The global trade in wildlife is a high-profile driver of species declines. It is estimated that 24% of vertebrate species are subject to this threat, and this number is expected to increase as closely related species replace those that have been driven to extreme rarity1. A meta-analysis found that wildlife trade causes an average 61.6% decline in species abundance at sites at which trade occurs, including local extirpation in 16.4% of cases2. The species affected by trade are not evenly distributed phylogenetically or geographically; the proportion is as high as 45% for birds and, overall, is strongly concentrated in the biodiverse tropics.

Although trade occurs at many levels, from local communities upwards, it is international trade that drives some of the most well-known problems and can most realistically be tackled with global agreements. CITES first arose in the 1960s, largely in response to concerns about the effects of the luxury goods trade; a final text of the treaty was agreed by 80 countries in Washington, DC on 3 March 1973. This was followed by ratification by member states, with the agreement coming into force in 1975. The vast majority of UN member states are parties to the convention: the total is now 183 countries, plus the European Union. The database of trades authorized by CITES is in itself a valuable resource for assessing changing patterns in wildlife trading more broadly3.

CITES is a legally binding agreement, but one that places the onus on member states to adopt its provisions through national laws. The 38,700 protected species are listed in one of three appendices: Appendix 1 is for species that are threatened with extinction, and for which trade is therefore effectively banned; Appendix 2 is for species that are not threatened now, but could be if trade was not regulated; and Appendix 3 is for species for which trade needs to be regulated in specific countries, but not globally. It is worth noting, however, that Scheffers et al.1 identified 4,545 traded vertebrate species from searching the IUCN Red List that were not listed on a CITES appendix as well as 723 traded species listed by CITES that do not have Red List status, so coverage is still patchy. Species are listed and potentially moved between appendices through agreement at the three-yearly conference of parties; the 2016 meeting was a particularly strong example for new listings.

CITES is one of the oldest environmental-protection agreements and has the advantage of being relatively straightforward. Although the trade in wildlife has grown and diversified in the past 50 years, CITES still has a specific focus. The proportion of nations that have implemented all of the legally binding provisions of CITES is higher than the equivalent estimate for the voluntary recommendations under the Aichi Targets of the Convention on Biological Diversity4. The Aichi Targets, and the new Global Biodiversity Framework, are multifaceted attempts to address biodiversity decline in its entirety, and are therefore fraught with complexity and competing priorities. As A. Cliquet noted in a Q&A5, CITES has had successes in a similar way to the 1987 Montreal Protocol, which has a specific focus on ozone-depleting gases.

In some senses, the strengths of CITES are also its weaknesses. Local and national trading is left to national governments, as is actually cracking down on the trade that CITES makes illegal. The mechanism is essentially a reactive one that lists species once a concern arises, with little foresight about the effects on other species of each decision. There is considerable room for political influence over which species are listed or omitted. And the level of funding for CITES — both centrally and in terms of the costs to national governments of enforcing it — are vanishingly small compared with the funding needed for biodiversity conservation overall. This both allows CITES to work and limits its influence.

However, CITES has clearly been a force for good, both as an early example of an international environmental agreement and as a specific tool to help to protect species from certain threats. The probable association of traded wildlife with the origin of the COVID-19 pandemic gives particular prominence to attempts to regulate this trade, including at an international level. CITES should therefore continue to be supported and to evolve, and should serve as an example of a workable process for a whole range of other international environmental agreements.