Repeated catastrophic emissions from western North America to the North Pacific have contributed, at least, to hemispheric scale changes in the last glacial period of the Earth’s climate. Science: discovers.
The discovery provides a new insight into the impact of rapidly melting ice flowing into the North Pacific on the planet’s climate. This was stated by Maureen Walchak, paleoclimatologist at the College of Earth, Ocean and Atmospheric Sciences, Oregon State University, lead author of the study.
“Understanding how the ocean has interacted with glacial ice in the past helps us predict what might happen next,” Valchak said.
The Cordillera glacier once covered much of North West America from Alaska to Washington, D.C., Montana. Radiocarbon dating records of marine sediments have revealed that recurrent episodes of emissions from this ice over the past 42,000 years were early events in a chain reaction of global climate change. These unrests led to changes in the deep ocean circulation and the retreat of ice cover in the North Atlantic.
The findings challenge theories that these massive, global riots originated in the North Atlantic: a rapid loss of ice from the Laurentian glacier, another massive ice sheet that covered Canada և the northern part of the United States, including the northeast, north-east, north-east. : The Lorentid ice loss is known as the Henrikh Incident.
“It simply came to our notice then. The data irrevocably say that the first to go is the ice of the Pacific Ocean, followed by Heinrich Events and other changes. “The Pacific Ocean is taking a hit,” Valtsak said. “This is a paradigm shift in our thinking about how these events are related.”
To gain an insight into the history of the North Pacific climate, an international team of researchers collected and analyzed sedimentary nuclei from the northern Gulf of Alaska that were removed by drilling as part of the International Ocean Exploration Program.
“It took me years to get these new insights. We mapped the seabed for the first time, restored short sediment cores in 2004, dug longer cores in 2013, and had 16 years of hard laboratory work involving several postgraduate courses. students, ”said Alan Mix, the project’s lead investigator and co-author of the article.
“This was a virtually unknown area when we first started; it now offers more detailed information about the changing oceans on the planet during the ice age,” said Mix, an associate professor of Earth Earth College and Atmospheric Sciences.
The researchers measured the radioactive isotopes of carbon using chronological acceleration events of the two particles and added detailed amounts of small rocks dumped by icebergs known as frozen fragments.
The team traced the source of the ice fragments before clearing the massive ice sheets from the Cordillera Glacier, which covered northern Washington, most of British Columbia, and southern Alaska about 70,000 to 17,000 years ago.
The dirty icebergs came out of the icy currents, moving north into the ocean currents, carrying, and finally dumping their loads of sand, gravel, and gravel, leaving a record of rapid ice retreat, like treasure buried deep in the sea.
The authors of this study called the landfills of this Alaskan iceberg “Siku Events”, in Inuit, the word ice. Combining the record for glacial debris with radiocarbon chronology, the big surprise was that Siku Events immediately preceded Henrikh’s events, which are a kind of ice clearing in the North Atlantic.
Scientists have been aware of the Heinrich events for more than 30 years, such as evidence of frozen debris in the North Atlantic Ocean, but the cause of those events has never been convincingly explained, researchers say.
It makes sense for the Pacific Ocean to be involved in major planetary changes, Mix said. The Pacific Ocean is connected to the rest of the world by large-scale atmospheric circulation, physically around Antarctica, as well as at high altitudes, through the Bering Strait, across the North Atlantic to the North Atlantic Ocean.
“The Pacific Ocean is the largest reservoir of heat, water and carbon dioxide, simply because of its large size,” he said. “It really’s an 800-pound gorilla at the Climate Beasts Zoo.”
Today, the ice off the coast of Alaska is mostly receding և may disappear during this century as the climate warms. Melting ice will be poured into the Pacific և Arctic, helping to raise sea levels, affecting the remains of fresh, dense salt water in the ocean, as it did in the past.
If current ice melts back to past patterns and occurs rapidly, it could lead to the retreat of distant glacial systems in the North Atlantic and Arctic.
“This is one reason why it is prudent to slow down heating by reducing our use of fossil fuels,” Mix said.
“The new findings are likely to boost interest in the North Pacific, an area that has not been as well explored as other parts of the planet,” Valchak said.
It is not clear why the Cordillera eruptions occurred. Researchers would also like to better understand the link between Cordilleran emissions and other climatic events.
“Why did the other ices respond to Cordillera’s retreat?” How fast do dominoes fall into this sequence of events? ” Valchak asked. These are some of the issues that the research team continues to explore.
Reference. “The Stage of Millennial Climate Change in the Pacific Atlantic” by Maureen H. Waltzak, Alan S. Mix, Ellen A. Haley, Tim Hobern, June Un Padman, Summer K. Pretorius, Andreas Schmidtner, Joseph ozef S. Stoner և Sarah D. Elle Ellers, 2020 November 6, Science:,
DOI: 10.1126 / science.aba7096:
Additional co-authors of the study are Andreas Schmidt, Joseph Joseph Stoner, Brian Hale; իս June Padman, OSU Earth, Ocean և College of Atmospheric Sciences. Ian Yangui You, who recently received his Ph.D. in Oregon; OS Alder from OSU և US Geological Survey; Summer Praetorius, formerly OSU and now US Geological Survey; Ellen Cowan of Appalachian State University; Stewart Fallon and L. Keith Fifield of: Australian National University; el Sara elle Ellers from the University of Central Missouri.
The study was supported by the National Science Foundation, the Australian Research Council, the Australia-New Zealand IODP Commission and the Australian American Association.