Decreasing rural populations lead to increasing fires in Amazonia

Fires in the Amazon leave clouds of smoke over northern Brazil.

NASA

Fire has been used as an agricultural management tool for millennia. It helps to combat pests, weeds and disease, clears debris, and recycles nutrients in the soil. But over the last decade, destructive fires have been taking their toll on the Amazon. These fires lead to forest degradation, release stored carbon into the atmosphere, impair air quality, and damage property.

While previous studies have found that drought and proximity to roads increase the frequency of fires, a team of researchers from Columbia University and the Center for International Forestry Research have found a new cause. Their study, published in the Proceedings of the National Academy of Sciences, found that decreases in rural populations is an additional factor in the increased incidence of fires.

Factors that contribute to fires are poorly understood, and climate variability has only made the picture murkier. Climate is changing patterns of drought and humidity. Severe droughts hit Amazonia in 2005 and 2010, and agriculture-related fires became a major problem in their aftermath. In addition to drought, increased fire risk in the Peruvian Amazon is likely due to a several factors that interact with drought severity, such as increased flammability of forests due to timber extraction, and the repeated burning for extension of roadways.