Importance of equitable cost sharing in the Convention on Biological Diversity's protected area agenda

Establishing systems of protected areas (PAs) and other effective area-based conservation measures (OECMs) is a key strategy to reversing biodiversity loss (CBD SBSTA, 2021; Maxwell et al., 2020). As part of its mandate to safeguard biodiversity, the UN Convention on Biological Diversity (CBD) provided clear international targets on establishing PAs and OECMs in 2010. Aichi Target 11 called for the protection of 10% of marine and 17% of terrestrial areas globally (CBD, 2010). These percentages were interim targets to encourage ambition while ensuring tractability and not necessarily based on conservation needs (Woodley et al. 2019). There is general consensus that the percentages behind Target 11 were insufficient to protect all important aspects of Earth's biodiversity. Proposed replacement percentages range from 28% to 80%, depending on the desired outcome (Butchart et al., 2015, Dinerstein et al. 2019, Woodley et al. 2019, Jones et al., 2020). As the CBD finalizes its post-2020 strategic plan - the Global Biodiversity Framework (GBF) - there is consensus that it must include more ambitious area-based targets paired with stronger implementation mechanisms (Visconti et al., 2019; Maxwell et al., 2020).

Most lessons learned from the outcomes of Aichi Target 11 relate to the suitability of its environmental targets, potentially obscuring how it affected social equity (the absence of avoidable and unfair cost and benefit distributions) (McDermott et al., 2013). The power to implement CBD targets lies with countries through their national biodiversity strategic and action plans (NBSAPs). Whether targets are achieved equitably depends on decision-makers within national borders. However, global conservation is inherently a transboundary pursuit; costs of environmental degradation and benefits of conservation spill over borders (Mason et al., 2020; Roberson et al., 2020). Geopolitical states have high variability in the numbers of threatened species and habitats within their borders and varied abilities to conserve based on financial capacities, conflict, and collective attitudes toward conservation. These realities require consideration of equity beyond the local scale to equity among geopolitical states in global conservation efforts (Sarkki & Garcia, 2019).

To date, the CBD has emphasized equitable benefit sharing, or the fair distribution of benefits from the harvest or study of biological resources (Nagoya Protocol). There has been less emphasis on equitable cost-sharing, which includes direct costs of establishing and managing PAs and opportunity costs of not undertaking certain economic activities (e.g., agriculture) in PAs (Naidoo & Iwamura, 2007). Costs pose significant short-term barriers to halting biodiversity loss (Waldron et al., 2013; Maxwell et al., 2020). Once adequate financing and equitable cost-sharing are achieved, long-term revenues and ecosystem services of most PAs are projected to exceed implementation and opportunity costs (Waldron et al., 2020). However, interventions are still needed to alleviate the short-term costs certain groups may bear.

Although the CBD does not legally require that countries implement equitable cost-sharing, finalization of the GBF presents an opportunity to apply social equity concepts to its revised area-based conservation strategy for just and effective implementation. We highlighted this opportunity by identifying lessons learned from Aichi Target 11 through the lens of social equity theory. We then devised recommendations on how to approach equitable cost-sharing among countries for PAs in the post-2020 GBF.