As species of plants and animals died, amoebas with small forests continued to be called, which continued to form strong shells from calcium and other deep-sea minerals, as if they had hundreds of millions of years. When each forum essentially died – transformed into sediment of the ocean – they kept a small piece of Earth’s ancient history alive in their fossil shells.
For decades, scientists have studied shells that look for clues about the temperature of the Earth’s ancient ocean, its carbon budget, and the composition of minerals circulating through the air and the sea.
Now, in a new study published today (10 September) in the journal Science, Researchers have analyzed chemical elements in thousands of forum samples to create Earth’s most detailed climate record – and find out how serious our current climate situation is.
The new paper, which includes several decades of deep-sea drilling missions in a single record, details Earth’s climate swings throughout the Cenozoic era – a 66 million-year period that began with the death of dinosaurs and the current era. Extends human induced climate change.
Results show how Earth transitioned through four different climate states – dubbed warmhouse, hothouse, coolhouse, and icehouse states – responses to changes in planetary orbit, greenhouse gas levels, and polar ice sheet extent In.
The zig-zagging chart (shown above) ends with a daring peak. According to the researchers, the current pace of anthropogenic global warming is higher than the natural climate fluctuations seen at any other point in the Cenozoic era, and hyper-drives our planet into a submerged state exiting a prolonged iceberg state. Has the ability to do.
“Now that we have succeeded in capturing natural climate variability, we can see that the predicted anthropological warming will be much higher than that,” studies co-author James Zachos, professor of earth and planetary science at the University of California, Santa Cruz. , Said in a statement.
“Intergovernmental Panel on Climate Change (IPCC) estimates a ‘business-as-a-normal’ scenario for 2300 would potentially bring global temperatures to a level the planet has not seen in 50 million years.” (The IPCC is a United Nations group that assesses the science, risks and impacts of climate change on the planet.)
In the hothouse
To compile their new era-long climate map, the study authors examined fossil-like shells – long tubes of rock, sediment, and microbes – in deep sea sediment cores – drilled from the world’s oceans over the past several decades Has gone.
Vanams (short for Foraminifera) are microscopic plankton whose oldest relatives appeared in the ocean a billion years ago; Deep scientists dig into the seabed, the old famed specimens they uncover.
Forum shells contain important climate information in the ratio of carbon and oxygen isotopes (the elements versions). The ratio between oxygen isotopes oxygen-18 and oxygen-16, for example, may reveal how hot the surrounding water was when the Asar formed its shell; High ratio, cold water.
The ratio between carbon-13 and carbon-12 indicates how much organic carbon was available for the microbes to eat; Here, a higher proportion correlates with more greenhouse gases (such as carbon dioxide) in the atmosphere.
Because the team’s climate record covers such an incredibly long period of time, the researchers also had to consider the astronomical effects on the planet’s climate – that is, the Earth’s slowly changing orbit and tilt toward the sun, the sunlight. It affects the quantity when it reaches different parts of the planet. At different times, also known as the Milankovitch cycle.
When the team acquired the orbital data along with its isotopic climate data, they observed that the orbital variations caused different but relatively small-scale changes in the global climate. Researchers said that critically, each major jump between climate states was associated with large-scale changes in greenhouse gas levels.
For example, about 10 million years after the extinction of dinosaurs, Earth leaped from a warmhouse state to a hothouse state. The phenomenon, known as the Paleocene – Eocene thermal maximum, is 16 degrees Celsius above modern levels, Zakos said, and was driven by a huge flow of carbon in the vast atmosphere, Zakos said. Which was the result of volcanic eruptions. North Atlantic.
Similarly, carbon dioxide disappeared from the atmosphere over the next 20 million years, ice sheets began to form in Antarctica and the planet entered a coldhouse phase, with surface temperatures about 4 degrees above modern levels.
About 3 million years ago, Earth entered a snowhouse phase in the Northern Hemisphere powered by waxing and weaning ice sheets. Now, human greenhouse gas emissions are increasing temperatures, which cannot be seen in tens of millions of years.
This increase goes beyond the natural variations triggered by the Earth’s changing orbit, the researchers concluded. And if current greenhouse emissions remain constant, the climate may skyrocket back to later levels of the Paleocene – Eocene thermal maximum. The transition from icehouse to hothouse would not take millions of years, Zachos said – it would take hundreds.
“We now know more accurately whether it was hot or cold on the planet and have a better understanding of the underlying dynamics and processes driving them,” lead study author Thomas Westerold, director of the University of Bremen Center for Marine Environmental Sciences in Germany Said in the statement.
“Time since 66 [million] 34 million years ago, when the planet was much warmer than it is today, is particularly interested, as it represents a parallel in the past to what anthropogenic changes may occur in the future. ”
Originally published on Live Science.