1,000 years of glacial ice reveal 'prosperity and peril' in Europe
Evidence preserved in glaciers provides continuous climate and vegetation records during major historical events

Date:
November 3, 2021
Source:
American Geophysical Union
Summary:
Europe's past prosperity and failure, driven by climate changes,
has been revealed using thousand-year-old pollen, spores
and charcoal particles fossilized in glacial ice. This first
analysis of microfossils preserved in European glaciers unveils
earlier-than-expected evidence of air pollution and the roots of
modern invasive species problems.



FULL STORY ========================================================================== Europe's past prosperity and failure, driven by climate changes,
has been revealed using thousand-year-old pollen, spores and charcoal
particles fossilized in glacial ice. This first analysis of microfossils preserved in European glaciers unveils earlier-than-expected evidence
of air pollution and the roots of modern invasive species problems.


==========================================================================
A new study analyzed pollen, spores, charcoal and other pollutants frozen
in the Colle Gnifetti glacier on the Swiss and Italian border. The
research found changes in the composition of these microfossils
corresponded closely with known major events in climate, such as the
Little Ice Age and well-established volcanic eruptions.

The work was published in Geophysical Research Letters, which publishes
high- impact, short-format reports with immediate implications spanning
all Earth and space sciences.

The industrialization of European society also appeared clearly
in the microfossil record and, in some cases, showed up sooner than
expected. Pollen from the introduction of non-native crops was found to
go back at least 100 years ago and pollution from the burning of fossil
fuels shows up in the 18th century, about 100 years earlier than expected.

Existing historical sources such as church records or diaries record
conditions during major events like droughts or famines. However, studying
data from the glaciers contributes to the understanding of climate and
land use surrounding such events, providing non-stop context for them
with evidence from a large land area. Precisely identifying the timing of
these events can help scientists better understand current climate change.

"The historical sources that were available before, I don't think [the
sources] got the full picture of the environmental context," said Sandra Brugger, a paleoecologist at the Desert Research Institute in Nevada and
lead researcher on the study. "But also, with the ice core, we couldn't
get the full picture until we started collaborating with historians on
this. It needs those two sides of the coin." Evidence on high The new
study analyzed microfossils frozen in two 82- and 75-meter-long ice cores pulled from the Colle Gnifetti glacier, which are the first two ice cores
from the continent of Europe studied for microfossils. Similar studies
have sampled ice cores in South America, Central Asia and Greenland,
but those regions lack the breadth of written historical records that can
be directly correlated with the continuous microfossil data in ice cores.

Over the centuries, wind, rain and snow carried microfossils from
European lowlands, the United Kingdom and North Africa to the exposed
glacier. Ice in this glacier site dates back tens of thousands of years,
and the altitude of Colle Gnifetti -- 4,450 meters above sea level --
means the ice was likely never subjected to melting, which would mix the
layers of samples and create uncertainty in the chronology of the record.

"They can actually pinpoint and identify the relationships between what's happening on the continent with climatic records inherent in the ice,"
said John Birks, a paleoecologist at the University of Bergen who was
not associated with the study. "They can develop, in a stronger way, this
link between human civilization and change and climate, particularly in
the last thousand years or so where conventional pollen analysis is rather weak." Evidence of pollution due to fossil fuel combustion also appeared earlier in the chronological record than expected. The researchers found evidence of the early burning of coal in the United Kingdom around 1780,
much earlier than the expected onset of industrialization around 1850,
which could have implications for global climate change modeling.

The records also showed evidence of pollen from non-native European plants
from 100 years ago, showing a long legacy of the existing ecological
problems created by invasive species transported across continents
through trade.

========================================================================== Story Source: Materials provided by American_Geophysical_Union. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. S. O. Brugger, M. Schwikowski, E. Gobet, C. Schwo"rer, C. Rohr,
M. Sigl,
S. Henne, C. Pfister, T. M. Jenk, P. D. Henne, W. Tinner. Alpine
Glacier Reveals Ecosystem Impacts of Europe's Prosperity and Peril
Over the Last Millennium. Geophysical Research Letters, 2021; 48
(20) DOI: 10.1029/ 2021GL095039 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211103140143.htm

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