Claim

A 98-day river alkalinity-enhancement trial in Norway reported 250 ± 30 tonnes CO2-equivalent of gross carbon dioxide removal after adding 1,480 tonnes of calcite, with no significant increase in most measured adverse water-quality indicators apart from phosphate.

Type QUANTITATIVE · truth-evaluable: yes · status at snapshot: ACTIVE · created seq 19587

37 words; atomic claims are usually under 25a comma-separated series may list several propositions

Referenced 126 times: checked 2, looked up by assistants 0, viewed 86, shared 38. A count of attention, not evidence.

Topics

Climate · 1efd24fe Energy · 1efd24fe

Assessment

Supported

Score: 0.9121 under ledger-default@0.3.0 at snapshot 27745

2 of 4 review checks done · 1 counted · 1 by the author only

2 independent evidence lineages · review checks 1 of 4 · stability MEDIUM

Main unresolved issue: 4 counted evidence items have no independence review; repeats of one origin may be counted as several coverage:44ce862b-8592-80c4-8c28-21cd11b54403

Not yet independently audited.Evidence reviewed so far supports this claim, but only 1 of 4 review checks has been done.A quoted passage from cdrxiv.org was not found on the page when Galedra fetched it.

Why?

Strongest counted support: The preprint reports trial duration, calcite addition, gross CDR estimate, and the stated water-quality result. weight 1.800000 evidence

Suppressed as dependent: The passage directly reports the 98-day trial, 1,480-tonne calcite addition, 250 ± 30 tonnes CO2-equivalent gross CDR, and stated water-quality qualification.

Review gaps: qualifiers reviewed, opposing search done, independence reviewed

What would most change this: One independent, direct measurement that contradicts this claim would move it from Supported to Unresolved.

Hide calculation

0.9121 under ledger-default@0.3.0 at snapshot 27745 · state Supported · Review checks: 1 of 4 · stability MEDIUM · 4 sources, 2 independent lineages

Model ledger-default@0.3.0 (the default model, not the answer) · snapshot 27745 · trace sha256:9dfce446e1733ca15a70d070dbfcb719333b5baf601cf9ff73b5bf00a092210f

Last changed at entry seq 25501; nothing logged since has borne on this claim.

How the number was reached

Each counted link is weighed by multiplying the factors the model declares; a factor it does not declare is not shown. Every factor name below links to what that number means.

Link	Working	Weight	Counted as
7c7543d7 support	relevance MODERATE 0.6 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	0.540000	0.540000
3460cf45 support	relevance DIRECT 2.0 × observation DIRECT_TEXT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	1.800000	0.000000 (dependent strongest only, kept 8cddf894)
e5208db3 qualify	relevance DIRECT 2.0 × observation MEASUREMENT 1.0 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	2.000000	0.000000 (non directional)
8cddf894 support	relevance DIRECT 2.0 × observation DATASET_RESULT 0.9 × interpretation 0 steps, 1 − 0.15 × 0 1.000000 × authenticity UNVERIFIED 1.0 × extraction UNVERIFIED 1.0 × provenance INDEPENDENT 1.0 × edition NAMED_OR_UNRELATED 1	1.800000	1.800000

prior 0.50 → log-odds 0.000000 + 2.340000 (the counted weights) = 2.340000 → probability 0.9121

Under neighbouring settings of the same model: 0.8373 to 0.9544, a spread of 0.1171.

Half-even rounding, six places for weights and four for the probability. The same inputs under the same model reproduce this exactly; that is what the trace hash above is for. How a score is worked out explains every factor, why it is there, and what the model sets it to.

Your view

Registered views

Nobody has registered a view yet.

Registered views are personal belief, not evidence: they never change Galedra's assessment. Affiliations are self-declared and shown only for groups of 5 or more.

Checked as part of

Statements this claim was broken out of. The claim is scored on its own; a statement's reading only counts its claims.

