New research shows species extinctions may have peaked 100 years ago, but scientists warn against optimism

A groundbreaking study is challenging the common belief that Earth’s sixth mass extinction is accelerating, revealing instead that species loss may have actually slowed down over the past century. However, researchers caution that this apparent good news might be misleading.

University of Arizona scientists Kristen Saban and John Wiens analyzed 912 documented extinctions spanning 500 years of history, examining data from nearly two million assessed plant and animal species. Their findings, published in Proceedings of the Royal Society B, show that extinction rates climbed dramatically through the 1800s and early 1900s before beginning to decline. Across vertebrates, arthropods, and plants, fewer species have been recorded as going extinct in recent decades compared to a century ago.

But before celebrating, scientists emphasize that this trend likely reflects gaps in our knowledge rather than genuine recovery. Most historical extinctions occurred on islands, where invasive species like rats, pigs, and goats wiped out native wildlife in dramatic, easily observable ways. Today’s primary threats—deforestation, pollution, and climate change—are devastating continental ecosystems in ways that are harder to document and may take longer to fully manifest.

The research highlights a crucial blind spot in extinction science: we may be missing ongoing losses simply because they’re happening in places we’re not looking closely enough, or because species are declining so gradually that extinctions haven’t been formally confirmed yet. While the data suggests a slowdown in recorded extinctions, the underlying pressures on global biodiversity continue to intensify, meaning the sixth mass extinction may still be unfolding before our eyes.