After reading your link, decided to Google “images of earth temperature charts for past million years.” Unfortunately, only a few of these charts cover one million years. A lot only go to 400K or 800K or many millions of years. The second link shows one specific chart and it’s site which does cover 800K. [I wish I knew how to transfer over these graphics to FR comments.] Interestingly, there is a strong drop right were one would expect with your linked article. Also interesting is the unusually low drop in atmospheric CO2 (orange line). My question: What is it that causes the periodic drops approximately every 100K years? It looks like we might be due for one soon (10K year+-).
There’s been a lot of time and cash expended on trying to find periodicity and repeating phenom. in the paleontological record, in proxy climate data, that kind of thing. I don’t think of it as a productive use of resources, insofar as there *is* no pattern to (for instance) big impacts.
The objects themselves have random masses, and various origins, which means, over time, their orbits will evolve differently. Every once in a while one crosses paths with the Earth, and if the mass is right, Earth gives it the old come-hither, and *boom*. Same goes for other large bodies, which are more likely to bump into something, just because they’re a tad wider target.
CO2 levels in the Antarctic ice cores (for instance) show that the CO2 levels *rise* a century or more *after* the warming, meaning that the increase in temperature permits more biological activity of all kinds, and voila.
> A geomagnetic reversal is a change in a planet’s magnetic field such that the positions of magnetic north and magnetic south are interchanged. The Earth’s field has alternated between periods of normal polarity, in which the direction of the field was the same as the present direction, and reverse polarity, in which the field was the opposite. These periods are called chrons. The time spans of chrons are randomly distributed with most being between 0.1 and 1 million years[citation needed] with an average of 450,000 years. Most reversals are estimated to take between 1,000 and 10,000 years. The latest one, the Brunhes-Matuyama reversal, occurred 780,000 years ago; and may have happened very quickly, within a human lifetime.[1] A brief complete reversal, known as the Laschamp event, occurred only 41,000 years ago during the last glacial period. That reversal lasted only about 440 years with the actual change of polarity lasting around 250 years. During this change the strength of the magnetic field dropped to 5% of its present strength.[2] Brief disruptions that do not result in reversal are called geomagnetic excursions.
https://en.wikipedia.org/wiki/Geomagnetic_reversal