Abundance Potential

Assessment scope

Development

A modelling approach that estimates annual global CO₂ production from human metabolism using measurements across the lifespan, population figures, and body-weight data, with the stated aim of informing carbon budgets and local carbon measurements.

Baseline

Existing carbon accounting before use of this estimate; the article does not establish that current budgets omit metabolic CO₂.

Population

Global population; climate researchers and modelers are the direct users, with broader public benefits only if improved accounting informs decisions.

Geography

Global, including densely populated urban areas where metabolic CO₂ may affect local measurements.

Target assumptions

The estimate is adopted and improves carbon accounting or predictions; metabolic CO₂ remains clearly distinguished from fossil-fuel emissions. The reported estimates cover 1985–2015 and are model outputs, not a direct count of every breath.

Five dimensions

Human wellbeing

Unknown · The supplied evidence describes potential scientific uses but does not establish an effect on health, safety, or other direct human wellbeing outcomes. Sources: evidence-1749

Affordability and access

Unknown · The supplied evidence does not describe changes to the price or availability of essentials or useful capabilities. Sources: evidence-1749

Reach and fairness

Unknown · The evidence gives global estimates and possible research uses but does not assess who can access the benefits or how benefits and burdens are distributed. Sources: evidence-1745, evidence-1749

Environment and resources

1/4 · More complete carbon budgets and improved interpretation of local measurements could modestly support environmental accounting and predictions about carbon-reduction efforts. The report presents these as possible uses, not demonstrated environmental improvements. Sources: evidence-1747, evidence-1749

Scientific capability

2/4 · The study combines thousands of measurements with population and body-weight data to estimate a previously unclear global carbon flow. This is a meaningful, bounded addition to carbon-cycle accounting; the evidence does not show that it has improved models or decisions in practice. Sources: evidence-1744, evidence-1748, evidence-1749

Evidence, confidence and timing

Evidence maturity

Finding: Prototype pilot. A modelling study produced global estimates for 1985–2015 from measurements and population and body-weight data. The supplied evidence describes a research estimate, not operational deployment.

Societal benefit: Early speculative. Improved carbon budgets and predictions are proposed potential benefits; the evidence does not report a demonstrated improvement to a model, program, or outcome.

Confidence: Low. The source reports a defined modelling result and inputs, but supplies no further detail on model uncertainty and describes downstream benefits as potential rather than demonstrated.

Conditional time horizon: Unknown. The article gives no adoption schedule or timeframe for any resulting improvement to carbon budgets or predictions.

Possible benefits

• If researchers adopt the estimate and account for it appropriately, it could make carbon budgets and dense-urban carbon measurements more complete and help refine predictions about carbon-reduction efforts. Sources: evidence-1747, evidence-1749

Risks and possible harms

• If metabolic CO₂ is misclassified as fossil-fuel emissions, carbon accounting or public interpretation could be distorted. The report emphasizes that these carbon flows differ and does not quantify climate effects. Affected groups: Researchers, policymakers, and the public relying on carbon accounting or climate explanations. Sources: evidence-1746, evidence-1747

Distribution and adoption

Who might be excluded

• Distribution of benefits remains uncertain.

Adoption barriers

• Use in carbon-budget workflows and any resulting model improvement are not demonstrated; the report also provides no further detail on model uncertainty. Sources: evidence-1748, evidence-1749

Assumptions and conditions that could change the assessment

• The estimate is useful only if adopted in carbon accounting and kept distinct from fossil-fuel emissions, since most metabolic CO₂ comes from recently cycled carbon in food. Sources: evidence-1746, evidence-1747, evidence-1749
• Evidence from independent validation and practical use showing improved carbon-budget accuracy or predictions would support a higher assessment; evidence that the estimate does not improve those outputs, or that uncertainty undermines its usefulness, would support a lower one. Sources: evidence-1748, evidence-1749

Citations

1. evidence-1744 · Human bodies produce 2 billion metric tons of CO2 a year just by staying alive · N; o; t; ; l; i; s; t; e; d; ; o; n; ; p; u; b; l; i; s; h; e; r; ; p; a; g; e · 10.1016/j.lanplh.2026.101546 · Captured publisher article text · Open source
2. evidence-1745 · Human bodies produce 2 billion metric tons of CO2 a year just by staying alive · N; o; t; ; l; i; s; t; e; d; ; o; n; ; p; u; b; l; i; s; h; e; r; ; p; a; g; e · 10.1016/j.lanplh.2026.101546 · Captured publisher article text · Open source
3. evidence-1746 · Human bodies produce 2 billion metric tons of CO2 a year just by staying alive · N; o; t; ; l; i; s; t; e; d; ; o; n; ; p; u; b; l; i; s; h; e; r; ; p; a; g; e · 10.1016/j.lanplh.2026.101546 · Captured publisher article text · Open source
4. evidence-1747 · Human bodies produce 2 billion metric tons of CO2 a year just by staying alive · N; o; t; ; l; i; s; t; e; d; ; o; n; ; p; u; b; l; i; s; h; e; r; ; p; a; g; e · 10.1016/j.lanplh.2026.101546 · Captured publisher article text · Open source
5. evidence-1748 · Human bodies produce 2 billion metric tons of CO2 a year just by staying alive · N; o; t; ; l; i; s; t; e; d; ; o; n; ; p; u; b; l; i; s; h; e; r; ; p; a; g; e · 10.1016/j.lanplh.2026.101546 · Captured publisher article text · Open source
6. evidence-1749 · Human bodies produce 2 billion metric tons of CO2 a year just by staying alive · N; o; t; ; l; i; s; t; e; d; ; o; n; ; p; u; b; l; i; s; h; e; r; ; p; a; g; e · 10.1016/j.lanplh.2026.101546 · Captured publisher article text · Open source