Throughout the last ice age, the climate changed repeatedly and rapidly where Greenland temperatures rose between 5 and 16 degrees Celsius in decades. The climate system changed like a series of dominos falling in succession. This is the result of a study by a group of researchers from the University of Copenhagen.
Understanding abrupt climate changes in the past is crucial to our ability to predict whether something similar will occur now or in the near future.
Many studies have tried to determine which part of the climate system changed first when these approximately 30 abrupt climate changes, called Dansgaard-Oeschger events, began. Could it have been, for example, the ocean currents in the North Atlantic, the wind and rainfall patterns in the Northern Hemisphere, or the spread of sea ice in the Arctic that triggered the climate change.
The team used data from two Greenland ice cores that spanned the last ice age to determine in what order the parts of the climate system changed at the beginning of the abrupt climate transitions.
The analysis showed that changes in different paths of the climate system-ocean currents, sea ice and wind patterns-likely triggered and reinforced each other. One of the climate dominos that could have disrupted the entire system during the last ice age was the extent of sea-ice cover in the North Atlantic. This is worrisome because the modern extent of sea ice has been declining at a significant rate since the 1980s, highlighting the risk of a similar domino effect due to man-made climate change.
https://phys.org/news/2021-04-abrupt-ice-age-climate-cascading.html