Climate Change: How Abrupt Climate Shifts Impacted Earth After the Ice Age
How did an abrupt climate shift impact Earth? New research has taken a closer look as to how climatic changes in the North Atlantic propagated globally.
The history of climate on Earth is stored in tiny variations in kilometer-thick ice cores, sediments from lakes and oceans, and other natural archives that are layered down over thousands of years and works as archives of past temperatures. By recovering and deciphering these archives, researchers can reveal how and white the climate changed in the past, and in this way learn how the climate system may react in the future as the planet warms and the ice sheets melt.
As the Earth warmed out of the last ice age, the climate of the northern hemisphere high-latitudes became extremely unstable. Ice cores from the Greenland Ice Sheet document temperature jumps of 10 degrees Celsius in the space of just a few decades. In order to understand how climate can change so rapidly and whether similar events could be lurking in the future is a major part of climate research.
By comparing the climate records with climate model results, researchers were able to confirm previous ideas that increasing northward heat transport in the Atlantic warms the North Atlantic and Greenland at the expense of the abrupt cooling in the South Atlantic-a concept known as the bipolar ocean seesaw.
The researchers found that atmospheric circulation adjusts in an effort to compensate for the change in ocean heat transport. As the ocean transports more heat northward, the atmosphere responds by transporting more heat southward. However, the compensation is imperfect.
"Our research underlines the intimate coupling between the ocean and atmosphere and helps to explain why past abrupt climate change unfolded so differently in different regions on Earth," said Joel Pedro, one of the researchers, in a news release. "The study further underlines a warning that climate scientists have been issuing for many years: forcing the climate system into a different state, as occurred during the warming out of the last ice age, can trigger climate instability with impacts that spread globally."
The findings are published in the journal Nature Geoscience.
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