19 May 2023

500,000 deaths a year linked to the decline in pollinators

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The decline in pollinating insects has negative effects on the availability and price of healthy foods such as nuts, legumes, fruit and vegetables, causing an increase in premature deaths. PHOTO: Pixabay

The “prudential” estimate is contained in a new international study published in Environmental Health Perspectives. Premature deaths are thought to be caused by decreasing availability and rising prices of healthful foods, which are in turn linked to the global decline of bee and pollinators

by Emanuele Isonio

 

It’s a perfect example of the butterfly effect. And never has a metaphor been more suitable. Indeed, a vicious circle starts from the decline of butterflies, bees and many other pollinating insects which ends with the death of hundreds of thousands of people around the world every year. At least half a million premature deaths. The estimate, which is considered conservative, is contained in a new international study published in the journal Environmental Health Perspectives. Among the authors, professors and researchers from Oxford, Harvard and Columbia University.

To understand better: those data are analogous to the number of deaths caused each year by drug use or by prostate cancer.

But what link unites the collapse in the number of pollinators with our health? Obviously, the food. In particular fruit, vegetables and all those essential foods for a healthy diet. Fewer pollinators means less availability of these products (and therefore an increase in their price). Which makes them gradually disappear from tables around the world.

Figure 1. Schematic depicting the chain of modules that constituted our overall model. Arrows show where outputs of one module serve as inputs to another. Module C received inputs from both modules A and B, which connected to module D, then to module E. SOURCE: Pollinator Deficits, Food Consumption, and Consequences for Human Health: A Modeling Study

Schematic depicting the chain of modules that constituted our overall model. Arrows show where outputs of one module serve as inputs to another. Module C received inputs from both modules A and B, which connected to module D, then to module E. Note: mod, module.

The pollinator-food-human health link

For their calculation, the researchers referred to a work published in 2016 in Science. This study had the merit of estimating how much of the gap in agricultural production between medium-sized farms and those that ensure the majority of crops was linked to insufficient pollination. For this, they had monitored 344 agricultural fields, dependent on 33 pollinating insects around the world. That study found that about 25% of the yield gap was likely related to the loss of the most important of the ecosystem services provided by pollinators.

From that baseline, the working group calculated that the decline in insect numbers caused a 4.7 percent decrease in fruit and nut production and a 3.2 percent decrease in vegetable production. At that point they went on to analyze the link between healthy living and the daily availability of these foods on our tables.

“We estimated how eating more of these healthy foods would benefit your health,” says Matthew Smith, a researcher in Harvard’s Department of Environmental Health and lead author of the research. “To do this, we drew on robust epidemiological research that has linked increased consumption of fruits, vegetables and nuts to reduced mortality from many major chronic diseases such as heart disease, stroke, cancer and diabetes.”

Most affected? Middle-income countries

The research then goes more specifically to investigate in which areas of the world the link between premature deaths and pollinator decline is strongest. According to their analyses, the most affected nations are middle-income countries. Russia, China and India, in particular. Areas where there is already a high propensity to die from cancer, diabetes and stroke. The impact on rich countries is instead less strong because their population is on average more able to support the increase in fruit and vegetable prices.

 Current annual mortality estimated to be attributable to inadequate pollination and its dietary effects, by cause of death and country income. Inadequate pollination is defined as a combination of too-little flower visitation and scant pollinator diversity to achieve optimal yields. SOURCE: Pollinator Deficits, Food Consumption, and Consequences for Human Health: A Modeling Study, 2022.

Current annual mortality estimated to be attributable to inadequate pollination and its dietary effects, by cause of death and country income. Inadequate pollination is defined as a combination of too-little flower visitation and scant pollinator diversity to achieve optimal yields. More information of “other risk factors” and causes of negative values may be found in the caption for Table 2. Source data may be found in Excel Table S6.

Paradoxically, however, the least affected areas are those in which food insecurity is already greater, such as sub-Saharan Africa and Latin America. But the paradox is only apparent: “Many of those countries have low incomes – explains Smith – and therefore healthy products are already inaccessible for them today. Moreover, they are areas in which chronic diseases are much less widespread than in the richest countries”.

However, this does not mean that even among the poorest territories the decline of pollinators is not a problem. In countries such as Indonesia, Vietnam and Myanmar, fruit consumption has decreased by 7-15% due to the decline of bees and other insects, an average rate higher than that recorded in other states. And the same countries suffer from significantly higher stroke rates than the global average.

Concerns and solutions for the future

Moreover, the increase in the human population worldwide, which has already exceeded 8 billion individuals and is estimated at 9.7 billion within the middle of the century, can only worsen the estimates. In fact, the demand for food resulting from pollination will increase (no less than 75% of food raw materials depend on insects). “To meet their needs we will need significant increases in pollinated food production,” Smith recalls. “So either we significantly increase the number of wild pollinators or we will be forced to strengthen intensive conventional agriculture, which however damages our global environment, with enormous quantities of greenhouse gases, soil pollution, contamination and depletion of water basins, depletion of resources needed for fertilizers, loss of biodiversity”.

Hence the call to protect habitats for pollinating insects and create solutions to stimulate their growth. Remedies that can be developed at many different levels: from the individual farmer up to the national government or supranational level. For example by reserving small areas on each farm for their foraging. At the same time, according to Smith, it is necessary to continue with the “progressive elimination of the use of pesticides harmful to the life of bees and other beneficial insects, starting with neonicotinoids”.