Biodiversity loss, climate change, and pollution are inextricably connected, together constituting the triple planetary crisis. While each challenge requires dedicated responses, policy efforts should also account for interlinkages among biodiversity loss, climate change and pollution, as relevant, to maximise opportunities for synergistic action while minimising the risk of trade-offs. This brief synthesises insights from the OECD’s Environmental Outlook on the Triple Planetary Crisis to support more integrated policies for managing and expanding protected areas.
Global biodiversity is in decline, compromising essential ecosystem services that support prosperous economies, human health and well-being. Biodiversity measured in terms of terrestrial mean species abundance is projected to continue declining under current policies through to 2050.
Protected areas are a cornerstone of biodiversity conservation. They play a vital role in maintaining habitats and facilitating species movement, while maintaining ecological processes. Their importance is reflected in the target set out in the Kunming-Montreal Global Biodiversity Framework to conserve at least 30% of terrestrial, inland water, coastal and marine areas by 2030. While four years remain before the target date, current coverage falls short.
Protected areas can help tackle the triple planetary crisis, but further work is needed to support integrated policy approaches. The benefits of protected areas extend well beyond biodiversity conservation, contributing to climate mitigation and adaptation as well as to cleaner water, air and soil. Despite the potential for synergies, however, protected areas themselves are vulnerable to climate change and pollution. Accounting for these interactions when designing and managing protected areas can help ensure they remain fit for purpose as environmental conditions evolve.
Policymakers can use several approaches and tools to harness the potential of protected areas in delivering synergies while minimising the risk of trade-offs. These can include: (i) mainstreaming protected areas across different policy domains, (ii) leveraging spatial planning and strategic environmental assessment, (iii) promoting co-ordination across levels of government, (iv) monitoring emerging risks on established sites and applying adaptive managing approaches and (v) deploying economic instruments to sustain effective management and facilitate alignment of incentives.
Protected areas in a changing environment
Biodiversity is critical for prosperous economies and resilient societies, providing essential ecosystem services, ranging from pollination to water purification and climate regulation. Despite its importance, many of nature’s benefits continue to be undervalued, and biodiversity is in decline globally. The latest Global Assessment by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) suggests that around one-quarter of species in assessed animal and plant groups are already threatened with extinction (IPBES, 2019[1]). Biodiversity decline, in turn, compromises valuable and often irreplaceable ecosystem services, such as animal pollination, on which approximately 75% of global food crop types rely to some extent (IPBES, 2016[2]).
Without further action, the species extinction rate – which is, “already at least tens to hundreds of times higher than it has averaged over the past 10 million years” – will further accelerate (IPBES, 2019, p. 12[1]). Under current policies, OECD projections provided in its latest Environmental Outlook suggest that biodiversity will continue to decline globally between 2020 and 2050, with the terrestrial mean species abundance index dropping from 59.7 to 56.5 (OECD, 2025[3]).
Importantly, species and ecosystems do not exist in isolation but interact with other environmental challenges. Illustratively, biodiversity loss together with climate change and pollution form the triple planetary crisis. These challenges are inextricably connected and interact in complex ways. For example, climate change and pollution each account for around 14% of the impact of direct anthropogenic drivers of biodiversity loss, while land and sea-use changes (30%) as well as direct exploitation of natural resources (23%) remain the dominant drivers today (IPBES, 2019[1]). Under current policies, OECD projections suggest that climate change is set to become the dominant driver of biodiversity loss by 2050.
Interlinkages among the dimensions of the triple planetary crisis have been recognised by multilateral frameworks. For instance, the Kunming-Montreal Global Biodiversity Framework, adopted by the Parties to the Convention of Biological Diversity in 2022, includes targets to “reduce pollution to levels that are not harmful to biodiversity” (Target 7) and to “minimize the impacts of climate change on biodiversity and build resilience” (Target 8). Yet the challenge remains in translating the recognition of these interlinkages into more integrated policy action. A stocktake of national documents submitted under multilateral frameworks across ten diverse countries suggests that countries only partially recognise the interconnected nature of climate change, biodiversity loss and pollution (OECD, 2025[3]). While addressing individual challenges through dedicated policy responses remains critical, siloed approaches at the policy planning and implementation level can lead to missed opportunities for synergies and face challenges in terms of their effectiveness, as a core response to one dimension of the triple planetary crisis may risk trade-offs with the other two.
Protected areas and other effective area-based conservation measures1 help halt and reverse biodiversity loss. Protecting biodiversity – specialised and narrowly distributed species in particular – requires large areas of intact environments. By restricting or managing activities that place pressure on species and ecosystems, protected areas can help maintain key habitats and ecological processes and provide refuges for threatened species as part of a broader policy mix. Available evidence suggests that global biodiversity loss would have been even greater in the absence of protected areas.
