Carbon dioxide at its highest level in 3 million years: Study

The study found that Ice Age onset, and the start of the glacial cycles from cold to warm and back, was mainly triggered by a decrease of Carbon dioxide levels.

The levels of the greenhouse gas carbon dioxide (CO2) in the atmosphere are higher today than ever before in the past three million years, according to a study.

The onset of the Ice Age and the start of the glacial cycles from cold to warm and back, were triggered by a decrease in the Carbon dioxide levels. (iStock/Representative Image)

For the first time, scientists from the Potsdam Institute for Climate Impact Research in Germany succeeded to do a computer simulation that fits ocean floor sediment data of climate evolution over this period of time.The study found that Ice Age onset, and the start of the glacial cycles from cold to warm and back, was mainly triggered by a decrease of CO2-levels.

Today, it is the increase of greenhouse gases due to the burning of fossil fuels that is fundamentally changing our planet, according to the study published in the journal Science Advances.

Global mean temperatures never exceeded the preindustrial levels by more than 2 degrees Celsius in the past three million years, the study shows.

The current climate policy inaction, if continued, would exceed the 2° limit already in the next 50 years, researchers said.

“We know from the analysis of sediments on the bottom of our seas about past ocean temperatures and ice volumes, but so far the role of CO2 changes in shaping the glacial cycles has not been fully understood,” said Matteo Willeit of the Potsdam Institute for Climate Impact Research, lead author.

“It is a breakthrough that we can now show in computer simulations that changes in CO2 levels were a main driver of the ice ages, together with variations of how the Earth’s orbits around the sun, the so-called Milankovitch cycles,” he said.