Drastic glacier retreat at Pico de Orizaba (19º N, Mexico) since the Little Ice Age

<p>The Little Ice Age (LIA) occurred between CE 1250 and 1850 and is considered a period of moderate cold conditions, especially recorded in the northern hemisphere. Numerous recent studies provide robust evidence of glacier advances worldwide during the LIA and a dramatic retreat since then. These studies combined investigation of moraine records, paintings, topographical and glaciological measurements as well as multitemporal aerial and terrestrial photographs and satellite images. For instance, post-LIA glaciers retreat amounts ~60 % in the Alps (Paul et al., 2020), ~88 % in the Pyrenees (Rico et al., 2016) and 89 % in the Bolivian Andes (Ramírez et al., 2001). However, there is scarce knowledge in Mexico about the glacier changes since the LIA. The reconstructions are limited to the Iztaccíhualt volcano where Schneider et al. (2008) established a glacier retreat of 95 %.</p><p>Here, we reconstruct the glacier evolution since the LIA to CE 2015 of the Mexican highest ice-capped volcano: Pico de Orizaba (19° 01´ N, 97° 16´W, 5,675 m a.s.l.). Due to Pico de Orizaba is in the outer Tropic, the most plausible scenario is a glacier evolution similar to the Bolivian Andes and especially to the Iztaccíhualt volcano. To carry out this research, we mapped the glacier area during the LIA, based on moraine record, and the area during 1945, 1958, 1971, 1988, 1994, 2003 and 2015 using a previous map elaborated by Palacios and Vázquez-Selem (1996), aerial orthophotographs and satellite images. The geographical mapping and the calculus of area, minimum altitude and volume of the glacier were generated with the software ArcGIS 10.2.2. The results show that glacier area retreated 92% between the LIA (8.8 km<sup>2</sup>) and 2015 (0.67 km<sup>2</sup>), being a drastic glacier loss in agreement with the Bolivian Andes and Iztaccíhualt. Therefore, mexican glaciers have experienced the major shrunk since LIA that implies a highly sensitive reaction to global warming.</p><p>This research was supported by the Project UNAM-DGAPA-PAPIIT grant IA105318.</p><p>References</p><p>Palacios, D., Vázquez-Selem, L. 1996. Geomorphic effects of the retreat of Jamapa glacier, Pico de Orizaba volcano (Mexico). Geografiska Annaler, Series A, Physical Geography 78, 19-34.</p><p>Paul F., Rastner P., Azzoni R.S., Diolaiuti G., Fugazza D., Le Bris R., Nemec J., Rabatel A., Ramusovic M., Schwaizer G., and Smiraglia C. 2020. Glacier shrinkage in the Alps continues unabated as revealed by a new glacier inventory from Sentinel-2 https://doi.org/10.5194/essd-2019-213.</p><p>Ramírez, E., Francou, B., Ribstein, P., Descloitres, M., Guérin, R., Mendoza, J., Gallaire, R., Pouyaud, B., Jordan, E. 2001. Small glaciers disappearing in the tropical Andes: a case study in Bolivia: Glaciar Chacaltaya (16° S). Journal of Glaciology 47 (157), 187-194.</p><p>Rico I., Izagirre E., Serrano E., López-Moreno J.I., 2016. Current glacier area in the Pyrenees : an updated assessment 2016. Pirineos 172, doi: http://dx.doi.org/10.3989/Pirineos.2017.172004.</p><p>Schneider, D., Delgado-Granados, H., Huggel, C., Kääb, A. 2008. Assessing lahars from ice-capped volcanoes using ASTER satellite data, the SRTM DTM and two different flow models: case study on Iztaccíhuatl (Central Mexico). Natural Hazards and Earth System Sciences 8, 559-571.</p><p> </p><p> </p>