The climate tipping points that changed Earth during last ice age

A new study published in the Proceedings of the National Academy of Sciences has unveiled new insights into abrupt climate shifts that occurred during the last Ice Age.
Led by Christo Buizert, an associate professor at Oregon State University, the research analyzed multiple ice cores from Greenland, providing data spanning up to 1,20,000 years.
The study focuses on Dansgaard-Oeschger events, dramatic climate fluctuations that represent tipping points in Earth’s climate system.
These events, which occurred more than 25 times during the last Ice Age, were triggered by rapid changes in the Atlantic Meridional Overturning Circulation (AMOC), a crucial component of global ocean circulation.

The AMOC has been well-behaved over the last 11,700 years. (Photo: Getty)

Buizert emphasises the importance of understanding these tipping points, stating, “It is really important to understand such tipping points in the climate, because they may result in catastrophic and irreversible change”.
The research reveals that interactions between the AMOC and wintertime sea ice played a key role in these events.
Contrary to previous beliefs, the new data suggests that winter sea ice extended much farther south than initially thought, reaching as far as modern-day France and New York City.
Climate modeling indicates that the collapse of the AMOC during these events led to significant cooling in Europe and the North Atlantic, as well as failures in the Indian and Asian monsoons.
These findings have implications for future climate scenarios, as current models suggest the AMOC may weaken under global warming conditions.
While the AMOC has remained stable for the past 11,700 years, there are concerns about its future behavior. Buizert warns, “We know the AMOC will weaken, but will it collapse? That is the big question”.
This study points to the non-linear nature of climate change and the potential for abrupt, irreversible shifts.
As we face the challenges of global warming, understanding these ancient climate events becomes increasingly crucial for predicting and preparing for future climate scenarios.