Climate trends and glacier retreat in the Cordillera Blanca, Peru, revisited

Abstract

The total glacial area of the Cordillera Blanca, Peru, has shrunk by more than 30% in the period of 1930 to the present with a marked glacier retreat also in the recent decades. The aim of this paper is to assess local air temperature and precipitation changes in the Cordillera Blanca and to discuss how these variables could have affected the observed glacier retreat between the 1980s and present. A unique data set from a large number of stations in the region of the Cordillera Blanca shows that after a strong air temperature rise of about 0.31°C per decade between 1969 and 1998, a slowdown in the warming to about 0.13°C per decade occurred for the 30 years from 1983 to 2012. Additionally, based on data from a long-term meteorological station, it was found that the freezing line altitude during precipitation days has probably not increased significantly in the last 30 years. We documented a cooling trend for maximum daily air temperatures and an increase in precipitation of about 60 mm/decade since the early 1980s. The strong increase in precipitation in the last 30 years probably did not balance the increase of temperature before the 1980s. It is suggested that recent changes in temperature and precipitation alone may not explain the glacial recession within the thirty years from the early 1980s to 2012. Glaciers in the Cordillera Blanca may be still reacting to the positive air temperature rise before 1980. Especially small and low-lying glaciers are characterised by a serious imbalance and may disappear in the near future.

Comparing peasants' perceptions of precipitation change with precipitation records in the tropical Callejón de Huaylas, Peru

“…We have not investigated thermal conditions but the perceived increase in the frequency of ground frosts in the early growing season (as stated by some farmers) contradicts increasing (minimum) temperatures as reported by Schauwecker et al (2014) or in Vuille et al (2015). The increases in minimum temperatures are reported to be most pronounced in the dry and early wet season.…”

“…For Recuay , the date is typically in September or early October with the earliest onset calculated for 13 August (1988) and the latest for 20 November (1972), the arithmetic mean value being 23 September. For 1991, no onset of the wet season could be calculated as there was an unusual dry period from autumn 1991 to spring 1992 (also described by Schauwecker et al, 2014). For Huaraz (1996-2012) the onset day occurred typically 5 days later than in Recuay with a mean value centered on 28 September, the earliest day being 4 September (2001), the latest 25 October (2011).…”

“…While the tropical atmosphere is thermally homogeneous, the region is characterized by single-peaked hygric seasonality. Precipitation increases from August towards the October to April core wet season and is close to nil during June and July (e.g., Kaser and Osmaston, 2002;Mark et al, 2010;Schauwecker et al, 2014). Dry season runoff, and thus water supply, is comprised of up to two thirds glacial melt water from the Cordillera Blanca (e.g., Baraer et al, 2012;Kaser et al, 2010;Seltzer, 2003, 2005).…”

Un análisis comparativo del comportamiento diferencial de los glaciares en los Andes Tropicales usando teledetección

“…SCHAUWECKER et al (2014) observaron un incremento del calentamiento de 0,31°C/ década entre 1969 y 1998, mientras el calentamiento se desaceleró a 0,13°C/ década de 1983 y 2012 en la Cordillera Blanca, y recientemente, VEETTIL et al (2016b) también observaron condiciones similares. Una pequeña disminución en la precipitación se observa cerca del Nevado Tuco, en particular durante JJA, de las últimas seis décadas, así como un ligero aumento en la precipitación DEF entre 2000 y 2010 (VEETTIL et al 2016b).…”

“…El retroceso discontinuo de los glaciares andinos tropicales desde la Pequeña Edad de Hielo (PEH) en Ecuador, Perú y Bolivia provee una estimación de las fluctuaciones climáticas desde principios del siglo XVII (VUILLE et al 2008). En un estudio reciente, SCHAUWECKER et al (2014) observaron un aumento en la temperatura del aire de aproximadamente 0,31ºC/ década entre 1969 y 1998 y 0,13ºC/década de 1983 y 2012 en la Cordillera Blanca de Perú. Este pequeño descenso en el ritmo de calentamiento en las últimas décadas es más visible cerca de la costa del Pacífico mientras que regiones de gran elevación en los Andes tropicales siguen en aumento (VUILLE et al 2015).…”