While protected areas are not costless and can entail opportunity costs for restricted economic activities, well-designed and effectively managed protected areas can generate ecological and economic benefits. For instance, well-designed marine protected areas can help to reduce pressures from overfishing and enhance fish stocks. Robust assessments of costs and benefits can help ensure that protected areas are strategically sited to maximise conservation outcomes while enhancing cost-effectiveness (OECD, 2017[4]).
The importance of protected areas is reflected in Target 3 of the Kunming-Montreal Global Biodiversity Framework. The target calls for at least 30% of terrestrial and inland water areas and at least 30% of marine and coastal areas to be effectively conserved and managed by 2030 through ecologically representative, well-connected and equitably governed systems of protected areas and other effective area-based conservation measures. Although notable progress has been made, a sizeable gap to the 2030 target remains: protected areas and other effective area-based conservation measures currently cover around 19% of land (terrestrial and inland water areas) and 10% of the ocean (marine and coastal areas) (UNEP-WCMC and IUCN, 2026[5]).
While protected areas are primarily designed to halt and reverse biodiversity loss, they can contribute to wider climate and pollution objectives. Their role in carbon storage, for instance, is estimated to be substantial. Globally, protected areas and other effective area-based conservation measures contain an estimated 25% of aboveground biomass, 21% of belowground biomass, 15% of soil organic carbon and 7% of carbon stored in marine sediments (UNDP, SCBD and UNEP-WCMC, 2021[6]). Similarly, protected areas can help filter pollutants, supporting cleaner water, air and soil. For instance, protected areas contribute to the availability of freshwater downstream, while the water they provide tends to be exposed to lower levels of threat, including from pollution (Harrison et al., 2016[7]).
Despite the potential for synergies, protected areas themselves remain vulnerable to climate change and pollution. Climate change can shift the distribution of species as they move in search of more suitable habitats, potentially making areas designated around their original distribution less aligned with changing conservation needs. Further, protected areas remain vulnerable to pollution originating within, upstream from or adjacent to their boundaries. Agricultural fertilisers, pesticides, heavy metals, animal waste and sewage can threaten air, soil, and water quality, while also directly affecting protected flora and fauna.
Integrating climate change and pollution considerations into protected area design and management is therefore critical to ensure they remain fit-for-purpose as environmental conditions evolve. Expanding and improving protected areas – including through ensuring they are well-connected, as envisaged under the Kunming-Montreal Global Biodiversity Framework target – represents an important opportunity to strengthen biodiversity conservation. However, if protected areas are designed without accounting for climate change and pollution, there is a risk that they will be progressively less able to deliver on their conservation objectives.
In this context, robust monitoring, periodic assessments and adaptive management provide a framework for ensuring protected areas remain fit for purpose (Figure 1). This entails an iterative process of: (i) assessing vulnerability to climate change and pollution; (ii) implementing targeted management and adaptation measures; and (iii) monitoring outcomes to adjust action as conditions and evidence evolve. Tracking biodiversity, environmental pressures, management responses and ecosystem services – including impacts beyond protected area boundaries – can also provide an evidence base for identifying emerging risks.
In addition to adapting protected areas to climate change and pollution, it is also essential to tackle climate change and pollution at source, including by addressing their underlying drivers such as unsustainable patterns of food, resource and energy production and consumption. Efforts to address these drivers can, however, create tensions between different environmental objectives due to competing demands for land and sea use. The expansion of renewable energy illustrates the need to navigate this complex challenge. Rapid deployment of renewable energy helps reduce greenhouse gas emissions and alleviate climate-induced pressures on species and ecosystems. Yet, if not carefully planned, renewable energy infrastructure such as solar photovoltaics and wind turbines can have significant spatial footprints, risk fragmenting natural habitats and pose complex waste management challenges at the end of their lifecycle. As countries simultaneously scale up renewable energy and protected areas, ensuring that these projects are strategically sited and designed is therefore critical to achieving positive outcomes for both climate and nature (OECD, 2024[10]).
The effectiveness of protected areas – today and in the future – will depend on several factors, including which areas are selected, how they connect with existing protected area networks and how effectively they are managed and adapt to the changing environment. Several tools and approaches can bring these considerations together to develop more integrated policies to tackle the triple planetary crisis.
Mainstreaming protected area management across policy domains can help align environmental objectives. National planning offers an important entry point. Strategies for expanding and managing protected areas can be reflected across a range of national planning and reporting documents, including National Adaptation Plans, Nationally Determined Contributions and sectoral strategies, harnessing their whole-of-government reach to identify opportunities for more integrated policy action.
Spatial planning and strategic environmental assessments can translate integrated approaches into informed decisions about where and how protected areas are designated and managed in practice. These tools together with consideration of costs and benefits can help manage competing demands for land and sea, identify areas offering multiple benefits (e.g. high conservation value and carbon storage), strengthen ecological connectivity through network-level planning, and embed protected areas within broader networks of sustainably managed lands and waters.
