Key Takeaway
Species are disappearing 100 to 1,000 times faster than the natural background rate, but whether this qualifies as a "mass extinction" in the traditional sense remains scientifically contested. What is not contested is that human activity is driving unprecedented biodiversity loss — and that conservation action demonstrably works when applied at scale.
47,000+
Species Threatened
IUCN Red List 2025
73%
Wildlife Population Decline
Living Planet Index since 1970
40%
England Species Decline
Average abundance since 1970
35
Species Saved in the UK
Species Recovery Programme
Sources: IUCN Red List 2025, WWF Living Planet Report 2024, DEFRA Species Abundance Indicators 2024, UK Species Recovery Programme 2025
The phrase "sixth mass extinction" has become one of the most debated terms in modern ecology. Species are vanishing at rates between 100 and 1,000 times faster than the natural background rate of roughly 0.1 per cent per million species per year, according to analyses published in Popular Science and peer-reviewed journals. Yet fewer than 1,000 species have been formally confirmed as extinct in the past 500 years — a figure that has led some scientists to question whether "mass extinction" is the right term at all.
This article examines the evidence, separates the myths from the data, and explores what the science actually tells us about the state of life on Earth — with a particular focus on the United Kingdom, which ranks among the world's most nature-depleted countries.
To evaluate whether a sixth mass extinction is underway, it helps to understand what the previous five looked like. Each involved the loss of at least 75 per cent of species, typically driven by catastrophic environmental disruption over timescales ranging from thousands to tens of millions of years.
| Event | When | Species Lost | Primary Cause |
|---|---|---|---|
| Late Ordovician | 443 Mya | ~85% | Glaciation and ocean anoxia triggered by atmospheric CO₂ reduction |
| Late Devonian | 380–359 Mya | ~75% | Euxinic ocean conditions from terrestrial plant expansion; slowest recovery |
| Permian–Triassic | 252 Mya | ~96% | Siberian Traps volcanism drove CO₂ from 400 to 2,500 ppm; ocean acidification |
| End-Triassic | 200 Mya | ~75% | Pangaea break-up, volcanism, acid rain and carbon cycle disruption |
| Cretaceous–Palaeogene | 66 Mya | ~75% | Chicxulub asteroid impact; global photosynthesis suppression |
Source: Extinction event — Wikipedia (accessed 2026)
Every previous mass extinction shared common features: multiple environmental disruptions acting simultaneously, disproportionate losses in certain groups, and recovery timescales measured in millions of years. Recovery from the Permian–Triassic event — the "Great Dying" that eliminated 96 per cent of marine species — took roughly ten million years. These timescales are incompatible with anything resembling human civilisation.
The case for a sixth mass extinction rests on multiple independent data streams. The IUCN Red List documents more than 47,000 species threatened with extinction — 28 per cent of all assessed species. Amphibians are the most at-risk major group at 41 per cent threatened, followed by sharks and rays at 37 per cent and conifers at 34 per cent.
The 2024 Living Planet Index reported an average 73 per cent decline across tens of thousands of wildlife populations since 1970. However, this figure requires careful interpretation. Analysis by Our World in Data showed that excluding just 2.4 per cent of the most severely declining populations actually reverses the trend to show slight overall growth. The distribution of losses is highly uneven — particular species and ecosystems suffer catastrophic declines whilst others remain relatively stable.
A landmark 2011 Nature review modelled future trajectories: if all currently threatened species went extinct within 100 years and that rate continued, Earth would surpass the 75 per cent species-loss threshold within 550 years. The crisis is real, but its timescale differs fundamentally from an asteroid impact.
The Bottom Line
Documented extinctions remain far below mass extinction thresholds. What makes the current crisis alarming is not how many species have already disappeared, but how many are on a trajectory toward extinction — and the speed at which populations are declining.
Research published in 2025 in Proceedings of the Royal Society B analysed 912 documented extinctions across plants and animals over 500 years and found something unexpected: extinction rates have actually been declining for the past century, having peaked around the turn of the 20th century. For vertebrates, arthropods and plants, the rate of confirmed extinctions has generally decreased over the past 100 years.
This counterintuitive finding makes sense in context. Historically, most extinctions were concentrated on islands, driven by invasive species — rats, pigs, goats and rabbits devastating isolated fauna. Conservation efforts have been relatively effective against these threats. The danger now is that extinction drivers have fundamentally shifted: where past extinctions targeted island endemics through invasive predators, contemporary threats are habitat destruction on continents and climate change, which operate at vastly larger geographic scales and through different mechanisms.
