A groundbreaking study published in Science has revealed a shocking link between the decline of bat colonies across the United States and the deaths of over 1,300 children. Environmental economist Charles Taylor from Harvard Kennedy School notes that this finding is rare, as it demonstrates a causative link between human and bat wellbeing.
The crisis began in 2006 when a fungus called Pseudogymnoascus destructans spread to US bat colonies, killing them off in as little as five years. Assistant professor Eyal Frank of the University of Chicago took advantage of this natural experiment to study the value of bats. His research found that farmers significantly increased their use of insecticides by 31.1% on average after the bat decline.
Frank then examined infant mortality rates, finding a 7.9% increase in death rates for infected counties compared to those with healthy bat populations. This translates to an estimated 1,334 extra infant deaths. After controlling for other factors that could explain the rise in deaths, Frank found that the results held, providing compelling evidence that farmers responded to the decline in insect-eating bats and that this response had a negative health impact on human infants.
Taylor emphasizes that it is unusual for a study of this type to suggest causation rather than correlation. The study’s findings echo previous research, including Taylor’s own study on cicadas, which showed increased pesticide use during their emergence periods, resulting in higher infant mortality rates.
The study joins a body of evidence dating back to the 1960s that pesticides have adverse effects on human health. As noted by Columbia history professor David Rosner, it is shocking that this continues to be discovered year after year despite the accumulation of evidence.
Source: https://www.theguardian.com/environment/article/2024/sep/05/loss-of-bats-to-lethal-fungus-linked-to-1300-child-deaths-in-us-study-says-aoe