Pollinators like bees, butterflies, bats and moths help farmers grow healthy foods. They support the production of vegetables, fruits, nuts and legumes—but now, when there are fewer pollinators around to help plants reproduce, crop yields are decreasing.
A new study finds the world is losing 3 to 5 percent of its fruit, vegetable and nut production because of shrinking pollinator populations and lower pollinator diversity. Those losses, in turn, mean that people have less healthy food to eat and suffer from associated health conditions like diabetes and heart disease.
Based on modeling, these health effects lead to an estimated 427,000 excess deaths per year—on the same order of magnitude as prostate cancer, interpersonal violence and substance use disorders, according to the researchers.
The team published a new paper about these findings last week in the journal Environmental Health Perspectives.
Scientists know that pollinators are suffering because of human activities, including the use of harmful pesticides, climate change, air pollution, farming practices and land-use changes. They also know that 80 percent of all flowering plants—including food crops—rely on pollinators to reproduce. But, until recently, no one understood how pollinator losses have affected humans’ well-being.
“A critical missing piece in the biodiversity discussion has been a lack of direct linkages to human health,” says senior author Samuel Myers, a planetary health scientist at Harvard University, in a statement.
Using data from hundreds of experimental farms across Africa, Asia, Europe and Latin America, the researchers looked to quantify this “pollinator yield gap.” They estimated dietary risk factors, mortality and economic loss based on this crop and pollinator data, as well as information on diet, chronic diseases and international trade.
They find that “insufficient populations of pollinators were responsible for large present-day burdens of disease through lost healthy food consumption,” the team writes in the paper.
“This research underlines just how critical pollination services are to human health and well-being,” Kelly Bills, executive director of the non-profit Pollinator Partnership, who was not involved in the study, tells New Scientist’s Gary Hartley.
The health impacts are accompanied by an economic toll, and these dual consequences affect various parts of the world differently. Lower-income countries bear the brunt of lost food production and, as a result, are losing revenue, whereas middle- and higher-income countries are suffering more of the health consequences, the researchers find.
In three countries—Honduras, Nepal and Nigeria—the scientists estimate that pollination deficits are responsible for a reduction of 3 to 19 percent in crop yields, which translates to economic losses of 12 to 31 percent.
The researchers note that their findings are likely conservative, because they only studied deaths from diseases linked to diet. However, pollinator decline is likely harming human health in other ways, too, such as through less access to pollinated medicinal plants and bee products, or deficiencies of micronutrients like vitamin A and folate. And because of lost crop production and revenue, farmers in lower-income countries don’t have as much money to spend on their own health.
Pollinator populations could decline even more unless humans make changes, such as limiting pesticide use, maintaining existing natural habitats and restoring others, and planting more flowers and diverse plants. Unless we take action to make the world better for pollinators, this study shows we will suffer the health consequences.
“It’s well accepted that pollinators are an important part of Earth’s precious biodiversity, and most people have really taken to heart that they play a key role in supporting food supplies and diets,” says study co-author Matthew Smith, an environmental health scientist at Harvard, to New Scientist. “Adding the extra dimension of human health introduces an even more urgent imperative to policy-makers: Protecting and growing a robust pollinator population not only helps protect key foods, but also supports public health.”