Vertical co-ordination can connect tailored site-level management with actions across levels of governance. Local management can respond to conditions within individual protected areas, while regional and national action can address pressures extending beyond their boundaries or beyond the remit of site managers, including upstream pollution, infrastructure development and gaps in ecological connectivity.
Assessments of exposure and vulnerability of protected areas to climate change and pollution can facilitate their adaptative management. Robust monitoring of biodiversity outcomes, environmental pressures and ecosystem services can help assess where interventions are needed and facilitate the implementation of early targeted responses.
Economic instruments can help put effective protected area management on a stronger financial footing while offering ways to align economic incentives with wider environmental objectives. Instruments such as fees and payments for ecosystem services can mobilise resources for conservation and reward sustainable management of nature. More broadly, well-designed economic incentives can also help avoid a dichotomy between protected and non-protected areas, ensuring environmental pressures are reduced rather than simply displaced elsewhere.
OECD (2025), Environmental Outlook on the Triple Planetary Crisis: Stakes, Evolution and Policy Linkages, OECD Environmental Outlook, OECD Publishing, Paris, https://doi.org/10.1787/257ffbb6-en.
OECD (2025), Scaling Up Biodiversity-Positive Incentives: Delivering on Target 18 of the Global Biodiversity Framework, OECD Publishing, Paris, https://doi.org/10.1787/19b859ce-en.
OECD (2024), Mainstreaming Biodiversity into Renewable Power Infrastructure, OECD Publishing, Paris, https://doi.org/10.1787/357ac474-en.
OECD (2017), Marine Protected Areas: Economics, Management and Effective Policy Mixes, OECD Publishing, Paris, https://doi.org/10.1787/9789264276208-en.
References
[12] Convention on Biological Diversity (2018), Decision adopted by the conference of the parties to the convention on biological biodiversity 14/8. Protected areas and other effective area-based conservation measures.
[9] Coudurier, C., L. Petit and A. Tissot (2023), Démarche d’adaptation au changement climatique Natur’Adapt - Guide méthodologique d’élaboration d’un diagnostic de vulnerabilité et d’opportunité et d’un plan d’adaptation à l’échelle d’une aire protégée, LIFE Natur’Adapt - Réserves Naturelles de France.
[11] Dudley, N. (ed.) (2008), Guidelines for Applying Protected Area Management Categories, IUCN.
[8] Gross, J. et al. (eds.) (2017), Adapting to Climate Change: Guidance for protected area managers and planners, IUCN International Union for Conservation of Nature, https://doi.org/10.2305/iucn.ch.2017.pag.24.en.
[7] Harrison, I. et al. (2016), “Protected areas and freshwater provisioning: a global assessment of freshwater provision, threats and management strategies to support human water security”, Aquatic Conservation: Marine and Freshwater Ecosystems, Vol. 26/S1, pp. 103-120, https://doi.org/10.1002/aqc.2652.
[1] IPBES (2019), Summary for policymakers of the global assessment report on biodiversity and ecosystem services (Version summary for policy makers), IPBES Plenary at its seventh session (IPBES 7, Paris, 2019), https://doi.org/10.5281/zenodo.3553579.
[2] IPBES (2016), The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production, Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.
[3] OECD (2025), Environmental Outlook on the Triple Planetary Crisis: Stakes, Evolution and Policy Linkages, OECD Environmental Outlook, OECD Publishing, Paris, https://doi.org/10.1787/257ffbb6-en.
[13] OECD (2025), Scaling Up Biodiversity-Positive Incentives: Delivering on Target 18 of the Global Biodiversity Framework, OECD Publishing, https://doi.org/10.1787/19b859ce-en.
[10] OECD (2024), Mainstreaming Biodiversity into Renewable Power Infrastructure, OECD Publishing, Paris, https://doi.org/10.1787/357ac474-en.
[4] OECD (2017), Marine Protected Areas: Economics, Management and Effective Policy Mixes, OECD Publishing, Paris, https://doi.org/10.1787/9789264276208-en.
[6] UNDP, SCBD and UNEP-WCMC (2021), Creating a Nature-Positive Future: The contribution of protected areas and other effective area-based conservation measures, UNDP.
[5] UNEP-WCMC and IUCN (2026), Protected Planet, https://www.protectedplanet.net/en.
Contact
Shardul Agrawala, Head of the Environment and Economy Integration Division, Shardul.Agrawala@oecd.org
← 1. Protected areas are “a clearly defined geographical space, recognised, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values” (Dudley, 2008[11]). Other effective area-based conservation measures were formally defined through the Convention on Biological Diversity Decision 14/8 in 2018; they are distinct from traditional protected areas but governed and managed in ways that achieve positive and sustained long-term outcomes for the in-situ conservation of biodiversity, with associated ecosystem functions and services and, where applicable, cultural, spiritual, socio-economic, and other locally relevant values (Convention on Biological Diversity, 2018[12]).