Adverse Climate Outcome (ACO) meaning

Adverse Climate Outcome (ACO) describes, in contract practice, any climate‑harming consequence that directly arises from (i) the non‑performance of an affected obligation, or (ii) the invocation or enforcement of a force majeure clause in relation to that non‑performance. It is not defined in UK or Irish legislation or case law; it is a descriptive contractual term used in environmental and ESG clauses to allocate risk, set mitigation duties, and inform reporting. An ACO includes, without limitation: - reduced air quality; - an increase in Greenhouse Gas Emissions; - dumping or destruction of stock created using Natural Capital; - wasted Embedded Carbon (e.g. scrappage of products or materials); - other comparable adverse effects, such as higher‑emission workarounds, emergency transport, flaring or unplanned waste. Key legal features are the “direct result” causal link and measurability (often by reference to agreed baselines, scopes and timeframes). Parties commonly use ACOs to trigger notice, mitigation, remediation, offsets or disclosure, and to carve out or qualify relief under Force Majeure or termination provisions. Usage and interpretation are broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland, subject to the parties’ defined terms and the contract’s governing law.