¿Por qué los glaciares son importantes?
Los glaciares son una parte importante, a nivel mundial, del ciclo natural del agua (Figura 1) y el balance de energía. Normalmente, los glaciares reciben la mayoría de los titulares de noticias relacionados con grandes eventos a gran escala en Groenlandia y la Antártida. Estos eventos son de crucial importancia para el futuro de las comunidades costeras en todo el mundo porque la pérdida de hielo en los glaciares contribuye a un aumento promedio del nivel del mar. De hecho, se esperan estimaciones de hasta 20 cm de aumento promedio del nivel del mar a partir de los escenarios de calentamiento del cambio climático para fines del siglo XXI 1,2. Esto puede no parecer mucho, pero cuando consideramos la cantidad de personas cuyos medios de vida se encuentran en los niveles actuales del mar, ¡los impactos se vuelven severos y costosos!.
Figura 1. Un esquema para el ciclo del agua simplificado indicando las industrias humanas y la dependencia del agua del glaciar. Fuente: adaptado de Osslan Vergara.
En Chile, las contribuciones totales al aumento del nivel del mar son generalmente pequeñas en comparación con las grandes capas de hielo en los polos, pero incluso las contribuciones de los campos de hielo patagónicos se han estimado de hasta un 10% del total desde 1960 3. Independiente de ello, el efecto del aumento del nivel del mar igualmente afectará a las comunidades costeras de Chile, con estimaciones locales de hasta 74 cm para el 2100 en el peor de los casos 4.
Figura 2. Aumento del nivel del mar costero para el año 2100 según un escenario RCP 8,5. Fuente: adaptado de Kopp et al. (2017) 2.
Teniendo en cuenta el estado actual de los glaciares de montaña y el clima en Chile, ¡sus contribuciones al flujo de agua son vitales! Esto se debe a que pueden proporcionar importantes reservas de agua a 1) ciudades importantes (Santiago es el ejemplo más obvio), 2) agricultura, 3) producción de energía hidroeléctrica y 4) minería y otras industrias. La noticia de que el ~55% de las exportaciones de Chile provienen de cobre crudo o refinado (Figura 2) 5 es probablemente bien conocida por la mayoría de las personas que leen esto. Sin embargo, las contribuciones de los pequeños glaciares de montaña en el norte y centro de Chile, que proveen agua para apoyar la extracción y producción de estos minerales, quizás no sean bien conocidas. Las estimaciones de las contribuciones de los glaciares al flujo hídrico en verano y las cuencas en el centro de Chile aumentaron en un 50-60% en años secos con poca nieve 6, y es probable que esto aumente a medida que la región experimente un período sostenido de sequía 7.
Figura 3. Resumen de exportación de Chile generado por el Observatorio de Complejidad Económica: https://atlas.media.mit.edu/es/
Igualmente, los productos alimenticios y la producción de vinos son importantes contribuciones a las exportaciones de Chile (¡solo piense en todo lo que Casillero del Diablo abastece a las góndolas de los Estados Unidos y Europa!) y son igualmente sensibles a la disponibilidad de agua, que en general está disminuyendo en muchas regiones del país. Por lo tanto, los glaciares tienen una importancia socioeconómica mucho mayor, tanto en Chile como en el mundo, de lo que muchos de nosotros podemos darnos cuenta.
La próxima vez que abra su grifo de agua o tome una ducha, piense que parte de ese precioso H2O podría venir de nuestros amigables ríos de hielo.
Información citada:
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
Escrito por Thomas Shaw.
Editado por Equipo Glaciar.
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.