Biodiversity is the diversity of life on earth: of genes, species and ecosystems. In addition to its intrinsic value, it ­underpins the ecosystem services that sustain our lives in multiple ways. They provide food, water and medicine; ensure soil and water regulation, pollination, erosion and flood control, disease control, and carbon storage. Biodiversity is indispensable for climate change mitigation and adaptation,indispensable for climate change mitigation and adaptation and for maintaining human health. It also enhances recreational activity, creative inspiration and cultural heritage.

And yet, unprecedented economic growth and human intervention are causing biodiversity loss at equally unprecedented rates. Changes in biodiversity were more rapid in the past 50 years than at any time in human history, and are projected to continue or accelerate. The planet lost 87% of its wetlands between 1700 and 2000, 38% mangroves up to 2010, half its live coral cover since the 1870s, and one-third of its forests to date. Current species extinction rates are estimated at 100 to 1000 times higher than over the past tens of millions of years. 30% tree species are threatened with extinction. Forest fragmentation has reduced biodiversity by as much as 75% in some cases. The biodiversity of freshwater ecosystems (which includes one-third of all vertebrate species) is declining dramatically: globally, wetlands are vanishing three times faster than forests, and freshwater vertebrate populations have fallen more than twice as steeply as terrestrial or marine populations.

Global response to this crisis includes concrete commitments under the UN Convention on Biodiversity (CBD) to safeguard entire natural systems and the life-supporting services they provide. While none of its 20 Aichi Biodiversity Targets for 2020 was fully met at global level, the post-2020 global biodiversity framework adopted at COP-15 in December 2022 aims at fortified efforts and investment via four long-term goals for 2050 and 23 targets for urgent action by 2030. Biodiversity conservation includes protecting and restoring nature, as well as mitigating direct and indirect pressures on biodiversity.

Protection measures generally involve creating or expanding protected areas (PAs), i.e. clearly defined geographical spaces, recognized, dedicated and managed through legal or other effective means to achieve the long-term conservation of nature with associated ecosystem services and cultural values [CBD]. Over 120,000 designated PAs cover about 15% of terrestrial and freshwater environments and 7% of the marine realm. However they only partly cover important sites for biodiversity and are not yet fully ecologically representative and effectively or equitably managed; only an estimated 20% of PAs are being managed well. Larger and more strictly protected areas are considerably more effective for conservation. PAs need to be extended and integrated into the surrounding land and sea, involve local and indigenous communities, and have resources allocated for better management. More investment in PAs is crucial, and the funds required are small. To protect 30% of the world’s land and ocean, and manage the areas effectively by 2030 would require an estimated average investment of $140 billion annually: only 0.16% of global GDP, and less than one-third of the global government subsidies currently supporting activities that destroy nature. The benefits, even when confined to financial benefits, exceed the costs significantly.

Restoration is more complicated than protection. While it could take decades for a rainforest to tip over into a savannah, or just hours for the eutrophication of a pond, reversing the process is difficult and costly – and sometimes impossible. Rainforests that tipped over into savannahs, for instance, can never be retrieved. While avoiding the degradation of nature should take priority, much of global biodiversity lies outside PAs. Restoration measures – habitat management, rewilding, natural regeneration and sustainably productive lands and seas – also play an essential role. Modern agriculture has diminished biodiversity via intensive faming methods such as monocultures and excessive use of chemicals. Restoration can transform degraded areas to landscapes providing multiple ecosystem services, balancing provisioning with regulating services via sustainable land management, including shifting cultivation and crop rotation, and greater incentives to farmers to adopt practices supporting biodiversity and ecosystem services. Nature-based solutions (NBS) can play a key role.

The main direct drivers of biodiversity loss are changes in land and sea use, overexploitation, climate change, pollution, and invasive alien species. Agricultural intensification is an important contributor to biodiversity loss via land-use change, climate change and pollution. In addition to dedicated policies to mitigate these direct drivers, NBS, nature-friendly agriculture, and the restoration practices described above can reduce their impact. Most importantly, biodiversity needs to be mainstreamed across all productive and extractive sectors such as mining, fisheries, forestry and agriculture. Moreover, the direct drivers cannot be adequately mitigated without addressing their underlying causes or indirect drivers of biodiversity loss: unsustainable patterns of production, consumption, resource use and trade. These patterns are strongly entrenched in societal values and behaviours, and can only be mitigated through transformative change: fundamental, system-wide reorganisation across technological, economic and social factors, including paradigms, goals and values. Both direct and indirect drivers of biodiversity loss have accelerated in the past 50 years.