The Andean Glacier and Water Atlas

on the Nevado de Tolima will likely disappear before 2030, and most of the glaciers in the Sierra Nevada de Santa Marta and Sierra Nevada de El Cocuy will be gone before 2050. They suggest that only a few of the largest glaciers on the highest parts of the Nevado del Huila, Nevado del Ruiz and in the Sierra Nevada de Santa Marta and Sierra Nevada de El Cocuy will exist beyond the middle of this century, and those that do survive will be much reduced. Schauwecker et al. (2017) modelled the change in freezing level height to estimate the future extent of glaciers in Peru. The mass balance of tropical glaciers is sensitive to the rise in freezing level height due to a decrease in accumulation. They found that by the end of the 21st century, the freezing level height will rise by 230 m (±190 m) for the low IPCC (2014) global warming scenario and 850 m (±390 m) for high scenario. They conclude that even with the best scenario glaciers will continue to shrink and with the highest warming scenario glaciers may only remain at the highest summits (above 5,800 m asl). In the Southern Andes a future temperature increase is predicted, with values ranging from about 1°C for the more moderate IPCC scenario, up to 7°C for the extreme scenario (IPCC, 2014). As a direct consequence of warmer atmospheric temperatures, the freezing level height and the Equilibrium Line Altitudes (ELAs) in the Southern Andes are predicted to continue to rise, with an associated loss of glacier mass at an increasing rate (Carrasco et al., 2005, 2008; Fig. 8). Small glaciers such as Echaurren Norte are predicted to disappear by 2040-2045 (CECs, 2009).

Glaciological models run under different emission scenarios by the Intergovernmental Panel on Climate Change (IPCC) suggest that in the future, tropical glaciers will decrease most dramatically in volume. The predicted decrease is dependent on which scenario is used to calculate volume loss. For example, for the moderate IPCC climate warming scenario (2014) volume losses of 78–97 per cent are predicted, while for a high emission scenario losses increase to 93-100 per cent (Radić et al., 2014). Rabatel et al., (2018) have estimated the future changes in Colombian glaciers. Extrapolating from the observed glacier surface area shrinkage rates over the last decades, indicates that glaciers

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