The white vastness of the Antarctic territory may seem empty, but it hides valuable records of Earth’s past. Scientists at the University of Colorado at Boulder have been using cylinders of ice—also called cores or cores—to unravel changes in the chemical composition of the atmosphere and Earth’s temperature.
In January of this year, the team of researchers presented a study that brings data from up to 11,000 years ago, demonstrating the connections between seasonal temperature cycles in Antarctica and variations in the intensity of solar radiation. “This is the first record of its kind,” says Tyler Jones, who led the study.
Through the observed amount of isotopes — variants of the same chemical element but with different numbers of neutrons in their atomic nuclei — experts are able to infer average temperatures in the past: the hotter, the heavier isotopes of hydrogen are more frequent.
The research linked the temperature increases in the Antarctic summer with the Milankovitch Cycles: variations in the Earth’s orbit that favor the arrival of solar radiation. The study validated this connection, responsible for long-term climate changes, different from the current ones, caused by human activities.
Deciphering the information that ice holds is no easy task. Periods with little snow can leave the cores with data gaps, as they result in layers that are too thin to analyze. The measurements made by the scientists were made every 5 millimeters of the extracted ice cylinder, which would represent a few weeks of snow falling.
Understanding the natural variations of climate on Earth is important to identify precisely what is not natural. Jones hopes that his study with ice cores can contribute and encourage similar ones. “We can learn a lot by focusing on seasonal weather in the future,” he says, “provided records can be obtained.”