“A 98-day river alkalinity-enhancement trial in Norway reported 250 ± 30 tonnes CO2-equivalent of gross carbon dioxide removal after adding 1,480 tonnes of...” · 1 claim · 29 September 2026
“A 98-day river alkalinity-enhancement trial in Norway reported 250 ± 30 tonnes CO2-equivalent of gross carbon dioxide removal after adding 1,480 tonnes of...” · 1 claim · 29 September 2026

Evidence for

The preprint reports trial duration, calcite addition, gross CDR estimate, and the stated water-quality result.

From Quantified Carbon Dioxide Removal from an Alkalinity Addition Field Trial in the Kvina River, Norway Read 2026-09-29 Relevance DIRECT Steps 0 Counted
The passage directly reports the 98-day trial, 1,480-tonne calcite addition, 250 ± 30 tonnes CO2-equivalent gross CDR, and stated water-quality qualification.

From Quantified Carbon Dioxide Removal from an Alkalinity Addition Field Trial in the Kvina River, Norway Read 2026-09-29 Relevance DIRECT Steps 0 Counted
Independent methodology coverage confirms the Kvina project duration and 1,480-tonne additional dose and describes a measurement-and-model framework for quantifying river-mouth DIC and accounting for retention, counterfactual weathering, emissions, and uncertainty.

From How the world's first River Alkalinity Enhancement credits were quantified Read 2026-09-29 Relevance MODERATE Steps 0 Counted

This corroborates the trial setup and quantification context but does not independently reproduce the preprint's 250 ± 30 t CO2e gross estimate.

Evidence against

None.

Qualifications

The 250 ± 30 t CO2e value is a 98-day gross, control-relative estimate for additional calcite within an existing Norwegian liming programme, with phosphate as an exception among measured water-quality indicators and site-specific applicability.

From Quantified Carbon Dioxide Removal from an Alkalinity Addition Field Trial in the Kvina River, Norway Read 2026-09-29 Relevance DIRECT Steps 0 Counted

Clarifies baseline/control, additional dosing, duration, gross-versus-net translation, jurisdiction, and water-quality scope.

Suppressed as dependent

Evidence	Group	Kept instead
10cdd744		8cddf894

Inferences

Concluded from

None.

Used as a premise in

None.

An inference is interpretation, not evidence: it never changes the assessment of its conclusion. Each premise is a claim with its own evidence.

Threads

None. Threads are for disagreements about how a determination was made — a statement whose figures are not in the passage it rests on, two sources that may share an origin. Something about the world belongs in the evidence above.

Claim edges

None. Edges are stored and displayed; v0.1 does not propagate probability across them.

Review checklist

Review checks: 1 of 4

2 checks by this claim's own author, alongside the independent review above. 1 QUALIFIER CHECK · 1 EVIDENCE VERIFICATION. A check by the person who recorded a claim does not raise its review coverage.

Check	Done	By
qualifiers reviewed	no
opposing search done	no
independence reviewed	no
primary source reviewed	yes	3460cf45, e5208db3, 8cddf894

Summary

Supported. The main support is: Independent methodology coverage confirms the Kvina project duration and 1,480-tonne additional dose and describes a measurement-and-model framework for quantifying river-mouth DIC and accounting for retention, counterfactual weathering, emissions, and uncertainty. e1ba0296

1 further item repeats the same origin and is not independent evidence. 10cdd744

Qualifier: The 250 ± 30 t CO2e value is a 98-day gross, control-relative estimate for additional calcite within an existing Norwegian liming programme, with phosphate as an exception among measured water-quality indicators and site-specific applicability. 69cef25b

Review checks: 1 of 4. coverage:44ce862b-8592-80c4-8c28-21cd11b54403

Generated by stub-v0.1; every sentence cites graph ids.

Contribution history

seq	event	detail
19587	APPENDED
19588	ACCEPT	AUTOMATIC_AFTER_VALIDATION
19593	LINK_EVIDENCE	by 1efd24fe (accepted)
19596	TASK_RESULT	by 1efd24fe (accepted)
19636	LINK_EVIDENCE	by 1efd24fe (accepted)
25500	TASK_RESULT	by 1efd24fe (accepted)

Score trace

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  "code_hash": "sha256:c61a6fdf35a754a0d7e958df149036a083c0eaeb7d2d2e52704ec32b0c36def7",
  "contested": false,
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