Extinctions Are Slowing, Not Speeding Toward Mass Catastrophe After All

TUCSON, Ariz. — For decades, we’ve heard warnings that humanity is teetering on the edge of a new “mass extinction.” Some scientists have even suggested that the unraveling of ecosystems could threaten the survival of civilization itself. But a new study in PLOS Biology paints a very different picture. It shows that, while biodiversity loss is real and serious, the story of entire genera going extinct is slower, more localized, and less apocalyptic than many headlines suggest.

Led by John Wiens at the University of Arizona, the research looked beyond just charismatic animals like birds and mammals. By surveying all major groups of life, the team confirmed that 102 genera have disappeared since the year 1500. That number may sound large, but in context, it’s surprisingly low — and the pattern is not what many expected.

Extinction Risks Look Different by the Numbers

When most people hear the word “extinction,” they think of sweeping die-offs that erase whole branches of the tree of life. Yet Wiens and colleagues found that, across the past 500 years, extinctions have been rare. Less than 2% of bird and mammal genera have disappeared. For other groups, such as fish, insects, and plants, the rate is even lower, under half a percent.

Put another way: out of more than 22,000 genera examined, only 102 have gone extinct. That’s hardly the runaway collapse often portrayed. The broader lens of this study makes it clear that earlier alarm bells, which focused mostly on birds and mammals, missed the bigger, calmer picture.

Why So Many Losses Happen on Islands

Interestingly, the study shows that location seems to play a major role. Seventy-six percent of all genus extinctions took place on islands. Birds and mammals were hit hardest: 86% of bird genus extinctions and 76% of mammal genus extinctions were limited to island species.

Why islands? They are biodiversity hotspots, home to species found nowhere else. But they’re also fragile. When humans introduced predators like rats, cats, or pigs, island species had little defense. Hawaii, Madagascar, the Mascarenes, and New Zealand became ground zero for many of these losses.

The authors point out that while losing a genus on a single island is heartbreaking, it doesn’t have the same global consequences as extinctions spreading across continents. That distinction is critical in separating a regional tragedy from a planet-wide collapse.

When Extinctions Peaked and Then Slowed

If today feels like an ecological tipping point, the data suggest otherwise. By analyzing extinctions decade by decade, the researchers found that the worst periods were in the late 1800s and early 1900s. Since then, rates have actually declined.

Even after adding in genera considered “possibly extinct” — those that haven’t been seen for decades but aren’t officially gone — the trend was the same: the late 19th and early 20th centuries were the peak, followed by a long slowdown.

Why the drop? Conservation efforts deserve some credit. Programs to protect endangered species have helped prevent further losses, especially for birds and mammals. Another factor may be that the most vulnerable island species were wiped out early, leaving behind hardier survivors.

Beyond the Usual Suspects

Most warnings about mass extinction focus on tetrapods: mammals, birds, reptiles, and amphibians. But these creatures make up less than 2% of all known species. The new study widened the scope to include plants, arthropods, and fish, which represent the bulk of Earth’s biodiversity.

The results were striking. Only 0.08% of ray-finned fish genera are gone. Plants lost just 0.17%, arthropods 0.32%. And most of the 102 extinct genera consisted of only one species each, meaning their ecological footprint was relatively small.

Wiens and his team stress that this doesn’t mean all is well. Thousands of species still face threats from climate change, deforestation, and hunting. But the evidence suggests we’re not hurtling toward a mass extinction on par with the one that killed the dinosaurs.

What This Means for Conservation

Mass extinctions in Earth’s past wiped out 75% or more of all species in geologically short spans of time. Today’s losses, while concerning, don’t come close to that level when measured at the genus scale.

Instead of forecasting global collapse, the study highlights where we can make the biggest difference: islands. Protecting island ecosystems and controlling invasive species are practical, targeted steps that could prevent many future extinctions.

The authors also remind us that conservation isn’t just about safeguarding human interests. Every species carries inherent value. As they put it, preventing extinction is not only about what nature does for us, but also about recognizing the right of other living things to exist.