The case of a southern European glacier disappearing under recent warming that survived Roman and Medieval warm periods

Abstract

<jats:p>Abstract. Mountain glaciers have generally experienced an accelerated retreat over the last three decades as a rapid response to current global warming. However, the response to previous warm periods in the Holocene is not well-described for glaciers of the of southern Europe mountain ranges, such as the Pyrenees. The situation during the Medieval Climate Anomaly (900–1300 CE) is particularly relevant since it is not certain whether the glaciers just experienced significant ice loss or whether they actually disappeared. We present here the first chronological study of a glacier located in the Central Pyrenees (N Spain), the Monte Perdido Glacier (MPG), carried out by different radiochronological techniques and their comparison with geochemical proxies with neighboring paleoclimate records. The result of the chronological model proves that the glacier endured during the Roman Period and the Medieval Climate Anomaly. The lack of ice from last 600 years indicates that the ice formed during the Little Ice Age has melted away. The analyses of the content of several metals of anthropogenic origin, such as Zn, Se, Cd, Hg, Pb, appear in low amounts in MPG ice, which further supports our age model in which the record from the industrial period is lost. This study confirms the exceptional warming of the last decades in the context of last two millennia. We demonstrate that we are facing an unprecedented retreat of the Pyrenean glaciers which survival is compromised beyond a few decades. </jats:p>

Glacial Ice Age Shapes Microbiome Composition in a Receding Southern European Glacier

“…Glacial ice samples were cored in September 2017 as part of the PaleoICE EXPLORA project ( Moreno et al, 2021 ). A summary of the overall experimental strategy is represented in Supplementary Figure 1 .…”

“…Ice chronology along the sampled transect was established elsewhere ( Moreno et al, 2021 ) by a combination of different radiometric, including 210 Pb, 137 Cs, 14 C, and water-insoluble organic carbon (WIOC) technique. Additionally, this absolute chronology was evaluated by the comparison with a nearby paleoenvironmental reconstruction obtained from Marboré Lake where anthropogenic metals (Zn, Se, Cd, Hg, Pb) were measured.…”

“…Additionally, this absolute chronology was evaluated by the comparison with a nearby paleoenvironmental reconstruction obtained from Marboré Lake where anthropogenic metals (Zn, Se, Cd, Hg, Pb) were measured. Through this comparison, it was evident the lack of ice from the Industrial Era and, eventually, a depth-age model was established ( Moreno et al, 2021 ).…”

“…Thus, it is necessary to study them before they disappear completely. A recent study ( Moreno et al, 2021 ) presents the chronology of MPG (∼0–1,200 years CE), which is located in the north face of the Monte Perdido peak in Ordesa y Monte Perdido National Park, Spain (42∘40′50″N; 0∘02′15″E; 3355 m a.s.l.) ( Figure 1 ).…”

“…In the present paper, we deepen our knowledge of the microbial populations that inhabit the glacier ice (using samples obtained along an altitudinal transect covering most of the preserved ice sequence, Figure 1B ); and we compare the distribution of these populations with the chemical characteristics of the ice samples. Additionally, we establish a comparison of the populations in relation to the age of the samples, which had previously been dated ( Moreno et al, 2021 ).…”