Vanishing of very small glacierets throughout the Northern and Central Andes of Chile
Resumen
Small glaciers ( less than 0.5 km 2 ${ \lt }0.5\,\mathrm{km}^2$ <mml:math xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest" xmlns:cup="http://contentservices.cambridge.org" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://cambridge.org/core/metadata" xmlns:core="http://cambridge.org/core" xmlns:c="http://cambridge.org/core/content" display="inline"> <mml:mrow> <mml:mrow> <mml:mo><</mml:mo> </mml:mrow> <mml:mn>0.5</mml:mn> <mml:mspace width="0.167em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">k</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> ), glacierets ( less than 0.25 km 2 ${ \lt }0.25\,\mathrm{km}^2$ <mml:math xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest" xmlns:cup="http://contentservices.cambridge.org" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://cambridge.org/core/metadata" xmlns:core="http://cambridge.org/core" xmlns:c="http://cambridge.org/core/content" display="inline"> <mml:mrow> <mml:mrow> <mml:mo><</mml:mo> </mml:mrow> <mml:mn>0.25</mml:mn> <mml:mspace width="0.167em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">k</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> ) and, in particular, very small glacierets ( less than 0.01 km 2 ${ \lt }0.01\,\mathrm{km}^2$ <mml:math xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest" xmlns:cup="http://contentservices.cambridge.org" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://cambridge.org/core/metadata" xmlns:core="http://cambridge.org/core" xmlns:c="http://cambridge.org/core/content" display="inline"> <mml:mrow> <mml:mrow> <mml:mo><</mml:mo> </mml:mrow> <mml:mn>0.01</mml:mn> <mml:mspace width="0.167em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">k</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> ), despite being numerous in mountain environments, are underrepresented in scientific inquiry when assessing their response to climate change. We present new insights into the vanishing (no visible surface ice whilst underlain by bedrock or water) of 77 very small glacierets distributed in the Northern and Central Andes of Chile. We also analyse the presumable vanishing (no visible surface ice whilst underlain by regolith) of 244 additional very small glacierets, comprising a total dataset of 321 very small glacierets within the study area, equivalent to the loss of 5.69 times 106 m 3 $5.69\times 10^6\,\mathrm{m}^3$ <mml:math xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:mnf="http://cambridge.org/core/manifest" xmlns:cup="http://contentservices.cambridge.org" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:m="http://cambridge.org/core/metadata" xmlns:core="http://cambridge.org/core" xmlns:c="http://cambridge.org/core/content" display="inline"> <mml:mrow> <mml:mn>5.69</mml:mn> <mml:mi>×</mml:mi> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> <mml:mspace width="0.167em"/> <mml:msup> <mml:mi>m</mml:mi> <mml:mn>3</mml:mn> </mml:msup> </mml:mrow> </mml:math> of water equivalent ice volume according to the 2022 Chilean Public Glacier Inventory. Our results show that 45.5% of the sample shrank from individually small glaciers at the beginning of the 21st century, whereas 53.0% of the sample vanished after being fragmented from larger glaciers in the same time span. The observed generalised reduction behaviour and vanishing results after extremely dry conditions at the end of the 2009–2022 Central Andes megadrought. We discuss our results in terms of the minimum area threshold for classifying very small glacierets, and whether their vanishing poses a hydrological impact.