Researchers have found that burning of the rainforest in southwestern Amazonia (the Brazilian, Peruvian and Bolivian Amazon) may increase the melting of tropical glaciers in the Andes, South America. For the study, published in the journal Scientific Reports, researcher Newton de Magalhães Neto and colleagues from Rio de Janeiro State University, Brazil, modelled the possible effect of biomass burning in the Amazon Basin on the Bolivian Zongo Glacier using data collected between 2000 and 2016 on fire events, the movement of smoke plumes, precipitation and glacier melting.
They found that aerosols from biomass burning, such as black carbon, can be transported by wind to tropical Andean glaciers. There they are deposited in snow and have the potential to increase glacier melting as snow that is darkened by black carbon or dust particles reflects less light (reduced albedo).
Focusing their analyses on the years 2007 and 2010 when fire seasons were the most critical for the Amazon Basin, the authors investigated the snow albedo reduction due to black carbon alone and black carbon in the presence of previously reported quantities of dust. Their model showed that black carbon or dust alone had the potential to increase annual glacier melting by three to four per cent; or by six per cent when both were present.
If dust concentrations were high, dust alone had the potential to increase annual melting by 11-13 per cent and by 12-14 per cent in the presence of black carbon. The findings suggest that the impact of Amazon biomass burning depends on the dust content in snow.
Concerns over fires in the world's largest tropical forest.
Pressure related to global food demand may result in further expansion of Brazilian agriculture and deforestation, resulting in enhanced black carbon and CO2 emissions that may impact Andean glaciers. In September 2019, seven South American countries have agreed measures to protect the Amazon river basin, amid concerns over fires in the world's largest tropical forest.
Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru and Suriname signed a pact, setting up a disaster response network and satellite monitoring. The Amazon is a vital carbon store that slows down the pace of global warming, and 60 per cent of it is located in Brazil. The number of fires between January and August 2019 is double that of the same period last year, according to the country's National Institute for Space Research (Inpe).
Several international retailers have said they are suspending purchases of Brazilian leather because of the links between cattle ranching and the fires devastating parts of the Amazon rainforest. Earlier in August, Brazilian President Jair Bolsonaro has rejected a $22 million aid package offered by G7 countries to help battle fierce forest fires in the Amazon rainforest.