The total number of species threatened with extinction has increased dramatically even as confirmed extinction rates have slowed — suggesting that a wave of committed extinctions is building that will not appear in the statistics for decades to come.
Background extinction is indeed a natural process, occurring at roughly 0.1 per cent per million species per year. But current rates exceed this by factors of 100 to 1,000. When extinction rates outpace speciation rates by orders of magnitude, evolutionary recovery becomes impossible on human timescales. Life survived the previous five mass extinctions — but recovery from each took millions of years.
Fewer than 1,000 confirmed extinctions in 500 years sounds modest until you consider three facts. The fossil record is inherently incomplete, meaning actual losses are underestimated. The precursor to extinction is dramatic population decline, which tens of thousands of species are currently experiencing. And the time lag between a species becoming demographically doomed and its formal extinction can stretch decades — committed extinctions simply have not appeared in the statistics yet.
The United Kingdom — a developed temperate nation with extensive legal protections — has lost roughly 40 per cent of average species abundance in England since 1970, with priority species declining by 80 per cent. Of Great Britain's 1,720 vascular plants assessed in the 2025 Red List, 26 per cent are now threatened with extinction, up from 20 per cent in 2005. Tropical and temperate ecosystems are interconnected through migratory species, ocean currents and atmospheric circulation.
Speciation typically requires millions of years. More critically, extinction is not random — it preferentially eliminates species with traits making them vulnerable to current drivers. Every species performs ecological roles: pollination, seed dispersal, predation, ecosystem services upon which both remaining species and human societies depend. Losing a keystone species can trigger cascading collapse across an entire food web.
Agricultural technology has historically been the primary driver of habitat destruction, not the solution to it. Gene editing shows promise for restoring genetic diversity in endangered species, but no technology can restore an extinct ecosystem if the habitat no longer exists. Technology is essential — but as a complement to habitat protection, never a replacement for it.
This counsel of despair contradicts the evidence. Tropical forests can regenerate within decades. The UK Species Recovery Programme has prevented at least 35 national extinctions over three decades. Rewilding projects across Britain show rapid ecosystem recovery once pressures are removed. The situation is serious — but reversible.
The UK provides a particularly instructive case study because it is a data-rich, well-regulated nation that has still experienced severe wildlife decline. The BBC has noted that Britain retains only about 50 per cent of its biodiversity compared to a global average of 75 per cent — making it one of the world's most nature-depleted countries.
Birds in Decline
Farmland bird populations have fallen 62 per cent since 1970. Turtle Dove, Tree Sparrow and Grey Partridge have each declined by over 90 per cent. Seabird populations are down 37 per cent since 1986, with 18 of 26 breeding species now threatened with UK extinction.
Freshwater Collapse
Freshwater species populations have fallen 84 per cent between 1970 and 2020 — the steepest decline of any UK habitat type. Seven of 34 assessed freshwater fish species are now classified as threatened, including European eel and Atlantic salmon.
Sources: BTO Wild Bird Indicators 2024, RSPB Marine Report 2025, DEFRA Species Abundance Indicators
The insect decline adds further concern. A 27-year German study found a 76 per cent decline in flying insect biomass in nature reserves — an average loss of 2.8 per cent per year. Climate projections suggest 14 to 27 per cent of insect species could face extinction by 2070 under moderate warming scenarios. The most affected groups are bees, butterflies, moths, beetles, dragonflies and damselflies — many of which underpin pollination and food webs that agricultural systems depend on.
The UK's global footprint matters too. Annual UK consumption of crop, cattle and timber commodities was associated with an estimated 29,000 hectares of deforestation worldwide in 2023, according to the JNCC Global Biodiversity Impact indicator. Understanding UK extinction risk means examining both local species loss and the global consequences of consumption patterns.
The causes of biodiversity loss are well documented. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) identifies five primary drivers: habitat loss, direct exploitation, climate change, pollution and invasive species.
A sophisticated 2025 analysis published in Science Advances demonstrated that only by simultaneously mitigating habitat loss, climate change and exploitation together could vertebrate population declines be reversed. Managing any single threat in isolation proved insufficient. The combination of pollution, climate change and disease produced particularly severe impacts — population declines exceeding 16 per cent annually.
Why Single-Issue Conservation Falls Short
Common assumption: Addressing one major threat — such as habitat loss or climate change — will be enough to reverse species declines.
