Over the past decade, Brazil has made some effort to reduce deforestation in the Amazon rainforest. This was also the country’s primary contribution to the fight against global warming. However, despite a 76 percent decline in deforestation rates over the last 13 years, those efforts might now be offset by drought-induced fires, according to a study recently published in Nature Communications.
According to a group of researchers connected to Brazil’s National Institute for Space Research (Inpe), the 2015 drought alone led drought-induced fires to increase by 36 percent when compared to averages for the previous 12 years. These fires could generate emissions of up to one billion tons of carbon dioxide (CO2), which contributes to the greenhouse effect as well as the increase in global temperatures.
To reach such conclusions, Inpe researchers analyzed satellite data to measure variables including rainfall, fire incidence, and temperature variations on the ocean surface (that last variable is important because it influences how much humidity is released from the ocean onto the continent, thus influencing rainfall in the forest).
The Amazon rainforest experienced three major drought years over the past decade and a half, in 2005, 2010, and 2015. The last drought was the worst of the three, affecting roughly 2 million square kilometers, or 43 percent of the Brazilian Amazon. The affected area was not limited to regions close to agricultural properties, where deforestation is more intense.
In a way, the study confirms many of the more pessimistic forecasts about global warming. Programs to predict climate trends had already indicated that droughts would be more intense in the Amazon region over the 21st century. In the coming decades, according to the study, “degraded forests may become increasingly dry and susceptible to forest fires.”
As droughts become more frequent, they can create a vicious cycle of environmental degradation. With less rainfall in the region, trees are more likely to die or prematurely lose their leaves. The consequence is that more organic and inflammable matter would be accumulated in the soil, thus leading to more fires.
Another problem relates to the current state of the Amazon rainforest. Numerous areas in the region are fragmented – that is, there are isolated areas of the forest disconnected from the rest of the ecosystem. These isolated areas are especially vulnerable to fires because local rural producers use slash-and-burn methods, where fires are used to create a field for their crops.
With droughts becoming more frequent, they have been responsible for a large portion of fires in the Amazon region. Until 2004, when Brazil’s federal plan to control deforestation was implemented, 84 percent of all fires in the region were human-induced. Between 2004 and 2015, however, that rate dropped to 47 percent, meaning that climate changes have become the main factor in Amazon fires.
That change will force Brazil to fight CO2 emissions with more creativity than simply curbing timber extractors and farmers. The country, responsible for 2.5 percent of the world’s carbon dioxide emissions, has pledged to a 37 percent cut in emissions by 2025, and an “intended reduction” of 43 percent by 2030.