Past rapid warming levels in the Arctic associated with widespread
climate changes

Date:
August 20, 2020
Source:
University of Melbourne
Summary:
Using Greenland ice cores, new research is the first to confirm the
longstanding assumption that climate changes between the tropics
and the Arctic were synchronized during the last glacial period.



FULL STORY ========================================================================== Abrupt climate changes during the Last Glacial Period, some 115,000 to
11,700 years ago, happened at the same time across a region extending
from the Arctic to the Southern Hemisphere subtropics, new research
has revealed.


==========================================================================
The study, led by University of Melbourne PhD student Ellen Corrick
and published today in the journal, Science, found that rapid warming
events over Greenland were linked to simultaneous temperature increases
across continental Europe, and changes in rainfall in the Asian and
South American monsoon regions.

"Some of the largest and most abrupt climate changes in Earth's geological recent past occurred during the Last Glacial Period, a cold interval
that extended between 115,000 and 11,700 years ago," Ms Corrick said.

Greenland ice cores recorded more than 25 abrupt warming episodes during
this period. These so called 'Dansgaard-Oeschger events' were associated
with increases in air temperature over Greenland of up to 16DEGCelsius, sometimes in a matter of a few decades.

Researchers say the findings provide important information for testing numerical models used to predict future climate changes and demonstrate
that profound climate changes can occur simultaneously, highlighting
the unstable nature of the climate system.

Co-author, University of Melbourne Associate Professor Russell Drysdale,
said: "Demonstrating synchrony in the climate response across such a
broad region marks a major advance in the study of Dansgaard-Oeschger
events. It allows scientists to improve understanding of how the
events are propagated globally via the ocean and atmosphere system."
The research team, which involved scientists from Denmark, the UK,
Germany, China, France and Switzerland, collated 63 individual climate
records derived from stalagmites collected from caves across Europe,
Asia and South America.

The records represent over 20 years' worth of published research from scientific teams around the world.

Stalagmites -- a type of cave mineral formation -- preserve information
on regional temperature and rainfall as they grow. Crucially, they can
be dated very precisely, allowing the timing of climate events to be
compared between records from different regions.

University of Melbourne Geochronologist Dr John Hellstrom, said that
resolving the issue of timing has proved difficult because precisely
dated records of past climate are required to determine exactly when
the events took place.

"Such records are relatively rare, and it is only now that we have enough
high- quality records to actually answer the question of synchrony,"
Dr Hellstrom said.

According to co-author Professor Eric Wolff from the University of
Cambridge, the findings resolve a long-standing dilemma within the
paleoclimate community, who study ancient climates.

"They provide confirmation of a persistent but, until now, unsubstantiated assumption that climate changes between the tropics and the Arctic
were synchronous."

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


========================================================================== Journal Reference:
1. Ellen C. Corrick, Russell N. Drysdale, John C. Hellstrom, Emilie
Capron,
Sune Olander Rasmussen, Xu Zhang, Dominik Fleitmann, Isabelle
Couchoud, Eric Wolff. Synchronous timing of abrupt climate
changes during the last glacial period. Science, 2020 DOI:
10.1126/science.aay5538 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200820143830.htm

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