Fair division for avoidance of biodiversity impacts.

Biodiversity is declining at alarming rates, with some negative impacts caused by activities that are necessary for meeting basic human needs and others which should be avoided to prevent ecological collapse. Avoidance of biodiversity impacts is costly; these costs must be distributed fairly. Principles of fair allocation - which are grounded in longstanding theories of justice and are mathematically operationalizable - are rarely used in biodiversity decision-making but can help to deliver procedural and distributive justice alongside biodiversity outcomes. We show how incorporating rules of fair allocation into biodiversity decision-making could advance policy formulation towards a safe and just future. Such rules provide a means to operationalize equity and create space for cooperatively and constructively negotiating avoidance liabilities within biodiversity impact mitigation.