Overview: A Landmark Year for Biodiversity

The 12-month period from February 2025 to February 2026 was one of the most consequential in IUCN’s history.

Against a backdrop of rapidly accelerating species loss, ocean degradation, and the continuing triple planetary crisis of climate change, biodiversity decline, and pollution, IUCN published two landmark Red List updates, played a central role at the Third United Nations Ocean Conference (UNOC 3) in Nice (June 2025) and convened the IUCN World Conservation Congress in Abu Dhabi (October 9 to 15, 2025), the world’s largest and inclusive biodiversity summit, held every four years.

The Congress assembled under the theme “Powering Transformative Conservation.” Members adopted a landmark 20-year Strategic Vision (“Unite for Nature on the Path to 2045”), a new IUCN Programme 2026–2029, and the Abu Dhabi Call to Action on Species Conservation, positioning biodiversity protection as the centrepiece of the global response to the triple planetary crisis of climate change, biodiversity loss, and pollution. Taken together, these events produced a clearer, more sobering picture of the global biodiversity emergency than at any previous point, alongside the most ambitious governance framework IUCN has ever adopted.

The data confirm that approximately 28% of all species ever assessed by IUCN across all groups from corals to fungi to birds now face extinction. Yet the Red List also carries a message of hope: IUCN’s 2025-2 update demonstrated that without conservation intervention, extinction rates for birds and mammals over the past 30 years would have been up to four times higher. Conservation works. The challenge is to scale it equitably and rapidly enough to avert the biodiversity tipping points now visible across multiple ecosystems simultaneously (IUCN, 2025c).

Key Global Biodiversity Issues Tackled by IUCN (2024–2025)

1. Coral Reef Crisis: 44% of Reef-Building Corals Now Threatened

At COP29 in Baku (November 2024), IUCN published the most comprehensive coral reassessment in 16 years, finding that 44% of all reef-building coral species globally are now threatened with extinction – up sharply from one third in 2008. The primary driver is ocean warming and bleaching, intensified by the ongoing fourth global coral bleaching event declared in 2024, which affected reefs across the Indo-Pacific, Atlantic, and Indian Oceans simultaneously. Atlantic coral species are particularly severely threatened, with annual severe bleaching events, pollution, and disease compounding thermal stress.

IUCN reiterated the finding that keeping global warming below 1.5°C is the single most important intervention for coral survival. IUCN also called for the expansion of Marine Protected Areas (MPAs) with thermal refugia characteristics as a complementary adaptation strategy, alongside accelerated fossil fuel phase-out.

2. Tree Extinction: 38% of the World’s Trees at Risk – First Global Assessment

October 2024 brought the publication of the first Global Tree Assessment, jointly led by Botanic Gardens Conservation International (BGCI) and the IUCN SSC Global Tree Specialist Group, involving over 1,000 experts. The assessment found that at least 16,425 of 47,282 assessed tree species (38%) are at risk of extinction, with threatened tree species now outnumbering all threatened birds, mammals, reptiles, and amphibians combined. The significance of this finding extends far beyond aesthetics: trees provide the structural and functional scaffolding of terrestrial ecosystems, regulating carbon storage, water cycling, soil stabilisation, microclimate buffering, and habitat provision for most terrestrial species.

The highest concentrations of threatened trees are on islands, where deforestation, invasive species, urban development, and climate-driven sea-level rise converge. South America, home to the greatest tree diversity on Earth, had 3,356 of 13,668 assessed species (24.5%) at risk, with most threats attributable to agricultural expansion (particularly for soya and cattle) and selective logging. IUCN identified seed banking, botanic garden conservation, and community stewardship as critical ex-situ safeguards while habitat protection and restoration are scaled up.

3. Bird Declines: More Than Half of All Bird Species Now in Decline

The IUCN Red List 2025-2 update revealed that more than half of all bird species globally are now in decline — a finding confirmed by BirdLife International, IUCN’s official Red List Authority for birds. The 2024 Red List saw 25 bird species uplisted to higher threat categories, including 16 migratory shorebird species whose global populations have declined by more than a third in recent decades, with rates of decline accelerating in several cases. Five species were reclassified as Extinct, including four Hawaiian honeycreepers.

Agriculture (impacting 73% of threatened bird species), logging (50%), invasive alien species (43%), and climate change (37%) were identified as the dominant drivers of bird population decline. The 2025-2 update additionally added nearly 100 threatened European bee species to the Red List, and revealed that threatened European butterfly species increased by 76% over the last decade, underscoring the severity of pollinator collapse.

