Alternate Ice Age

[Jdailey1991]

Back home, the Pleistocene ice ages were as follows:

Start Date
2.5 million years ago

Orbital Eccentricity
Between 0.000055 and 0.0679, with the mean of 0.0019

Axial Tilt
Between 22.1 and 24.5 degrees in a duration of 41,000 years

Axial Precession
26,000 years




In this alternate scenario, the Pleistocene ice ages of Great Lakes Earth were as follows:

Start Date
5 million years ago

Axial Tilt
Between 20 and 25 degrees in a duration of 61,500 years

Axial Precession
46,800 years

With these differences, would the climate, landscape and overall geologic timeline be drastically different or not quite different compared to our Pleistocene?

 

[Geo]

I know you posted this quite some time ago, but since reconstructing climate is my area of expertise I will give it a try.

Because your axial tilt is larger than that of our Earth, you must expect larger precesional-related insolation changes (meaning larger differences in the energy receive from the sun depending of the precesional cycle), and also a higher contrast between southern and northern hemispheres, which may not be of much interest to you if you are looking at the entire Earth but just a small portion of territory on the northern hemisphere.

Of course, the sum of the different frequencies may also alter the duration and extension of each of the cooling cycles (e.g., the seesaw patter observed in the sedimentary records of Earth would not be the same than that of your world).

The timeline would be --for sure-- altered. Exactly how, is difficult to say. Because you've changed the frequency in each of the parameters, the resulting cycle (cooling/warming) could have the same or very similar frequency but very distinctive amplitudes, and the modulation of the amplitude must be on a very different frequency.

It would be easier to give you a straight answer if only one of the cycles timing was different.

I hope this is helpful.