In 2017, an evolutionary biologist named R. Alexander Pyron ignited controversy with a Washington Post commentary titled “We don’t need to save endangered species. Extinction is part of evolution.” He wrote: “Conserving a species we have helped to kill off, but on which we are not directly dependent, serves to discharge our own guilt, but little else.”

Pyron’s take challenged the decades-old idea that biodiversity is a good thing — that humans should strive to preserve all forms of life on Earth and their interconnectedness across ecosystems. It prompted scientist and writer Carl Safina to mount a passionate defense of biodiversity, calling Pyron’s stance “conceptually confused” and containing “jarring assertions.” Safina’s most cutting rebuke was that belittling biodiversity derails environmental conversations. “It’s like answering ‘Black lives matter’ with ‘All lives matter,’” he wrote. “It’s a way of intentionally missing the point.”

Nobel Prize winners co-signed more rebuttals. Professors blogged long meditations on why endangered species need to be saved. There were scientists who had previously questioned a hyperfocus on saving species, to be sure, though none had done so in such a public and broad-sweeping manner as Pyron. Josh Schimel, an ecologist at UC Santa Barbara, wrote: “Remember, you are a scientist — it is not your job to be right. It is your job to be thoughtful, careful, and analytical.” Pyron declined a request for comment for this story.

Ginger Allington, a landscape ecologist and professor at George Washington University who tracks the scientific debate around “biodiversity,” says this scientific back-and-forth reflects increasing conflict about the importance of biodiversity and species loss.

The most common way to measure biodiversity is to count the number of species in a certain place, also known as “species richness.” But critics question the usefulness of this number and argue that the concept has always been fuzzy, even to scientists, akin to a “new linguistic bottle for the wine of old ideas.”

A handful of scientists want to do away with the term biodiversity altogether — and have been trying to do so since the late 1990s. The concept, they say, is hard to quantify, hard to track globally over time, and actually isn’t an indication of what people commonly picture as a “healthy” ecosystem. (Scientists are generally reluctant to describe ecosystems in terms of “healthy” or “unhealthy,” which are value judgments.)

Last year, the United Nations reported that the world has failed to reach even one of the major biodiversity conservation targets it had set for itself in 2010. In the face of accelerating species and habitat loss, countries are now committing to protecting 30 percent of land and water by 2030. This fall, 193 nations are set to attend the virtual Convention on Biological Diversity to hash out a plan to stop biodiversity loss. (A draft of that plan was published last month.) In the US, the Biden administration has proposed its own game-changing approach to nature conservation. Meanwhile, a coronavirus pandemic that may have begun in animals reminds us that we are fundamentally linked to the animals in these critical habitats.

Against this backdrop, a new generation of scientists is taking up the debate about what to do about “biodiversity” itself — the scientific concept, its popular understanding, and indeed the very word. As Allington told Vox: “There’s just a lot of drama.”

The backstory of biodiversity

Before there was biodiversity, there was BioDiversity. A key moment in the evolution of the word came at the National Forum on BioDiversity, held at the Smithsonian Institution and National Academy of Sciences, in 1986. Speakers included Jared Diamond, who later authored Guns, Germs, and Steel, and the biologist E.O. Wilson, who most recently popularized the idea of protecting half the planet.

Diamond and Wilson — along with seven other white male scientists in attendance — dubbed themselves the “Club of Earth” and held a press conference, telling reporters that biodiversity loss was the second-biggest “threat to civilization.” The first? Thermonuclear war.

Few women scientists or non-Western experts were featured. And not everyone felt comfortable crowning biodiversity as a scientific silver bullet, for that matter. One news report from the time quoted biologist Dan Janzen, who said at the forum that “one shouldn’t use the number of species as the only criterion for earmarking an area for conservation.” Janzen would later call the forum “an explicit political event” and said that the word biodiversity got “punched into that system at that point [in time] deliberately.”