The notion of “planetary health”—that is, the close links between the health of ecosystems and that of human societies—is notoriously difficult to quantify. Difficult, but not impossible. This is the meaning of innovative work that the journal Science is highlighting its Friday, September 6 edition: environmental economist Eyal Franck (University of Chicago) shows that the collapse of American insectivorous bat populations was marked by a drop in agricultural production and offset by a considerable increase in the use of insecticides. Enough, in any case, for the consequences to be locally measurable on infant mortality.
The estimates are dramatic. Income and production losses for farmers total nearly $2.7 billion (€2.4 billion) per year between 2006 and 2017 in 245 of the counties included in the study. As for excess newborn mortality directly attributable to pesticide overuse, it is estimated at about 1,300 deaths in all the counties concerned during this same period.
To conduct his analysis, Mr. Franck took advantage of a formidable epizootic that appeared in 2006 in the northeastern United States, which affects bats. Caused by a pathogenic fungus, “white-nose syndrome” precipitates abrupt declines in these animals: as soon as the disease is detected in a territory, their populations can fall by more than 70% in a few months. After its appearance in 2006, explains the American economist, “The disease continued to spread in a staggered manner, so that each year more and more counties moved from being ‘unaffected’ to being ‘affected’ by the disease.”.
Fall in farm income
The researcher was thus able to compare data from affected areas with data from areas free of the pathogen. “An important result of the analysis is that both types of counties, affected and unaffected, see their results in terms of insecticide use and infant mortality evolve in a parallel manner in the years preceding the onset of the disease.explains Mr. Franck. But the data begin to diverge once bats start dying in counties where the disease takes hold. On average, affected counties saw insecticide use increase by 31 percent, with farmers compensating for the bats’ pest predation service. Locally, average farm income per square kilometer fell by 28.9 percent.
You have 62.41% of this article left to read. The rest is reserved for subscribers.
