Quantifying rates of glacier recession in the Peruvian Andes since the Little Ice Age

Peru hosts 92% of the total glacierised area of the tropics, and those glaciers are losing mass at an unprecedented rate with ongoing climate change. This glacier mass loss delivers meltwater that has the potential to have dramatic and dangerous impacts on the local – and larger-scale – surroundings via meltwater release. This study uses extensive geomorphological evidence detected within high resolution digital elevation models and satellite imagery, together with GIS reconstructions, to determine glacier area and volumetric changes since the Little Ice Age (LIA) maximum (1579 to 1728). These data show a reduction in glacierised area of 45% and a reduction in volume of 40% (almost 75 km3) when aggregated across all Peruvian Cordilleras. Using the median date for the LIA maximum, this volume loss equates to 6.34 x 10-5 km3 yr-1 km-2, with a mass balance of -0.3 ± 0.09 m w.e. yr-1 and sea level equivalent of 0.17 mm, or 0.0005 mm yr-1, between 1644 and 2003. When six of Peru’s Cordilleras are compared, no significant difference between rates of recession is observed, which indicates that the response of these glaciers to long-term climate change is driven by large-scale climatic controls. Overall, this study contributes to the improved understanding of spatial and temporal rates of glacier melt in Peru by providing novel long-term data over a broad area, and provides a literature analysis to contextualise the rapid rates of contemporary glacier recession within a long-term record.