Amazon fires are causing glaciers in the Andes to melt even faster ObserverMatthew Harris Climate Science, Keele UniversityNovember 28, 2019 Fires occur in the rainforest every year, but the past 11 months saw the number of fires increase by more than 70% when compared with 2018, indicating a major acceleration in land clearing by the country’s logging and farming industries. When fires in the Amazon emit black carbon during the peak burning season (August to October), winds carry these clouds of smoke to Andean glaciers, which can sit higher than 5,000 metres above sea level. Despite being invisible to the naked eye, black carbon particles affect the ability of the snow to reflect incoming sunlight, a phenomenon known as “albedo”. Similar to how a dark-coloured car will heat up more quickly in direct sunlight when compared with a light-coloured one, glaciers covered by black carbon particles will absorb more heat, and thus melt faster. By using a computer simulation of how particles move through the atmosphere, known as HYSPLIT, the team was able to show that smoke plumes from the Amazon are carried by winds to the Andes, where they fall as an invisible mist across glaciers. Altogether, they found that fires in the Amazon in 2010 caused a 4.5% increase in water runoff from Zongo Glacier in Bolivia. The smoke from the fires rose high into the atmosphere and could be seen from space. Some regions of Brazil became covered in thick smoke that closed airports and darkened city skies. As the rainforest burns, it releases enormous amounts of carbon dioxide, carbon monoxide, and larger particles of so-called “black carbon” (smoke and soot).
The phrase “enormous amounts” hardly does the numbers justice – in any given year, the burning of forests and grasslands in South America emits a whopping 800,000 tonnes of black carbon into the atmosphere. This truly astounding amount is almost double the black carbon produced by all combined energy use in Europe over 12 months. Not only does this absurd amount of smoke cause health issues and contribute to global warming but, as a growing number of scientific studies are showing, it also more directly contributes to the melting of glaciers. In a new paper published in the journal Scientific Reports, a team of researchers has outlined how smoke from fires in the Amazon in 2010 made glaciers in the Andes melt more quickly. Crucially, the authors also found that the effect of black carbon depends on the amount of dust covering a glacier – if the amount of dust is higher, then the glacier will already be absorbing most of the heat that might have been absorbed by the black carbon. Land clearing is one of the reasons that dust levels over South America doubled during the 20th century. Glaciers are some of the most important natural resources on the planet. Himalayan glaciers provide drinking water for 240m people, and 1.9 billion rely on them for food
In South America, glaciers are crucial for water supply – in some towns, including Huaraz in Peru, more than 85% of drinking water comes from glaciers during times of drought. However, these truly vital sources of water are increasingly under threat as the planet feels the effects of global warming. Glaciers in the Andes have been receding rapidly for the last 50 years. The tropical belt of South America is predicted to becomemore dry and aridas the climate changes. A drier climate means more dust, and more fires. It also means more droughts, which make towns more reliant on glaciers for water. Unfortunately, as the above study shows, the fires assisted by dry conditions help to make these vital sources of water vanish more quickly.....read on https://theconversation.com/amazon-fires-are-causing-glaciers-in-the-andes-to-melt-even-faster-128023
