The sixth mass extinction is the term for a human-driven, unusually rapid global loss of species and ecosystems. It is not a single future event: extinction risk and population declines are already widespread, although scientists debate exactly whether the formal threshold for a “mass extinction” has yet been crossed.enb.iisd+1
Earth has experienced five widely recognized mass extinctions over roughly the last half-billion years, each involving the loss of a very large fraction of species in geologically short periods. The sixth-extinction framing argues that today’s losses are occurring far faster than normal background extinction rates and are principally caused by human activity.un+1
An important distinction: extinction means a species is globally gone; biodiversity loss also includes shrinking populations, lost genetic diversity, degraded habitats, and ecosystems that no longer function well. A species can therefore be in serious trouble long before its final extinction.enb.iisd
IPBES’s landmark global assessment estimated that about 1 million animal and plant species were threatened with extinction, many within decades, unless pressures are reduced. It also reported that the average abundance of native species in major land habitats had fallen by at least 20 percent, mostly since 1900.un+1
The IUCN Red List is the principal species-by-species risk database, but it has assessed only a portion of all described species—so its totals are not a complete census of life. Its recent figures show especially high risk among reef-building corals, amphibians, trees, sharks and rays, and conifers.iucnredlist+1
The five direct global drivers identified by IPBES are:
Land- and sea-use change: conversion and fragmentation of forests, wetlands, grasslands, reefs, and seabeds for agriculture, development, roads, extraction, and infrastructure.nature+1
Direct exploitation: overfishing, hunting, logging, wildlife trade, and unsustainable harvest of plants and animals.ipbes+1
Climate change: heat, drought, wildfire, ocean warming, sea-level rise, disrupted seasonal cycles, and ocean acidification push species beyond their limits.nature
Pollution: pesticides, nutrient runoff, plastics, toxic chemicals, and air pollution damage organisms and habitats, especially freshwater and marine systems.ipbes+1
Invasive non-native species: introduced organisms, pathogens, and predators can outcompete, prey on, or infect native species.nature
These do not operate separately. For example, habitat fragmentation can prevent a species from relocating as the climate warms, while pollution and warming together can make a river or reef less habitable.
Biodiversity is not only about rare or charismatic species. Healthy ecosystems help provide pollination, fertile soil, cleaner water, fisheries, flood buffering, climate regulation, disease regulation, materials, and cultural and recreational value. IPBES warns that the accelerating decline of nature has serious consequences for food, water, health, and livelihoods.enb.iisd+1
The loss of a species can also trigger knock-on effects. Losing predators can reshape food webs; losing pollinators can reduce reproduction in wild plants and crops; and losing wetlands can increase flood risk and reduce water filtration.
Anthropocene is a useful term for the period in which human activity has become a dominant force altering climate, landscapes, oceans, biological communities, and even Earth’s sediments. The sixth-extinction idea is one major biological signature of that human impact.anthroecology
However, “Anthropocene” is not currently an official geological epoch in the formal Geological Time Scale. In March 2024, the relevant geological bodies rejected a proposal to formalize it as a new epoch; the term remains widely used in science, policy, and the humanities as a description of an ongoing planetary-scale human influence.anthropocene.univie+1
No. Extinction is irreversible, but much biodiversity loss is still preventable, and depleted ecosystems can often recover when pressures decline. The core response is “transformative change”: protect and reconnect habitats, restore damaged ecosystems, reduce emissions and pollution, manage fisheries/forests/wildlife harvest sustainably, prevent invasive-species spread, and change food and consumption systems that drive land conversion.science.house+1
Conservation works most reliably when it is not limited to isolated reserves: it also needs ecological corridors, Indigenous and local stewardship, enforcement, monitoring, and production systems that use less land and cause less pollution.
This is a local issue as well as a global one. Connecticut’s 2025–2035 Wildlife Action Plan identifies species of greatest conservation need, priority habitats, threats, and conservation actions; statewide concerns include habitat deterioration and development, climate change, pollution, and invasive species.ct+1
Useful actions near Bridgeport include supporting habitat restoration and land protection, keeping cats indoors, planting locally native species, avoiding pesticide overuse, reducing outdoor light at night during bird migration, not releasing pets or aquarium species, and supporting organizations and public policies that protect Long Island Sound, wetlands, forests, and connected wildlife habitat. Connecticut’s plan specifically emphasizes land protection, vegetation management, habitat restoration, enforcement, and monitoring.ct+1