Climate scientists probe Earth’s ice to better understand a warming planet

As the summer of 2024 is on track to become the hottest on record, scientists are digging deep into the Earth’s coldest corners to recover an icy record of what the atmosphere was like hundreds of thousands of years ago. 
“It’s amazing that we have this ability to see back into time and see that the Earth’s environment, including the climate, has changed radically and in many different ways,” said University of California, Berkeley professor Kurt Cuffey.
The researchers are using a powerful tool called ice coring. Cuffey, an ice core paleoclimatologist, told CBS News Bay Area how his field is a major achievement of modern science. 
The technique, used by the oil industry to drill wells, is now being used to study our ancient atmosphere and climate. Researchers drill into glaciers and ice sheets to retrieve vertical cylinders of ice created from hundreds of centuries of snowfall. Each layer is a frozen time capsule, telling the story of what the Earth was like when that layer of snow fell.
“You get layers of ice that get older and older and older as you go down,” said Cuffey.
This reporter learned firsthand about ice coring when studying abroad in Greenland. Almost 80% of the island is covered by an ice sheet and it’s where researchers from around the world arrive to retrieve ice cores, to gain new knowledge on ice stream dynamics and our past climate.  
The project is called the East Greenland Ice-core Project or “EastGRIP” for short. I recently spoke about it with physicist and paleoclimatologist Sune Olander Rasmussen from the prestigious Niels Bohr Institute in Copenhagen, Denmark, renowned for its ice-core research.
He raised his hands into a circle in front of him, showing us a diameter of about five to six inches.
“From this cylinder, which is about this big, we can retrieve all kinds of information about past climate,” said Rasmussen.
One example of data that can be recovered is stored in the trapped air bubbles found in the layers. These are little pockets of atmosphere that are frozen as the snow turns into hardened ice. 
“So, in compressing snow to ice, we capture tiny, tiny, tiny samples of the past atmosphere,” said Rasmussen. 
In these trapped bits of ancient air, scientists can measure levels of greenhouse gases, such as carbon dioxide and methane, and compare the data to current levels.
In the cores, scientists can also reconstruct the history of past air temperatures and see traces of volcanic events.
“There are many volcanic layers but most of them are not visible, “said Rasmussen.
By understanding the science, the physics, and the cold hard facts of how and why climate changed in the past, scientists hope to better predict what may occur in the future.
“I’m a lot more confident that the climate forecasts are accurate because of the work that we’ve done looking at these past events,” said Cuffey.
Earth has experienced many ice ages that are broken up by periods of warmer temperatures, called an interglacial, where carbon dioxide levels are higher.
The planet is currently in a warm period. But the scientists believe this time is different.
“We’re pushing the climate system into a realm where it hasn’t gone by itself in a lifetime,” said Rasmussen.
“What’s really unprecedented is not what has happened up to date to the year 2024, it’s what will happen inevitably if we keep burning fossil fuel,” added Cuffey.
The data from Ice cores is just one piece of the puzzle of understanding our climate system. More details can be collected from tree rings, sediment cores retrieved from ocean and lake beds, as well as fossils.