During the late 1980s and early 1990s, industrial pollution and its effects on the natural environment became a matter of widespread concern in America and elsewhere. Today, not much has changed, as climate change caused by greenhouse gas emissions is largely considered to be the most pressing environmental issue facing the world. However, 30 years ago, the threat of acid rain dominated headlines. Much of the scientific community at the time considered acid rain to be a potentially disastrous consequence of industrial air pollution. Acid rain forms when sulfur dioxide (SO2) and nitrogen oxides mix with water and oxygen in the atmosphere. This mixture results in the formation of corrosive sulfuric and nitric acid droplets that literally rain down from the sky. These harmful gases are released as byproducts of industrial processes. The smoke emitted from smokestacks is the most significant source of these gases in urban areas, but the formic acid produced naturally by ants is considered to be the primary component of acid rain in less industrialized areas, most notably in the Amazon. Although acid rain is not a commonly discussed consequence of industrial pollution today, researchers remain convinced that ants serve as primary contributors to acid rain-formation in rural regions.

The ants that emit formic acid as a defensive chemical during violent encounters are known as formicine ants, and they are numerous within tropical regions. A New York Times article from 1987 described how formicine ants are responsible for occurances of acid rain in remote areas of the world. Researchers from Cornell calculated that formicine ants dwelling within the Amazon release as much as 200 million tons of formic acid into the atmosphere each year, which is sufficient for the formation of acid rain. While the association between ants and acid rain formation has not been discussed widely in the media for the past few decades, a 2010 study confirmed that formicine ants are responsible for a majority of the formic acid emissions that reach the troposphere in large and remote locations where industrial pollutants are largely absent.

Do you believe that acid rain is should not be considered a pressing environmental issue since it likely forms naturally as a result of formicine ant activity in remote regions?