Ice is older than civilization
The Antarctic Ice Sheet covers about 98% of the area of Antarctica and is the largest accumulation of ice on Earth. Its area is 14 million km2, and its volume is 26.5 million km3 of ice. The Antarctic Ice Sheet contains about 61% of all fresh water on Earth, which is equivalent to 58 m of sea level. The average thickness of the East Antarctic ice is 2.5 km, and the maximum is almost 4.8 km.
Ice drilling. Photo: Anna Malyaeva
The new core was extracted as part of the European Antarctic Ice Research project. In the ancient layers, air bubbles have been preserved — a kind of time capsules containing samples of the atmosphere of the past. The analysis showed that the concentration of carbon dioxide clearly followed the changes in global temperature over many climatic cycles.
An international group of scientists has presented the longest continuous archive of the planet’s climatic history. The researchers extracted ice cores with a total length of 2.8 kilometers from the depths of Antarctica and restored data on the Earth’s climate over the past 1.2 million years. The work may help scientists understand why the ancient ice ages were not equally harsh.
The oldest ice layers are over a million years old. For comparison, the first representatives of intelligent people appeared only about 300 thousand years ago. The Antarctic core stores data on periods when completely different climatic conditions existed on Earth.
The researchers hope that the new ice archive will make it possible to find out what role carbon dioxide, oceans and fluctuations in the Earth’s orbit played in these changes.
The air of the past refines computer models
Modern climate models often rely on indirect data about the ancient climate. However, the air bubbles in the Antarctic ice contain real samples of the atmosphere of the past. Thanks to this, scientists can directly measure the concentration of carbon dioxide, methane and other gases.
It is believed that greenhouse gases previously played an insignificant role compared to what happened after, but the reason for the change has not been precisely established. That’s why we needed a record from which we could extract both the gas concentration and temperature. And so we got it.
Such studies are especially important against the background of the current increase in greenhouse gas emissions. According to climatologists, the current level of co₂ in the atmosphere is already significantly higher than in most periods of the last hundreds of thousands of years.
A “time machine” has been found in the Antarctic ice: the core has revealed how the climate and atmospheric composition have changed over a million years. The previous record of the antiquity of the continuous ice archive was about 800 thousand years. The new core extended the Earth’s climatic “memory” by one and a half times.
Dmitry Pavlov
