Environmental degradation through mining for energy resources: The case of the shrinking Laguna Santa Rosa wetland in the Atacama Region of Chile

Abstract

As the world strives to replace fossil fuels with clean energy – reflected by global surge in the number of electric vehicles – the environmental impact of mining all the lithium (Li) needed to enable such a transformation has become a problem in its own right. In South America, the biggest problem is the excessive use of water in Li extraction process in one of the driest areas in the world. Apart from causing severe friction over water rights between local communities and mining companies, it puts enormous pressure on the region's fragile and poorly understood wetland ecosystems. Wetlands are one of the most threatened ecosystems on the Earth, despite their great importance as habitats for a vast number of species and corresponding to one of the most productive environments. Present work is the outcome of an investigation on Laguna Santa Rosa's (LSR) vulnerability resulting from ongoing metal mining operations in its surroundings that require a large volume of water extracted from local aquifers, in addition to a high evaporation rate in the area. This groundwater-dependent wetland will soon be further vulnerable with the commencement of water-intensive Li mining at Salar de Maricunga, with the extraction project already having an environmental impact study approved. Sustainability of this wetland protected under the Ramsar Convention and home to numerous wildlife species habiting this highland sector of the Andean Cordillera is vital for the associated ecosystems. The variation in the water surface area of LSR has been deciphered through the application of a Landsat-5 Thematic Mapper (TM) satellite image collection. This has been done both for the hydrological year 2016–2017 and 1993-2014 period. A decreasing trend in the water surface area of LSR, a hypersaline lake at the southern extreme of Salar de Maricunga, a salt flat in the Atacama Region of Chile, was observed through the study of satellite images between 1993 and 2014, showing shrinking of this wetland. However, this shrinking trend was punctuated by extreme rainfall and consequent flood with accumulated precipitation exceeding 40 mm in a single day and hourly mean rainfall rates higher than 10 mm/h recorded at several locations in the hyperarid Atacama Desert on March 25, 2015. This raised the lake's water level, and thus the areal extent of the lake water observed in the satellite images of the 2016–2017 hydrological year following the extreme weather events of 2015. The interplay of such extreme weather events and groundwater extraction for mining activities in the area complicates the assessment of the latter's effect on LSR, as the evaluation is constrained to the intervals between successive extreme weather events. In addition, the water level increases in summer because of the thawing of the snow. Close monitoring of the wetlands like LSR is essential to ensure their sustainability by considering both anthropic and climatic factors.