Species are vanishing 100 to 1,000 times faster than nature's usual pace
Extinction is normal; species have always come and gone at a slow background rate. What biologists call the Holocene extinction is different. Today's losses are estimated to run 100 to 1,000 times faster than that baseline, and most scientists agree the chief cause is human activity.
The event goes by several names: the Holocene or Anthropocene extinction, and sometimes the sixth extinction, although that label has also been applied to a much older crisis, the Capitanian. It reaches every group of living things, from mammals and birds to fish, insects and plants, on land and at sea, and on every continent. When it began is still argued over, including whether it should be separated from the Late Pleistocene die-offs that closed the last ice age, which humans probably helped along.
Island faunas show how little pressure it can take. Researchers think even light hunting was enough to erase whole species of big, exposed island animals in places such as New Zealand and Madagascar. Plants suffered heavy losses only in more recent times, as forests were cleared and land converted; ecologist Stuart Pimm estimates plant extinction now runs 100 times above normal. Modern drivers include climate change, draining wetlands, overfishing, ocean acidification and the appetite for land and resources that comes with growing populations and consumption.
Whether this already counts as a true mass extinction, defined as losing at least 75 percent of species in a geologically short span, is disputed. Barnosky and colleagues wrote in 2011 that the losses are dramatic and serious but not yet comparable to the Big Five, while noting that gaps in the fossil record make past rates hard to pin down. Estimates of species lost each year range enormously, from 1.5 to 40,000.
The warnings have grown sharper. E. O. Wilson predicted in 2002 that half of Earth's higher life forms could be gone by 2100 if trends continued. A 2021 study found only about 3 percent of the land surface still ecologically intact, and the UN's 2019 biodiversity assessment put roughly one million species at risk within decades. A 2022 survey of more than 3,000 experts estimated that around 30 percent of species have been threatened or wiped out since 1500.
Source: Holocene extinction
