Five rules for scientifically credible nature markets.

Nature markets are proliferating rapidly around the world, yet it is underacknowledged that they have been practised in various forms for decades. A large body of scientific research has shown that nature markets regularly do not achieve their environmental objectives and provides generalizable lessons to support their ongoing improvement. The scale of the biodiversity crisis and the enduring popularity of nature markets mean it is now critical to stop reproducing the same mistakes. Here we synthesize international research from the history of nature markets and summarize five rules that are necessary precursors for achieving their environmental aims. We propose a checklist for investors, policymakers and civil society to assess whether nature markets are likely to be delivering scientifically credible outcomes. We score the world's largest nature markets against these rules and show that all face integrity risks. Lastly, we outline critical evidence-based actions that can be taken to push nature markets towards greater integrity.