Evidence for a little ice age and recent warming from a borehole temperature data inversion procedure

2004 ◽  
Vol 96 (10) ◽  
pp. 5841-5844
Author(s):  
J. Fivez ◽  
J. Thoen
2017 ◽  
Vol 37 ◽  
pp. 1257-1266 ◽  
Author(s):  
Tomi P. Luoto ◽  
E. Henriikka Kivilä ◽  
Marttiina V. Rantala ◽  
Liisa Nevalainen

2001 ◽  
Vol 47 (159) ◽  
pp. 579-588 ◽  
Author(s):  
L. A. Rasmussen ◽  
H. Conway

AbstractA simple flux model using twice-daily measurements of wind, humidity and temperature from standard upper-air levels in a distant radiosonde estimated winter balance of South Cascade Glacier, Washington, U.S.A., over 1959–98 with error 0.24 m w.e. Correlation between net and winter balance is strong; the model estimates net balance with error 0.53 m w.e. Over the past 40 years, average net balance of South Cascade Glacier has been strongly negative (−0.46 m w.e.), and it has been shrinking steadily. In comparison, 200 km west-southwest at Blue Glacier, the average balance has been less negative (−0.13 m w.e); that glacier has undergone little change over the 40 years. Balance histories of the two glaciers are positively correlated (r = +0.54), and South Cascade has been more out of balance than Blue, presumably because it is still adjusting to climate change since the Little Ice Age. Recent warming and drying has made the net balance of both glaciers strongly negative since 1976 (−0.84 m w.e. at South Cascade, −0.56 m w.e. at Blue). If South Cascade Glacier were in balance with the 1986–98 climate, it would be about one-quarter of its present area.


Botany ◽  
2021 ◽  
Author(s):  
Connor King ◽  
Neal Michelutti ◽  
Carsten Meyer-Jacob ◽  
Richard Bindler ◽  
Pedro Tapia ◽  
...  

Recent warming in the Andes is affecting the region’s water resources including glaciers and lakes, which supply water to tens of millions of people downstream. High altitude wetlands, known locally as bofedales, are an understudied Andean ecosystem despite their key role in carbon sequestration, maintaining biodiversity, and regulating water flow. Here, we analyze subfossil diatom assemblages and other siliceous bioindicators preserved in a peat core collected from a bofedal in Peru’s Cordillera Vilcanota. Basal radiocarbon ages show the bofedal likely formed during a wet period of the Little Ice Age (1520-1680 CE), as inferred from nearby ice core data. The subfossil diatom record is marked by several dynamic assemblage shifts documenting a hydrosere succession from an open-water system to mature peatland. The diatoms appear to be responding largely to changes in hydrology that occur within the natural development of the bofedal, but also to pH and possibly nutrient enrichment from grazing animals. The rapid peat accretion recorded post-1950 at this site is consistent with recent peat growth rates elsewhere in the Andes. Given the many threats to Peruvian bofedales including climate change, overgrazing, peat extraction, and mining, these baseline data will be critical to assessing future change in these important ecosystems.


2021 ◽  
Vol 4 (1) ◽  
pp. 140-147
Author(s):  
Valiya Hamza ◽  
Fábio Vieira ◽  
Suze Guimaraes ◽  
Elizabeth Pimentel

Estimates have been made of ground surface temperature (GST) variations for 25 localities in the region of Manaus (province of Amazon in Brazil) making use of both forward and inverse models. The work is based on analysis of borehole temperature logs as well as remote sensing data concerning changes in vegetation cover. Results of functional space inversion (FSI) of borehole temperature data reveal the occurrence of a cooling event, with a decrease in temperature of slightly less than 1oC, for the period of 1600 to 1850 AD. This episode coincides roughly with the period of “little ice age” in the southern hemisphere. It was followed by a warming event, with magnitudes varying from 2 to 3oC, that lasted until recent times. Integration of these results with estimates based on changes in normalized index of vegetation cover (NVDI) of the last decade points to continuation of climate warming over the last decade. This event is found to be prominent in areas of deforestation in central parts of the Amazon region.


2020 ◽  
Author(s):  
Ana Moreno ◽  
Miguel Bartolomé ◽  
Juan Ignacio López-Moreno ◽  
Jorge Pey ◽  
Pablo Corella ◽  
...  

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.


2021 ◽  
Vol 15 (2) ◽  
pp. 1157-1172
Author(s):  
Ana Moreno ◽  
Miguel Bartolomé ◽  
Juan Ignacio López-Moreno ◽  
Jorge Pey ◽  
Juan Pablo Corella ◽  
...  

Abstract. Mountain glaciers have generally experienced an accelerated retreat over the last 3 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 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 southern European 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 (NE Spain), Monte Perdido Glacier (MPG), carried out by different radiochronological techniques and a comparison with geochemical proxies from neighbouring palaeoclimate records. The chronological model evidences that the glacier persisted during the Roman period and the Medieval Climate Anomaly. The apparent absence of ice in the past ∼ 600 years suggests that any ice accumulated during the Little Ice Age has since ablated. This interpretation is supported by measured concentrations of anthropogenic metals, including Zn, Se, Cd, Hg and Pb, which have concentrations well below those typical of industrial-age ice measured at other glaciers in Europe. This study strengthens the general understanding that warming of the past few decades has been exceptional for the past 2 millennia.


2014 ◽  
Vol 96 ◽  
pp. 1-7 ◽  
Author(s):  
Lalla Amina Ouzzaouit ◽  
Alae Bakraoui ◽  
Nouredine Benalioulhaj ◽  
Julio Carneiro ◽  
Antonio Correia ◽  
...  

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