Before 1965, low CO2 levels were stable for 2.5 million years

According to a new study, humans have never lived in the highly charged atmospheric CO2 conditions of the last 60 years.

As Yige Zhang, a professor at Texas A & M University's College of Geosciences, explains, carbon dioxide is a greenhouse gas that contributes to warming the earth's atmosphere. Since the warming of the Earth's atmosphere is a problem, much of the planet is focused on carbon dioxide (CO2) – and rightly so. It keeps going up, up.

Scientists use ice cores to determine ancient climate data and reveal many of them. See Exhibit A below.

"This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, shows that atmospheric CO2 has increased since the industrial revolution," says NASA.

But as Zhang explains, ice cores only cover the last 800,000 years. What to do? Start by examining the soil, as did Zhang and his colleagues, especially the soil carbonates from the Loess Plateau in central China.

"The Loess Plateau is an incredible place to watch Eolian, or the wind, the accumulation of dust and dirt," Zhang said. "The first dusts identified on this shelf date from 22 million years ago, so the recordings are extremely long.The loess and palaeosol layers contain soil carbonates that record atmospheric carbon dioxide. if we have very attentive eyes. "

Using the techniques described in their paper, "Low CO2 Levels of the Pleistocene Era as a Whole," the researchers constructed a history of Pleistocene carbon dioxide, dating from 2.6 million to 11,700 years ago.

"According to this study, of the first Homo erectus, which currently dates from 2.1 to 1.8 million years ago, until 1965, we live in a low carbon dioxide environment," Zhang said.

During the 2.5 million years of the Pleistocene, CO2 concentrations averaged 230 parts per million.

In 1965, CO2 concentrations exceeded 320 parts per million for the first time in 2.5 million years. Current levels are over 410 parts per million.

The numbers correlate with the results of the ice core analysis, "suggesting" that the Earth's system has operated under low levels of CO2 throughout the Pleistocene, "said Dr. Junfeng Ji of Nanjing University.

"It is important to study the atmospheric concentrations of CO2 in the geologic past, because we know that there are already climatic consequences and that there will be more climatic consequences, and it will not be possible. One of the ways to know these consequences is to examine the history of the Earth, "he said. "Then we can see what kind of CO2 level we had, what the climate looked like and what the relationship was between them."

It is difficult to imagine the impact of this dramatic change in atmospheric conditions. "We have evolved in a low-carbon environment," Zhang said, and we do not know how we will evolve and be affected by modern levels of CO2.

"This current environment rich in carbon dioxide is not just an experience for the climate and the environment – it's also an experience for us, for ourselves," Zhang said.

The study was published in Nature Communications.