The sixth extinction—also called the Anthropocene extinction—is the unusually rapid, human-driven loss of species and populations now under way. It is not yet certain that the planet has crossed the formal paleontological threshold for a completed “mass extinction,” but extinction rates are far above long-term background levels, and roughly one million species are estimated to face extinction, many within decades without major action.un+1
A mass extinction is a geologically brief interval in which an exceptionally large share of species disappears worldwide. Earth has experienced five widely recognized previous mass extinctions over the last roughly half-billion years; the most familiar is the event about 66 million years ago associated with the end of non-avian dinosaurs.pubmed.ncbi.nlm.nih
Extinction is only the final stage. Long before a species vanishes globally, its populations may become small, fragmented, and genetically impoverished, reducing the ecosystem functions it once provided—such as pollination, seed dispersal, water purification, soil formation, and pest control.iucnredlist+1
The distinction is morally and politically important: an asteroid cannot alter its behavior, but human institutions can change energy systems, farming, fishing, trade, land use, and conservation policy.evolution.berkeley
The process did not begin all at once. Humans have altered ecosystems for millennia through hunting, burning, and agricultural expansion, but the pace and scale grew enormously through colonial expansion, industrial fossil-fuel use, intensive agriculture, global trade, urbanization, and mass extraction of wildlife and marine life.un+1
The pressures compound one another:
Habitat loss and fragmentation: Forests, wetlands, grasslands, rivers, and coasts are converted or divided by farms, roads, dams, mining, and cities; globally, land- and sea-use change is the largest direct driver of biodiversity loss.un
Overexploitation: Fishing, hunting, logging, wildlife trade, and collection can remove organisms faster than their populations can recover.un
Climate disruption: Warming, drought, fires, heat waves, shifting seasons, sea-level rise, and ocean acidification can outpace species’ ability to migrate or adapt.un
Pollution: Pesticides, nutrient runoff, plastics, industrial chemicals, and air pollution damage organisms and food webs.un
Invasive species and disease: Global transport moves species into ecosystems where they may have few natural controls; invasive alien species have been a factor in 60 percent of recorded animal and plant extinctions.invasivespeciescentre
These drivers create feedback loops. For example, clearing a tropical forest releases carbon and destroys habitat, which worsens climate change and leaves the remaining forest more vulnerable to drought and fire.unfoundation
The crisis is global, but it is uneven. Areas of high endemism—places with species found nowhere else—are especially vulnerable because a single development project, disease, storm, or invasive predator can erase an entire species. Island ecosystems therefore experience exceptionally severe losses.pubmed.ncbi.nlm.nih
Particularly exposed systems include:
Tropical forests: They hold extraordinary biodiversity but are pressured by agricultural conversion, logging, roads, mining, and climate-linked drought and fire.un
Freshwater ecosystems: Rivers, lakes, and wetlands are affected by dams, water withdrawal, pollution, invasive organisms, and warming; biodiversity can decline even when a landscape still looks “green.”un
Coral reefs: Ocean heat causes bleaching, while acidification weakens calcifying organisms; climate change is identified by NOAA as the biggest threat to reefs worldwide.coast.noaa
Polar, mountain, and coastal habitats: Species adapted to narrow temperature ranges or fixed geographic zones have little room to move as conditions shift.un
Farmland and urban margins: Pollinators, birds, amphibians, insects, and soil organisms are affected by habitat simplification, pesticides, lighting, and pollution.science.house+1
Humans are unlikely to disappear in the same immediate sense as a species with a tiny range, but human societies depend on the stability and diversity of ecosystems. Biodiversity loss therefore becomes a public-health, food-security, economic, and justice issue.un+1
Likely impacts include:
Food insecurity: Fewer pollinators, depleted fisheries, degraded soils, and lost crop diversity make food systems less productive and less resilient to drought, pests, and disease.un+1
Water and disaster risks: Wetlands, forests, mangroves, and reefs buffer floods, storms, erosion, and water contamination; their decline raises costs and exposure for communities.unfoundation
Health threats: Ecological disruption can change the distribution of disease vectors and reduce access to potential medicines derived from biological diversity.iucnredlist
Climate instability: Intact forests, peatlands, grasslands, and oceans store carbon; degrading them weakens a major natural buffer against warming.unfoundation
Widening inequality: Communities most dependent on local fisheries, forests, subsistence agriculture, and coastal protection often have the least capacity to absorb ecological losses.un
There is no single fix, but the main drivers are known and preventable. The most effective response is to reduce the pressures while restoring ecosystems and protecting the people who steward them.un+1
Protect, connect, and restore habitats. Expand well-managed protected and conserved areas; restore wetlands, forests, prairies, reefs, and river systems; and build wildlife corridors between fragmented habitats.evolution.berkeley
Rapidly cut greenhouse-gas emissions. Replacing fossil fuels with low-carbon energy, improving efficiency, and protecting carbon-rich ecosystems limits warming and ocean acidification.un+1
Reform food systems. Reduce deforestation-driven commodity production, improve soil and water management, curb excess fertilizer and pesticide use, protect agrobiodiversity, and reduce food waste. Land-use change is presently the largest global direct driver of nature loss.un
Manage fishing, hunting, logging, and wildlife trade sustainably. Set and enforce science-based limits, end illegal exploitation, and protect breeding and nursery habitats.un
Prevent and control invasive species. Stronger biosecurity, inspection, early detection, and rapid eradication or containment are generally far cheaper than managing established invasions.invasivespeciescentre
Treat biodiversity as infrastructure. Governments, firms, and communities should account for ecological costs in land-use decisions, finance restoration, and support Indigenous and local stewardship rather than viewing nature as an expendable externality.iucnredlist+1
At the personal level, the highest-leverage actions are also civic: support climate and conservation policy, reduce waste and high-impact consumption where feasible, avoid releasing pets or plants into the wild, choose responsibly sourced seafood, and participate in local habitat restoration. Individual choices matter most when paired with institutional changes equal to the scale of the problem.evolution.berkeley+1