Humans Are Doing a Remarkable Job of Killing the Species That Feed Us

From almonds to apples, our food supply relies in large part on the industriousness of buzzing pollinators.

But human activities could wipe out many birds, bees, bats, and butterflies, along with hundreds of billions of dollars of food they help grow each year, according to a new United Nations report.

In the first ever global assessment of the issue, a UN science group found that pollinators around the world are in dramatic decline — but also that it is not too late to change the practices that are a threat to them.

Each year, pollinators — especially the over 20,000 species of bees — contribute to producing up to $577 billion worth of fruits, vegetables, and other food, according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). The report found that 75 percent of the world's crops depend, at least in part, on pollinators, and it warned that 16 percent of vertebrate pollinators, like hummingbirds and bats, are threatened with extinction, while, in some regions, as many as 40 percent of pollinating insects could face the same fate.

"When you mention bees, a lot of people think of stings, not of honey or of crop pollination," said Peter Kevan, an agricultural scientist at the University of Guelph and a lead author on the IPBES report. "There's an awful lot of food on their table that they rely on that comes about through the [pollination] system being functional."

More than 80 scientists from around the world reviewed some 3,000 studies in order to come to their results. The report was produced over two years and, while there remains inadequate data in some areas, myriad regional studies from North America and Europe, point to a host of threats. These include invasive species and disease, but also man-made risks from agricultural practices, climate change, and the heavy use of pesticides.

Widespread worry about pesticides dates back at least to Rachel Carson's 1962 book Silent Spring, which led the US government to ban DDT from use in agriculture. The report, however, stressed that it is not simply the use of pesticides that is the problem. Indeed, Kevan pointed to them as an important tool for food production, but said that it is the overuse of pesticides — especially the controversial neonicotinoid class — that threatens bees and other pollinators.

The report states that the question of whether or not the use of neonicotinoid at any level is harmful to insects "is currently unresolved." But Vera Lucia Imperatriz-Fonseca, a co-chair of the assessment and professor at the University of São Paulo, said, "we have more than enough evidence to act" on moderating the use of pesticides.

Related: Rising Temperatures Are Squishing Bumblebee Habitats

The effect of pesticides is also complexly intertwined with the impact of intensive single-crop farming, which reduces plant diversity that sustains pollinating insects, and the warming climate, which alters the environment and behavior of pollinators. The IPBES report calls for more research into the intersection of these factors, but also notes many options for immediate action, including more diversified agriculture and reducing and localizing the use of pesticides.

Policy makers are beginning to pay attention to the plight of pollinators, and what it means for the food supply. Last year, the Obama administration announced an initiative to protect honeybees and scrutinize the effects of pesticides. State governments have also taken action and the IPBES report was endorsed by more than 100 member countries.

According to biologist Jeremy Kerr, who authored a landmark study on how rising temperatures endanger honey bees, the resilience of pollinating insects means that relieving the pressure from just one or two of the many threats may give them space to adapt to the others. Protecting pollinators, the University of Ottawa professor said, requires policy changes but can also be as simple as planting flowers on roadsides or buying local produce. The key, he stressed, is to act fast.

"The problem of pollinator decline is real and it is right now," said Kerr, likening pollinators' unnoticed importance for human life to that of oxygen. "They support things that we cannot do without."

Related: This Pesticide Might Be Killing off Bees

Follow Jake Bleiberg on Twitter: @jzbleiberg