Amazon forest fires melting glaciers over 2,000 km away: Study

Fires in the Amazon rainforest are melting glaciers more than 2,000 kilometres away in the Andes mountain range in South America, according to a study.

The study, published in the journal Scientific Reports, 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), the researchers said. Newton de Magalhaes Neto from Rio de Janeiro State University in Brazil, and his colleagues modelled the possible effect of biomass burning in the Amazon Basin on the Bolivian Zongo Glacier.

They used data collected between 2000 and 2016 on fire events, the movement of smoke plumes, precipitation, and glacier melting. The researchers focussed their analyses on the years 2007 and 2010, when fire seasons were the most critical for the Amazon Basin. They 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 3-4 per cent, or by 6 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, according to the researchers. The findings suggest that the impact of Amazon biomass burning depends on the dust content in snow, they said. Pressure related to global food demand may result in further expansion of Brazilian agriculture and deforestation, resulting in enhanced black carbon and carbon dioxide emissions that may impact Andean glaciers, the researchers said.