Conditions During Last Ice Age Could Hold Clues For Future Climate

A recent study by a group of researchers at Australian National University (ANU) demonstrated a new way of recreating ocean conditions in the Atlantic during the Last Glacial Maximum (LGM) which occurred around 20,000 years ago.

What is the Last Glacier Maximum (LGM)?
The Last Glacial Maximum (LGM) was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Vast ice sheets covered much of North America, Northern Europe, and Asia and profoundly affected Earth’s climate by causing drought, desertification, and a large drop in sea levels.

The study gave us a much clearer understanding of the conditions during the last ice age. This could even lead to better models for future climate predictions.

Lead author Dr. Jimin Yu says scientists have been trying to reconstruct ocean circulation for this time period for decades, because of the clues it offers about past CO₂ levels and changes in climate. “The LGM was a time of much lower CO₂ levels, lower global temperature, and lower sea levels,” he added.

With so much research going on, there is new data on LGM coming out and old ocean models couldn’t explain it. That’s why there was a need for change in thinking, the researchers said.

The research team from ANU used marine sediments to reconstruct deep-water carbonate ion which traces reflecting seawater acidity, using it the team generated a unique map showing water conditions for the last glacial Atlantic.

This map reveals a new glacial deep Atlantic circulation model.

The researchers found that the carbon-rich pacific deepwater extended 20 degrees south in the south Atlantic at 3-4 kilometers depth during the LGM. This might have contributed to the decline in carbon dioxide helping the initiation of LGM according to Dr. Yu

Oceans and ocean circulation is very important for climate regulation as it stores and transports heat, carbon dioxide and nutrients. And with this new information we can test performance of various climate models and try to predict future climate with more accuracy.

“If a model is able to reproduce the data—a method known as hindcasting or backtesting—it might give us confidence in the model’s ability to map out future climate conditions,” Dr. Yu said.

The research has been published in Nature Geoscience