Why are glaciers important?

Glaciers are a globally important part of the natural water cycle (Figure 1) and the balance of energy. Normally glaciers receive the most news headlines related to big events at large scales in Greenland and Antarctica. These events are crucially important to the future of low-lying communities around the world because loss of glacier ice contributes to an increasing average elevation of the sea level. In fact estimates of up to 20 cm average sea level rise are expected from warming scenarios of climate change by the end of the 21st Century ^1,2. This might not sound like a lot, but when we consider the number of people whose livelihoods are at current sea levels, the impacts become severe and costly!

Figure 1. A scheme for the simplified water cycle annotated to show human industries and reliance upon glacier water. Source: adapted from Osslan Vergara.

In Chile, total contributions to sea level rise are generally small in comparison to these big ice sheets at the poles, but even contributions from the Patagonian ice fields have been estimated up to 10% of the total between the years in the last half Century ³. Regardless, the effect of a rising sea level will still impact coastal communities of Chile with local estimates up to 74 cm for 2100 in a worst case scenario ⁴.

Figure 2. Coastal sea level rise for 2100 according to a RCP 8,5 scenario. Source: adapted from Kopp et al. (2017) ².

Considering the current state of mountain glaciers and climate in Chile, their contributions to streamflow are vital! This is because they can provide important reserves of water to 1) major cities (Santiago being the most obvious example), 2) agriculture, 3) hydropower production, and 4) mining and other industries. The news that ~55% of Chile’s exports come from raw or refined copper (Figure 2) ⁵ is probably well known to most of the people reading this. However, the contributions of small mountain glaciers in the central and northern parts of Chile that provide water to support the extraction and production of these minerals is perhaps not. Estimates of glacier contributions to the summer streamflow and basins in central Chile is up 50-60% in dry years with little snow ⁶ and this is likely to increase as the region experiences a sustained period of serious drought ⁷.

Figure 3. Chile’s export summary as generated by the Economic Complexity Observatory: https://atlas.media.mit.edu/es/

Equally, foodstuffs and production of wines are sizeable contributions to Chile’s exports (Just think of all that Casillero del Diablo being drunk in the US and Europe!) and these are equally sensitive to the availability of water which is generally decreasing for many regions of country. Therefore, glaciers hold a much greater socio-economic importance both in Chile and the world than many of us may realize.

Next time you open your water tap or take a shower, think that some of that precious H₂O could be sourced from our friendly frozen rivers.

Cited information:

¹ Church, J.A., P.U. Clark, A. Cazenave, J.M. Gregory, S. Jevrejeva, A. Levermann, M.A. Merrifield, G.A. Milne, R.S. Nerem, P.D. Nunn, A.J. Payne, W.T. Pfeffer, D. Stammer and A.S. Unnikrishnan, 2013: Sea Level Change. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
² Kopp, R. E., Deconto, R. M., Bader, D. A., Hay, C. C., Radley, M., Kulp, S., … Strauss, B. H. (2017). Evolving Understanding of Antarctic Ice-Sheet Physics and Ambiguity in Probabilistic Sea-Level Projections Earth’s Future., 5, 1217–1233.
³ Glasser, N. F., Harrison, S., Jansson, K. N., Anderson, K., & Cowley, A. (2011). Global sea-level contribution from the Patagonian Icefields since the Little Ice Age maximum. Nature Geoscience, 4(5), 303–307. https://doi.org/10.1038/ngeo1122
Rignot, E., Rivera, A., & Casassa, G. (2003). Contribution of the Patagonia Icefields of South America to Sea Level Rise. Science, 302(OCTOBER), 434–438.
⁴ Albrecht, F. & Shaffer, G. (2016). Regional Sea-Level Change along the Chilean Coast in the 21st Century. Journal of Coastal Research: Volume 32, Issue 6: pp. 1322 – 1332.
⁵ Simoes A.J.G. & Hidalgo,C.A. (2011) The Economic Complexity Observatory: An Analytical Tool for Understanding the Dynamics of Economic Development. Workshops at the Twenty-Fifth AAAI Conference on Artificial Intelligence. https://atlas.media.mit.edu/es/ (Last access on 14/03/2019)
⁶ Burger, F., Ayala, A., Farias, 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
⁷ 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

Written by Thomas Shaw.
Edited by Equipo Glaciar.