The evidence: Research shows that biodiversity threats interact additively. Protecting habitat alone will not save species also pressured by climate change, pollution and invasive species. Effective conservation requires tackling multiple drivers simultaneously.
The UK Species Recovery Programme has prevented at least 35 national extinctions over three decades. In 2025 the government announced £60 million over three years — more than double the previous funding — plus an additional £30 million for species recovery on the national forest estate, representing the largest ever government investment in threatened species.
Rewilding successes provide the most compelling evidence that ecosystems can bounce back. Beavers, once extinct in Britain, have been reintroduced to locations across England, Scotland and Wales, with new kits spotted in 2024 in Northumberland, Kent, the Cairngorms and even London for the first time in 400 years. Their dams reduce flood effects by up to 60 per cent — an increasingly valuable ecosystem service as extreme weather intensifies.
White-tailed eagles are soaring over Britain again after 75 years of reintroduction effort. Pine martens have returned to Wales and northern England, where they help red squirrels by suppressing invasive grey squirrels. In the Scottish Borders, 25 years of rewilding has produced over 750,000 native trees and 262 recorded bird species on land previously managed for intensive grazing.
Marine protection shows equally rapid results. King scallop populations in UK no-take zones showed up to eight-fold increases in density following protection. Globally, the reintroduction of just 14 wolves to Yellowstone in 1995 triggered cascading ecological recovery — balanced deer populations allowed overgrazed areas to recover, trees rebounded, riverbanks stabilised, and beavers, eagles and foxes returned.
The Kunming-Montreal Global Biodiversity Framework commits nations to protecting at least 30 per cent of land and sea by 2030 — the "30x30" target. Currently only 5.98 per cent of UK land meets criteria for effective protection and management for nature, meaning Britain must roughly quintuple its protected area coverage to meet the target.
The UK Environment Act established legally binding targets: halt species decline by 2030, achieve a 10 per cent increase by 2042, and restore 77 per cent of water bodies to their natural state. The 2025 Environmental Improvement Plan commits to creating or restoring 250,000 hectares of wildlife-rich habitat by 2030 and doubling the number of farms providing sufficient year-round resources for wildlife.
Citizen science is emerging as a crucial force. Over 70 per cent of records used in UK biodiversity reporting are created by volunteers, according to Natural England. New technologies including environmental DNA analysis, bioacoustics and artificial intelligence are transforming the scale of evidence collection available to conservation programmes.
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Scientists disagree on the terminology, but not on the underlying crisis. Extinction rates are 100 to 1,000 times above background levels, and more than 47,000 species are threatened. Whether the 75 per cent species-loss threshold that defines a mass extinction has been reached is debatable — but projections suggest it could be crossed within centuries if current trends continue.
Current vertebrate extinction rates are estimated at 8 to 1,000 times the natural background rate, depending on methodologies used. The background rate is roughly 0.1 per cent per million species per year. The wide range reflects differences in how researchers estimate historical baseline rates and which taxa they include in their analyses.
The Living Planet Index measures the average change in population size across studied wildlife populations since 1970. The 73 per cent figure reflects average population decline, not the proportion of species that have gone extinct. The decline is driven by extreme losses in a small subset of populations — excluding just 2.4 per cent of the most severely declining populations reverses the overall trend.
The UK is one of the world's most nature-depleted countries, retaining roughly 50 per cent of its biodiversity compared to a global average of 75 per cent. Average species abundance in England has declined by 40 per cent since 1970, priority species have declined by 80 per cent, and 26 per cent of Great Britain's vascular plants are now threatened with extinction.
Yes — conservation demonstrably works when implemented at scale. The UK Species Recovery Programme has prevented at least 35 national extinctions. Rewilding projects show rapid ecosystem recovery: beavers have returned to Britain after centuries of absence, white-tailed eagles are breeding again, and marine no-take zones have increased scallop populations by up to eight-fold.
The 30x30 target, part of the Kunming-Montreal Global Biodiversity Framework, aims to protect at least 30 per cent of land and sea by 2030. Currently only 5.98 per cent of UK land meets criteria for effective protection and management for nature, meaning the UK must roughly quintuple its protected area coverage within the next few years to meet the target.
Sources: IUCN Red List 2025, Our World in Data — Living Planet Index, DEFRA Species Abundance Indicators 2024, Mongabay — Extinction Data 2025, UKCEH — GB Vascular Plant Red List 2025, Science Advances — Multiple Threats 2025, UK Environmental Improvement Plan 2025