Posted on 10/30/2019 3:10:35 PM PDT by BenLurkin
During the past 2.6 million years, Earth’s climate has alternated between warm periods known as interglacials, when conditions were similar to those of today, and cold glacials, when ice sheets spread across North America and northern Europe. Before about 1 million years ago, the warm periods recurred every 40,000 years, but after that, the return period lengthened to an average of about 100,000 years. It has often been suggested that a decline in the atmospheric concentration of carbon dioxide was responsible for this fundamental change. Writing in Nature, Yan et al.1 report the first direct measurements of atmospheric CO2 concentrations from more than 1 million years ago. Their data show that, although CO2 levels during glacials stayed well above the lows that occurred during the deep glacials of the past 800,000 years, the maximum CO2 concentrations during interglacials did not decline. The explanation for the change must therefore lie elsewhere.
Understanding what caused the shift in periodicity, known as the mid-Pleistocene transition (MPT), is one of the great challenges of palaeoclimate science. The 40,000-year periodicity that dominated until about 1 million years ago is easily explained, because the tilt of Earth’s spin axis relative to its orbit around the Sun varies between 22.1° and 24.5° with the same period. In other words, before the MPT, low tilts led to cooler summers that promoted the growth and preservation of ice sheets.
But after the MPT, glacial cycles lasted for two to three tilt cycles. Because the pattern of variation in Earth’s orbit and tilt remained unchanged, this implies that the energy needed to lose ice sheets2 had increased. One prominent explanation3 is that atmospheric levels of CO2 were declining, and eventually crossed a threshold value below which the net cooling effect of the decline allowed ice sheets to persist and grow...
(Excerpt) Read more at nature.com ...
ping
It's called the Sun.
Beats me. Why would glacial periods suddenly triple what can be explained by the tilt cycles? Aliens? I don’t know.
It sounds like CO2 is not the boogeyman.
All their projects have been wrong and none of their trends are happening.
Other articles have appeared in the last year saying, 'any warming might not be as bad as we projected.'
In the next couple of years we're going to see a lot of new theories explaining why the old theories didn't pan out.
“In the next couple of years we’re going to see a lot of new theories explaining why the old theories didn’t pan out.”
Let me guess. Capitalism and Christianity. Yeah, that’s it.
For all their instruments and measurements and PhDs these clowns don’t have a clue. Yet we are bombarded with authoritarian statements claiming all sorts of dire consequences if we don’t give total power to technologists amd their cohorts, the bureaucrats.
It’s the second biggest scam of the Century, just behind the shrinks and their DSM bogus BS.
Or swapping orbits with Mars, when we were on intersecting orbits.
One can realize what a worthless crock of psychobabble that whole dissertation is if one remembers that Earth itself is only between 6,000 and 10,000 years old.
It would be a bummer if we reduced CO2, and then discovered that we were overdue for our next glacial period, and the CO2 levels had been the only thing holding it off...
That is exactly what is happening.
So it was a 40,000 year cycle till 1M years ago when the cycles got longer.
Either the Sun changed it’s behavior or the Earth’s orientation changed very slightly.
I’m going to hypothesize (that’s scientific for guessing based on an idea) since it was so abrupt that the Earth got it’s noggin’ popped by a fairly large something or other just enough to change the cycle.
Earth got it’s noggin’ popped by a fairly large something or other just enough to change the cycle.
Could’ve been a couple of ‘somethings’ - plus the angle and location would not necessarily require it to be as big as something hitting closer to the equator.
The only know somethings that hit the Earth and caused massive climate change were comet debris 12800 years ago which incinerated all life on the North American continent bringing on the Younger Dryas Age - the coldest period in ‘recent history’. Prior to that, nothing other than the Sun’s output striking Earth caused climate change.
That we are aware of....
Whoops, will ping this later (two lists).
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