Seventy million years ago, then Large asteroids Approximately hit the earth with explosive energy rays 1 billion atomic bombs, The sky was covered with ash, dust and steam rock cover and slowly rain fell on the earth. As species of plants and animals died en masseForms, called small under amoebas, continued to reproduce, forming a stronger shell from calcium and other deep sea minerals, as they had been for millions of years. When every forum inevitably died – plunged into the silt of the seabed – they kept a small part of the ancient history of the earth alive in their fossilized shells.
For decades, scientists have studied those shells, finding clues about the ancient Earth’s ocean temperature, its carbon budget, and the composition of minerals in the air and oceans. Now, in a new study published today (Sept. 10) in the journal Science, Researchers have analyzed chemical elements in thousands of forum samples to create the most detailed climate record on Earth so far – and it shows just how dire our current weather conditions are.
The new paper, which covers decades of deep ocean drilling missions in a single record, details the Earth’s climate circulating throughout the region. Cenozoic era – million 66 million years period began with the death of Jenny Dinosaurs And extends to the human-inspired current era Climate change. The results show how the Earth transitioned into four different climate states – known as wormhouses, hothouses, coolhouses and icehouse states, in response to changes in the planet’s orbit. Greenhouse gas Level and extent of polar ice sheets.
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The zig-zagging chart (shown above) ends with a final peak. The current pace of anthropology, according to researchers global warming The natural environment fluctuations seen at any other stage in the Cenozoic era are exceeded, and our planet is likely to be hyper-driven from the long ice-cold phase to the serene hothouse state.
“We have now succeeded in capturing the variability of the natural environment, so we can see that the projected anthropogenic,” said James Zachos, co-author of the study, and James Zachos, co-author of the study. Will be much more than that. ” , Said in a statement. Intergovernmental Panel on Climate Change (IPCC) Estimates for 2300 The ‘business-as-usual’ scenario would bring global temperatures to a level that the planet has not seen in 500 million years. “(The IPCC is a United Nations group that assesses the science, risks and effects of climate change. Planet.)
Inside the hothouse
To compile their new epoch-long climate map, study authors examined fossil forum shells of ores deep sea sediment cells – long tubes of silt, silt and microbes drilled from the world’s oceans over the past few decades. The foramen (short for foraminifera) are microscopic plankton whose earliest relatives appeared in the ocean a billion years ago; Scientists dig in the seashore, they uncover the samples of the forum.
The ratio of no Carbon And Oxygen Isotopes (versions of elements) in forum shells contain severe climatic information. Oxygen isotopes The ratio between oxygen-18 and oxygen-16, for example, can reveal how hot the surrounding water was when the foramen formed its shell; The higher the amount, the colder the water. The ratio between carbon-13 and carbon-12 shows how much organic carbon was available for microbes to eat; Here, a higher ratio atmosphere is more compatible with greenhouse gases (such as carbon dioxide).
Because the team’s climate record covers such an extremely long period of time, the researchers also had to consider the astronomical effects on the planet’s atmosphere – how the Earth’s slowly changing orbit and inclination toward the Sun affect the amount of sunlight reaching different parts of the Earth. At different times, also known as Milankovich cycle. When the team compared orbital data with their isotopic climate data, they found that orbital variations make specific but relatively small changes in the global environment. Critically, every major leap between climate states was tied to mass Greenhouse gas Level, the researchers said.
For example, about 10 million years after the dinosaurs became extinct, Earth The warmhouse went from a state to a hothouse state. The phenomenon, known as the Paleocene-Eocene thermal maximum, saw temperatures of 29 degrees Fahrenheit (16 degrees Celsius) above modern levels, Zecos said, and large amounts of carbon were released into the atmosphere, which was thought to be the result. A huge volcano erupted in the North Atlantic. Similarly, over the next 20 million years, carbon dioxide disappeared from the atmosphere, and ice sheets began to form. Antarctica And the planet entered a coolhouse phase, with a surface temperature averaging 7 F (4 C) above average.
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About a million million years ago, the Earth entered an icehouse phase, moving through the northern hemisphere by waxing and melting ice sheets. Now, temperatures are rising to an extent due to human greenhouse gas emissions, which have not been seen for millions of years. The increase is outside the natural variation caused by the Earth’s changing orbit, the researchers concluded. And if current greenhouse emissions remain stable, the climate could return to paleocene-Eocene thermal maximum levels not seen since. The transition from icehouse to hothouse will not take millions of years, Zaccos said – it will take hundreds.
“We now know more accurately when it was hot or cold on the planet and have a better understanding of the underlying dynamics and the processes that drive them,” said Thomas Westerhold, lead study author at the University of Bremen’s Center for Marine Environmental Sciences. Germany, the statement said. “From time 66 [million] Millions of 34 million years ago today, when the planet was significantly warmer than it is, it is particularly interesting, as it represents a parallel to the past, which could lead to a change in anthropology in the future. “
Editor’s note: The story was updated on September 11 to correct the two Celsius and Fahrenheit conversion.
Published on Original Living Science.
