Imagine this; One day, Earth’s climate will suddenly change. Ocean circulation changes without warning, causing weather chaos. In the blink of an eye, Earth found itself in another ice age. Sounds like the script of a Hollywood disaster movie, right? What deserves more attention is that this is not a fictional scenario. This actually happened several times during the last Ice Age, which ended 11,000 years ago.
Turning points of the world climate
To provide new insight into these dramatic changes, researchers analyzed ice cores collected in Greenland. The cores contained data going back 120,000 years, including evidence of sudden climate shocks called Dansgaard-Eschger events.
They represent “tipping points” of the Earth’s climate. Imagine a person standing on the edge of a cliff. One wrong step will lead them into a dangerous abyss. This is a turning point.
“It’s really important to understand these turning points in climate because they can lead to catastrophic and irreversible changes,” said Christo Buizert, an associate professor in the School of Earth, Ocean and Atmospheric Sciences at Oregon State University.
What is the Dansgaard-Oschger cycle?
The Dansgaard-Ochger cycle is an example of rapid climate fluctuations that occurred more than 25 times during the last ice age. It’s like turning it on and off several times. The catalyst for these cycles is the Atlantic Meridional Overturning Circulation (AMOC), which circulates water in the Atlantic Ocean. This includes the Gulf Stream, which carries warm tropical waters to the North Atlantic.
“AMOC is fundamentally unstable, and when it breaks down, big things happen all over the world. “There is significant cooling in Europe and around the North Atlantic, and the Indian and Asian monsoons are decreasing,” Buizert said.
“This instability was common during the last ice age. This is worrying for the future, as climate models suggest the AMOC will weaken again due to global warming, potentially affecting billions of people.”
Climate of the last ice age
Buizert, a paleoclimatologist, used ice cores as time capsules to unravel and understand past climate changes. The cores contain water, dust, and tiny air bubbles containing hundreds of thousands of years of data. These data contain important data about the evolution of Earth’s atmosphere and help scientists understand past climate events.
Buizert analyzed ice cores from all over Greenland; this includes ice cores from southern and eastern Greenland, which have not been studied in detail. Findings regarding AMOC and winter sea ice interactions have increased interest in cores.
These interactions played an important role in the Dansgaard-Oschger events. Previously, scientists believed this was sea ice in the North Sea north of Iceland. The new analysis shows that winter sea ice spread much further south, reaching as far as modern-day France and New York.
“The model shows that the North Seas alone would not be large enough to cause climate change of this magnitude,” Buizert said. he said. “Not strong enough.”
Ice Age and Future Climate Change
The AMOC has been stable for the last 11,700 years. However, current climate conditions and predictions show that it may weaken again for reasons different from those of the ice age.
“We know AMOC will weaken, but will it collapse? This is a big question. The weakening is likely to be gradual for now, but it could cross a tipping point and catalyze drastic climate changes similar to those we’ve seen in the past,” Buizert said. “Climate does not behave linearly; It can change rapidly and irreversibly.”
The past holds the key to our future. The research was conducted in collaboration with scientists from five countries with support from the National Science Foundation. This knowledge brings us closer to understanding the nature of our planet’s climate. The study is a reminder that we still have much to learn, research and prepare for climate change. The study was published in the journal Proceedings of the National Academy of Sciences.
Source: Port Altele
