Comment on “Climate in the Western Cordillera of the Central Andes over the last 4300 years”, by Engel et al. (2014).
Sáez A, Giralt S, Hernández A, Bao R, Pueyo JJ, Moreno A, Valero-Garcés BL.
Quaternary Science Reviews 109, 126 -130.
Engel et al. (2014) present a new approach to understand Holocene climate changes in the Central Andes. They reconstruct the relative temperature changes in the Western Cordillera for the last 4300 years by characterizing the ?13C composition of a plant species occurring in the Carhuasanta peat sedimentary record (Peru, 15° 30? S). The authors were able to apply such innovative approach because no significant organic matter degradation was detected. A significant feature of their climatic reconstruction is the identification of up to 7 arid short events (Fig. 1). This new Holocene climate record is timely and welcome since it will help to better understand the centennial hydrological and temperature changes in the region. Engel et al. (2014) identify these 7 short arid events in other regional climatic reconstructions derived from lake sediments, speleothems, peat bog and ice cores from the Central Andes between 7 and 18°S. One of these regional climatic reconstructions is based on the concentration of dust particles in the Sajama ice core studied by Thompson et al. (1998). The rationale of their approach was that high dust concentrations indicate regional arid conditions (Thompson et al., 1998, Thompson et al., 2000). Fig. 1 clearly shows that only 4 of the Carhuasanta dry periods (B, C, E and G) match with the Sajama dust record, whereas 3 of them (A, D and F) do not have a clear counterpart in the ice core.