN SRTV 368.5 kgCO₂e 1.1e-6 91% 2% 5% 2% Low, 0% withdrawn
Council Bluffs IA* MROW 377.1 kgCO₂e 1.2e-6 87% 2% 9% 2% Low, 5% withdrawn
The Dalles OR* NWPP 268.9 kgCO₂e 8.6e-7 88% 3% 6% 4% Low, 1% withdrawn
species·yr: species lost, integrated over time (ReCiPe 2016, ecosystem quality).
Basin stress: WRI Aqueduct 4.0 withdrawals over renewable supply, where cooling water is drawn.
* Assumed site. Anthropic does not publish how it splits requests between sites.
Order of magnitude only. See METHODOLOGY.md.
80 requests to non-Claude models are left out.
A carbon figure is the same wherever the tonne is emitted. A water figure is not. One litre drawn from a basin that uses 6% of its renewable supply has little effect. The same litre drawn from a basin that uses 71% of it competes with farms, towns and rivers. The TNFD guidance for the Technology and Communications sector asks data centres to report exactly this: the local water stress score, with WRI Aqueduct as the reference.
lamarck keeps the energy model of claude-carbon and adds the nature side.
| IPBES pressure | What the tool counts | Source |
|---|---|---|
| Climate change | CO₂e of the grid that supplies each site, plus hardware manufacturing | US EPA eGRID2023, Schneider et al. 2025 |
| Overexploitation | Water for cooling and for power plants, cooling at the watershed of the site | Jegham et al. 2025, Pfister et al. 2009 |
| Pollution | NOx and SO₂ of the grid: acidification and ozone | US EPA eGRID2023 |
| Ecosystem use | Land of the generation mix, extraction included | Lovering et al. 2022 |
| Invasive alien species | Not counted: no path for electricity |
ReCiPe 2016 converts each pressure into species·yr, and the report divides the total by the mean species density to give an area: the m² that would lose all their species for a year. The answer surprised us: at every site, climate is 87-91% of the total. For AI use, the nature footprint follows the carbon footprint. The local water signal stays in its own column, because no species number captures it yet.
The five pressures are the drivers of nature loss that IPBES names. Darwin (darwindata.io) measures them for company supply chains, and this tool applies the same reading to one developer's AI use.
In Claude Code, the plugin does everything: it installs the binary and adds the status line.
/plugin marketplace add darwin-data/lamarck
/plugin install lamarck@darwin-data
/lamarck:setup
From a terminal, the same in two commands. No Rust needed: the script downloads the release binary for macOS or Linux and checks its SHA-256.
curl -fsSL https://raw.githubusercontent.com/darwin-data/lamarck/main/install.sh | sh
lamarck install-statuslineWith Homebrew: brew install darwin-data/tap/lamarck. With Rust:
cargo install --git https://github.com/darwin-data/lamarck.
lamarck install-statusline sets the status line in ~/.claude/settings.json and
copies the old file to settings.json.bak-lamarck. If you already have a status line,
it stays on the first line: lamarck runs it through --wrap.
⚡ 2.3 kWh 💧 12.3 L 🏭 670 gCO₂e ≈ 🚗 2.7 km 🌱 0.13–0.22 PDF·m²·yr ≈ 📄 2.8 A4 ↳ last turn +199 gCO₂e · ♻️ 97% cache
📅 today ⚡ 10.5 kWh 💧 55.4 L 🏭 3.0 kgCO₂e ≈ 🚗 12 km 🌱 0.60–0.97 PDF·m²·yr ≈ 📄 13 A4 17 sessions
- The first line is the current session, subagents included.
last turncounts what was sent since your last prompt.cacheis the share of the prompt read from the prompt cache: the higher, the cheaper each request. - The second line is every session since local midnight.
--no-todayremoves it. - The PDF·m²·yr range runs over the candidate sites, as in the report. The two
≈give an order of magnitude: kilometres in a typical petrol car, and a familiar area for the middle of the range. METHODOLOGY.md gives the sources. - Each metric has its own colour, and the equivalents are grey. Set
NO_COLORto get plain text. - A day of transcripts is about 100 MB. lamarck keeps a scan of each file in
~/.cache/lamarckand re-reads only the files that changed: about 65 ms per call.
The plugin adds /lamarck:report (the full report) and
/lamarck:setup (install and status line).
| Command | Output |
|---|---|
lamarck report [--since YYYY-MM-DD] [--project TEXT] [--json] |
Totals over the transcripts on disk |
lamarck statusline [--wrap COMMAND] [--no-today] |
The status line: session, then today (reads its JSON on stdin) |
lamarck install-statusline |
Sets the status line in Claude Code settings, and keeps the existing one |
lamarck sites |
The candidate sites: grid, emissions and land per MWh, basin, and why each one is there |
Claude Code deletes transcripts after about 30 days. The report covers what is still on disk. Nothing leaves your machine.
Order of magnitude only. Do not use these numbers for regulatory reporting. Anthropic does not publish where each request runs, so the tool shows each site as a separate case. See METHODOLOGY.md for every factor and its source.
- Energy and CO₂e factors: claude-carbon by Gaëtan Wittebolle (MIT), from Jegham et al. 2025.
- Water stress: WRI Aqueduct 4.0 (CC BY 4.0).
- Grid emissions and mix: US EPA eGRID2023 (public domain).
- Land-use intensity: Lovering et al. 2022, PLOS ONE 17(7): e0270155.
- Characterisation: ReCiPe 2016 v1.1, RIVM Report 2016-0104a.
Jean-Baptiste de Lamarck (1744–1829) was a French naturalist. In 1802 he was one of the first
to use the word biology, and Darwin cited him in On the Origin of Species. Until v0.3.0
the tool was named claude-nature: lamarck install-statusline moves an old status line to
the new name.
MIT licence.