4. Arctic Seal and Freshwater Species Under Escalating Threat

The 2025-2 Red List update documented that three Arctic seal species have moved closer to extinction, directly attributable to sea ice loss driven by climate change – a finding that reinforces the IUCN Arctic Biodiversity Assessment’s warnings about the disproportionate rate of warming in polar regions. Simultaneously, IUCN and partners have elevated the crisis of freshwater biodiversity: one in three freshwater fish species is now threatened with extinction globally, with water extraction, pollution, damming, invasive species, and climate-driven drought and flooding converging to degrade freshwater ecosystems faster than any other biome.

IUCN’s 2025 Congress elevated freshwater biodiversity protection as a specific programmatic priority, with measurable targets for the 2026–2029 IUCN Programme period and celebrated the release of juvenile Danube sturgeons in Europe as a tangible recovery milestone (IUCN, 2025a; 2025c).

5. Fungi: An Overlooked Kingdom in Crisis

The IUCN Red List 2025-1 update broke new ground by surpassing 1,000 fungal species assessed – an important milestone given that fungi represent an estimated 2.5 million species on Earth, yet have been almost entirely absent from global conservation monitoring. Of 1,300 fungi now assessed, at least 411 are at risk of extinction. The dominant threats are deforestation (putting 198 species at risk), agricultural and urban land conversion (threatening 279 species), and changing fire patterns in the United States, which have radically restructured forest habitats.

IUCN Director General, Dr Grethel Aguilar, described fungi as “the unsung heroes of life on Earth” whose underground networks underpin ecosystem resilience, carbon storage in soil, and agricultural productivity. Their loss represents an invisible but potentially catastrophic degradation of the ecological foundations on which all life depends.

The 2025 IUCN World Conservation Congress: Key Outcomes

The 2025 Congress in Abu Dhabi (October 9 to 15) was described by IUCN as the most action-oriented in the organisation’s history, uniting over 10,000 participants from governments, scientific institutions, Indigenous communities, businesses, and civil society under the theme “Powering Transformative Conservation.” The Congress adopted close to 150 binding motions covering biodiversity, climate, health, ecocide, plastic pollution, and ocean governance.

The Abu Dhabi Call to Action formally declared that “humanity has reached a critical point,” with nature facing escalating, converging crises from climate change, degradation, biodiversity loss, pollution, and inequity. The IUCN Programme 2026–2029 sets actionable, outcome-focused targets to guide all Union components toward measurable biodiversity impact, five years ahead of the 2030 GBF deadline.

One of the most significant findings presented at the Congress was the positive conservation evidence: the latest Red List data demonstrated that without active conservation over the past 30 years, extinction rates for birds and mammals would have been up to four times higher. The IUCN Green Status of Species assessment for tigers found that, while global tiger populations remain critically depleted relative to historical baselines, intensive conservation investment has demonstrably slowed the rate of depletion, evidence of a concept for what sustained, science-based conservation can achieve.

Critically, the Congress positioned the One Health framework — recognising the inseparability of human, animal, and ecosystem health – as a guiding principle for conservation action, citing the 2024 joint IUCN–WHO report on Nature-Based Solutions and pandemic prevention. The High Seas Treaty (Biodiversity Beyond National Jurisdiction, BBNJ) and the 30×30 protection target were reaffirmed as non-negotiable milestones for marine biodiversity governance.

Looking Ahead: Priorities for 2026

• COP30, Belém (November 2026): IUCN will be a central voice at the UN Climate Conference in Brazil, pushing for Nature-Based Solutions (NbS), biodiversity-climate co-benefits, and acceleration of the GBF 30×30 milestones ahead of the 2030 deadline.

• High Seas Treaty Entry into Force: With 50 ratifications achieved by July 2025 and entry into force at 60, the first high seas Marine Protected Areas could be designated within 2026 – the first time in history that fully protected areas have existed beyond national waters covering 61% of the ocean.

• Fungi Assessment Scale-Up: IUCN has committed to accelerating fungal Red List assessments toward a target of 5,000 assessed species by 2030, with dedicated funding secured through the IUCN Programme 2026–2029.

• Freshwater Biodiversity Emergency: IUCN’s 2026–2029 programme specifically targets freshwater systems, with new partnerships targeting restoration of 30% of degraded freshwater habitats aligned to GBF Target 2.

• GBF Midpoint Review (2025–2026): The Kunming-Montreal GBF is approaching its first formal progress review cycle; IUCN Red List and STAR metrics will serve as the primary scientific evidence base for assessing whether nations are on track to halt and reverse biodiversity loss.

By Okali Kelechi David, Programme Officer, Monitoring and Evaluation, Nigerian Environmental Study Action Team (NEST), Ibadan