What is the current state of Chilean glaciers?

The trend in glacier mass balance in Chile is similar to that in most parts of the world: declining glacier area and retreat and disappearance of many small mountain glaciers ¹. Chile is a typically understudied region of the world’s glacier monitoring project ², even though it possesses ~75-80% of the total glacier area of South America. Nevertheless, an increasing amount of studies have appeared within recent years, providing updates on the health of glaciers across Chile ^3,4,5,6,7. Providing a spatially complete overview of the current state of all glaciers in the country is difficult because there are too many glaciers to measure in person. Information that is available comes from different ways of measuring the glacier (using reference ‘stakes’ or from satellite observations, for example) and typically happens over different years in different studies. A review of the recent literature demonstrates that glaciers are mostly all losing mass (becoming thinner and shrinking) and that some of the largest changes are occurring in Patagonia. Within the whole of South America, the calculated loss of glacier ice between 2000 and 2015 was almost 20 gigatons per year (A gigaton equals to one (10⁹) billion tons), around 83% of which occurred in Patagonia (Figure 1) ³.

Figure 1. Measured glacier mass balance of all glaciers in South America between 2000-2015 with german satellite TanDEM-X. The left panel is the yearly balance of accumulation and melting of ice in metres of water equivalent per year. The right panel is the same area but for total mass (weight) of the glacier change in gigatons per year. (Source: Braun et al., 2019) ³

Changes in the central and desert Andes of Chile are typically much smaller, mainly due to much smaller glacier sizes that are less dynamic (e.g. are not losing ice to the water). However, many of these glaciers are still losing a lot of ice relative to their size and undergoing a general decline in mass, especially under extended drought periods ⁸. Studies such as on Bello and Yeso glaciers ⁴, and Echaurren Norte glacier ⁵ (which has one of the longest records of mass balance on the continent ²), show similar effects within the region over the last decades (Figure 2 and Figure 3), partially in response to the El Niño Southern Oscillation (ENSO). Rates of ice loss are calculated in the range of 0.7 metres of water equivalent per year from these small glaciers since records began in the 1950’s, but are notably greater (1.2 metres of water equivalent per year or more) under a prolonged drought that has been occurring since 2010 ⁵.

Figure 2. Modelled (lines) and measured (dots) surface elevation change on glaciers of the Río Yeso Basin (Cajón del Maipo) 2000-2015. (Source: Burger et al., 2018) ⁴

Figura 3. Measured mass balance (dots) of Echaurren Norte Glacier, Cajon del Maipo in years 1975-2015. Colours red and blue indicate El Niño and La Niña years, respectively. (Source: Farias-Barahona et al., 2019) ⁵

In the south, glaciers like the famous Grey Glacier are losing similar amounts of ice per year (1.05 metres water equivalent per year) while Tyndall Glacier is notably more (~2.6 metres per year) ⁷. In general it’s bad news for the country’s glaciers, and such loss of ice has some potentially serious implications. However, there are some notable exceptions to the trend, such as the growth of the Pío XI Glacier in O’Higgins National Park and the stable grounding position of the well-known Perito Moreno Glacier in Argentina. The future state of Chilean glaciers as a whole is set to continue along this downward trend of melt and decay under a warming world, however, which has been breaking several records at the time of writing ^9,10.

Cited information:

¹ IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.
² WGMS (2017, updated, and earlier reports): Global Glacier Change Bulletin No. 2 (2014-2015). Zemp, M., Nussbaumer, S. U., Gärtner-Roer, I., Huber, J., Machguth, H., Paul, F., and Hoelzle, M. (eds.), ICSU(WDS)/IUGG(IACS)/UNEP/UNESCO/WMO, World Glacier Monitoring Service, Zurich, Switzerland, 244 pp., based on database version: doi:10.5904/wgms-fog-2018-11. Available at: https://wgms.ch/faqs/
³ Braun, M. H., Malz, P., Sommer, C., Farías-Barahona, D., Sauter, T., Casassa, G., … Seehaus, T. C. (2019). Constraining glacier elevation and mass changes in South America. Nature Climate Change, 9(FEBRUARY). https://doi.org/10.1038/s41558-018-0375-7
⁴ Burger, F., Ayala, A., Farias-Barahona, D., Shaw, T. E., Macdonell, S., Brock, B., McPhee, J., Pellicciotti, F. (2018). Interannual variability in glacier contribution to runoff from a high ‐ elevation Andean catchment: understanding the role of debris cover in glacier hydrology. Hydrological Processes, SI-Latin(January), 1–16. https://doi.org/10.1002/hyp.13354
⁵ Farias-Barahona, D., Casassa, G., Schaefer, M., Burger, F., Seehaus, T., Iribarren-Anacona, P., … Braun, M. H. (2019). Geodetic Mass Balances and Area Changes of Echaurren Norte Glacier ( Central Andes , Chile ) between 1955 and 2015. Remote Sensing, 11(260), 1–17. https://doi.org/10.3390/rs11030260
⁶ Schaefer, M., Rodriguez, J. L., Scheiter, M., & Casassa, G. (2017). Climate and surface mass balance of Mocho Glacier , Chilean Lake District , 40 ° S. Journal of Glaciology, 63, 218–228. https://doi.org/10.1017/jog.2016.129
⁷ Weidemann, S. S., Sauter, T., Malz, P., Jaña, R., Arigony-neto, J., Casassa, G., & Schneider, C. (2018). Glacier Mass Changes of Lake-Terminating Grey and Tyndall Glaciers at the Southern Patagonia Icefield Derived From Geodetic Observations and Energy and Mass Balance Modeling. Frontiers in Earth Science, 6(June), 1–16. https://doi.org/10.3389/feart.2018.00081
⁸ Garreaud, R. D., Alvarez-Garreton, C., Barichivich, J., Pablo Boisier, J., Christie, D., Galleguillos, M., … Zambrano-Bigiarini, M. (2017). The 2010-2015 megadrought in central Chile: Impacts on regional hydroclimate and vegetation. Hydrology and Earth System Sciences, 21(12), 6307–6327. https://doi.org/10.5194/hess-21-6307-2017
⁹ “July on course to be hottest month ever, say climate scientists” (2019) The Guardian [on-line] Available at: https://www.theguardian.com/environment/2019/jul/16/july-on-course-to-be-hottest-month-ever-say-climate-scientists (last access 31/07/2019)
¹⁰ “’No doubt left’ about scientific consensus on global warming, say experts” (2019) The Guardian [on-line] Available at: https://www.theguardian.com/science/2019/jul/24/scientific-consensus-on-humans-causing-global-warming-passes-99 (last access 31/07/2019)

Written by Thomas Shaw.
Edited by Equipo Glaciar.