A new commentary in the journal Nature reveals that many species are threatened less by climate change than by overexploitation—human activities such as logging, fishing, and hunting. PHOTOGRAPH BY JONAS BENDIKSEN / MAGNUM

In January of this year, James Watson, an Australian scientist who works for the Wildlife Conservation Society, noticed an image that had been tweeted by a friend of his, a physician in Sydney. With a chain of progressively larger circles, it illustrated the relative frequency of causes of death among Australians, from the vanishingly rare (war, pregnancy and birth, murder) to the extremely common (respiratory disorders, cancer, heart disease). It was a simple but striking depiction of comparative risk. “I thought, ‘Why hasn’t anyone done something like this for the rest of nature?’ ” Watson recalled.

The answer was that, until recently, nobody had the data. While many scientists have studied the vulnerability of individual species or groups of organisms (corals, say, or birds) to extinction, only in 2010 did ecologists, conservationists, taxonomists, and naturalists begin to more comprehensively assess the threats posed to species of all kinds—an effort to assemble what the biologist E. O. Wilson has called a “barometer of life.”

Over four months this spring, Watson and Sean Maxwell, a doctoral student at the University of Queensland, used the new data to identify and rank the existential threats to nearly nine thousand species, ranging from otters to lilies. In a commentary published today in the journal Nature, they report that almost three-quarters of the species they studied are threatened by overexploitation—human activities such as logging, fishing, and hunting. More than sixty per cent are threatened by the conversion of habitat to farmland and timber plantations. (Many species face multiple threats.) Less than twenty per cent, however, are currently endangered by the many effects of climate change—drought, extreme temperatures, severe storms, and flooding.

Like other conservationists, Watson and Maxwell were already well aware that poaching and agriculture posed serious threats to many species. But even they were surprised by how dramatically the effects outstripped those of climate change. Much like the causes of human death, the current causes of species loss appear to be inversely proportional to the media attention—and, to some extent, the research and funding attention—they receive.

Much has been written about the challenges of covering climate change as news: its effects are often uncertain, gradual, and distant, and its causes are multiple (i.e., you, me, and everyone else). Unlike the proverbial house fire, whose effects are immediate and easy to photograph, climate change is narratively impaired. But, compared with other threats to biodiversity, it has the advantage of relative novelty and, in recent years, of urgency, as international negotiators race to keep the rise in average global temperatures below the measurable, if somewhat arbitrarily identified, threshold of two degrees Celsius. Habitat loss and overhunting, on the other hand, are stories almost as old as humanity. They rarely make news—until it’s too late for the species involved.

The magnitude of these ancient threats is, of course, no excuse for climate complacency. While the harms that climate change does to biodiversity—and humanity—lie mostly in the future, and their specifics remain uncertain, their significance is beyond doubt. Still, the Nature analysis serves as an important reminder. “It doesn’t in any way change the importance of addressing climate change, but I think it tells us that we absolutely have to tackle these more immediate threats,” Thomas Brooks, the head of science and knowledge at the International Union for Conservation of Nature and a co-author of the commentary, told me. “If we don’t address them, we’re going to lose most of our biodiversity, no matter what we do about climate change.”

Fortunately, some of the very qualities that make for lousy headlines—familiarity and incremental change—denote uncomplicated solutions. “We know what kind of mechanisms we need to put in place, and we know how and where to establish protected areas,” Brooks said. “We don’t need massively new science. We know what to do.” He hopes to see new attention paid to these familiar threats next month at the World Conservation Congress, the quadrennial global meeting of the more than two hundred states and government agencies and more than a thousand conservation groups that make up the I.U.C.N.

Knowing what to do and being able to do it are two different things, and the political obstacles to agricultural reform and poaching protections—local, national, and global—are often enormous. But Jonathan Foley, the executive director of the California Academy of Sciences and an expert on the effects of agriculture on biodiversity, pointed out that both humans and other species stand to gain a great deal from relatively painless reforms: stopping the habitat destruction and exploitation involved in the production of luxury goods and crops, reducing food and water waste, and reining in fertilizer use on the relatively small number of farms that generate most of the world’s nitrogen and phosphorus pollution. “The good thing about really stupid things is that you can stop doing them,” Foley said.