The melting of Andean glaciers has increased recently with consequent effects on the future availability of water for humans, agriculture and indeed mining. It also contributes to the world-wide loss of glaciers. Between 2006 and 2015, 278 billion tonnes of ice were lost every year from Greenland, 155 billion tonnes per year from Antarctica, and from glaciers another 220 billion tonnes per year. For fuller details see “The Ocean and Cryosphere in a Changing Climate” from IPCC 2019.
A study published two weeks ago in Nature provides important and provoking findings about the effect of fires in the Amazon. The work is from Brazilian and French scientists.
Using data from ice cores, meteorological conditions etc, they explore the relationship between black carbon from biomass burning in the Amazon and from dust aerosol, and the rate of melt of an Andean glacier. The detailed measurements and modelling use the Bolivian Zongo glacier for which good data is available. They show that the black carbon carried by the wind is deposited on the glaciers. The darkening causes a reduction in the glacier’s ability to reflect sunlight (albedo), hence speeding up the rate of melt, a result already known in polar glaciers from carbon emitted by Europe.
The scientists note that the effect will occur in other parts of the Andes. The details of the effects will be different depending on the location, prevailing winds etc., but the models produced from this study on one glacier should be more generally applicable for predictive purposes, though further work in other situations is needed to confirm this.
The study is a further reminder that forest fires do not have to be in the Peruvian Amazon to have serious effects for the country as a whole.