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Author Topic: The PETM occurred close to an 'eccentricity maximum' in Earth's orbit of the Sun  (Read 1219 times)

kassy

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Hellish Warming Event in Earth's Ancient Past Triggered by Rare Orbital Quirk in Space

...

he PETM, like other extreme heating episodes in Earth's ancient past, is considered an analogue for the anthropogenic climate change we see unfolding in the world today.

But while Earth's current predicament can be attributed squarely to human activity, the mysterious origins of the PETM's heatwave have never been totally understood. What triggered it?

In a new study, scientists say they have an answer: Earth's orbital eccentricity in a Solar System defined by chaos.

According to oceanographer Richard Zeebe from the University of Hawaii at Manoa and geoscientist Lucas Lourens from Utrecht University in the Netherlands, the PETM occurred close to an 'eccentricity maximum' in Earth's orbit of the Sun.

In other words: a point where, during an epic 405,000-year astronomical cycle, Earth most clearly deviated from a perfect circle in orbiting the Sun, inviting world-changing consequences if the eccentricity exposed Earth to more solar radiation.

and more cool stuff on:
https://www.sciencealert.com/hellish-warming-event-in-earth-s-ancient-past-triggered-by-rare-orbital-quirk-in-space

So we finally know what triggered the PETM. Pretty cool.  8)
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gerontocrat

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Hellish Warming Event in Earth's Ancient Past Triggered by Rare Orbital Quirk in Space

In a new study, scientists say they have an answer: Earth's orbital eccentricity in a Solar System defined by chaos.

According to oceanographer Richard Zeebe from the University of Hawaii at Manoa and geoscientist Lucas Lourens from Utrecht University in the Netherlands, the PETM occurred close to an 'eccentricity maximum' in Earth's orbit of the Sun.

In other words: a point where, during an epic 405,000-year astronomical cycle, Earth most clearly deviated from a perfect circle in orbiting the Sun, inviting world-changing consequences if the eccentricity exposed Earth to more solar radiation.
Poor old Newton.

His clockwork solar system upended by Chaos Theory. Mind you, clockwork still works for our lifetimes, and the way things are going, probably for the lifetime of Homo Sapiens. (Extinction or idiocracy?)
"Para a Causa do Povo a Luta Continua!"
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Tom_Mazanec

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Here is how bad the Eocene was:
A new model of the Earth's climate 50 million years ago is revealing worrisome clues about what our future could look like
https://www.insider.com/model-of-eocene-warming-could-improve-predictions-about-climate-change-2019-9
Quote
That model's calculations turned out to match up with what scientists already knew based on geological evidence: that the Earth had warm temperatures globally during the Eocene, with only a small difference in temperatures between the poles and the equator. The epoch began with a temperature rise of 5 to 9 degrees Celsius.

Before the Eocene even started, global sea levels were estimated to be 40 to 100 meters higher than they are currently. Then sea levels rose even more for millions of years due to a lack of ice on the poles. In the Arctic Circle, there were crocodiles, palm trees, and sand tiger sharks.

and
A WORLD OF SEARING HEAT AND MELTED ICE CAPS: CLIMATE MODEL OF EARLY EOCENE IS 'SCARY FINDING' FOR EARTH'S FUTURE
https://www.newsweek.com/co2-climate-change-early-eocene-scary-1459956
Quote
"We were surprised that the climate sensitivity increased as much as it did with increasing carbon dioxide levels," Jiang Zhu, an environmental research fellow at the University of Michigan, said in a statement. "It is a scary finding because it indicates that the temperature response to an increase in carbon dioxide in the future might be larger than the response to the same increase in CO2 now. This is not good news for us."
« Last Edit: September 20, 2019, 11:56:12 PM by Tom_Mazanec »
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

oren

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"Earth most clearly deviated from a perfect circle in orbiting the Sun" = reached maximum eccentricity, in everyday terms. The article writer did not say that at other times Earth does orbit in a perfect circle.

kassy

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Some more work relating the 405k cycle:

Scientists show solar system processes control the carbon cycle throughout Earth's history

...

Using chemical data from ancient mudstone deposits in Wales, an international team involving scientists from Trinity College Dublin discovered that periodic changes in the shape of Earth's orbit around the Sun were partly responsible for changes in the carbon-cycle and global climate during and in between the Triassic-Jurassic Mass Extinction (around 201 million years ago, when around 80% of the species on Earth disappeared forever) and the Toarcian Oceanic Anoxic Event (around 183 million years ago).

...

"Our work shows that for the 18 million years or so in between the Triassic-Jurassic mass extinction and the Toarcian Oceanic Anoxic Event, Earth's global carbon-cycle was in a constant state of change."

"Periodic changes in the shape of Earth's orbit around the sun impacted on the amount of energy received by Earth from the sun, which in turn impacted climatic and environmental processes, as well as the carbon-cycle, on local, regional and global scales."

"Although this phenomenon is well known for having caused the glacial cycles in more recent times, the present study shows that these external forcing mechanisms on Earth's systems were also operating, and controlling Earth's carbon cycle in the distant past, even during non-glacial times when Earth was marked by hot-house climate conditions."

https://www.sciencedaily.com/releases/2020/02/200210153341.htm

*

Orbital pacing and secular evolution of the Early Jurassic carbon cycle

Cyclic variations in Earth’s orbit drive periodic changes in the ocean–atmosphere system at a time scale of tens to hundreds of thousands of years. The Mochras δ13CTOC record illustrates the continued impact of long-eccentricity (405-ky) orbital forcing on the carbon cycle over at least ∼18 My of Early Jurassic time and emphasizes orbital forcing as a driving mechanism behind medium-amplitude δ13C fluctuations superimposed on larger-scale trends that are driven by other variables such as tectonically determined paleogeography and eruption of large igneous provinces. The dataset provides a framework for distinguishing between internal Earth processes and solar-system dynamics as the driving mechanism for Early Jurassic δ13C fluctuations and provides an astronomical time scale for the Sinemurian Stage.

https://www.pnas.org/content/early/2020/02/04/1912094117


And this article is about the same cycle but just putting the link here so i can find it later.

The articles introduction is a nice introduction to the cycles with a whole bunch of links to research.

https://www.sciencedirect.com/science/article/pii/S1674987119301197
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.