Re: Guide for anti-AATers

Phillip Bigelow (
1 Nov 1995 14:15:23 -0800 (H. M. Hubey) writes:

>I'm looking at p. 177 of CEHE. The oxygen isotope ratio (O18/O16) is
>pointing towards 5.0 at the top of the chart (which is the present
>time) and it falls as we go back. Since less O18 is precipitated
>at high temperatures (relative to O16) that means is was hotter
>before. Unfortunately it's not possible to get a more accurate
>reading from the graph.

I have seen that graph in CEHE, and granted, it is horrendous as a source of
good paleo-temp. data. And keep in mind that the Pliocene oceanic
temperature range was as variable as it is in the Holocene. None-the-less,
depending on WHAT body of water you want your imaginary "aquatic ape" to
frollic in, you are going to have do your homework. Since you are convinced
that 95-and-up water temps were extensive enough for an aquatic ape
environment, then YOU provide US with the scientific journal reference(s)
that say this type of water temp. was found in East Africa during the
Pliocene. A generalized graph (that doesn't even deal with East African
coastlines, by the way) just isn't going to cut it. It isn't rigorous
enough (even by your own admission; see your comment above).

>But so far it looks like it is now
>the coldest for the past 60 million years since the ratio is
>the highest now in the past 60 million years.

You are wrong. Oxygen isotope ratios indicate a much colder average
global oceanic water temperature during the glacial stades (which occurred,
intermittantly, from 2.0 m.y.a. to 11,000 years ago. My advice to
you is to seek out a better source for paleo water temperatures.
From my own work on Miocene paleo-environments, I have read journal
publications that strongly suggest that a polar ice build-up started as
early as the late Miocene. Depending on where you are in the world during the
Miocene, you could very easily find yourself in climates that are at least
as cool as the Holocene, and in a few places you would even be cooler. My
admonishment to you to USE DATA ONLY FROM PLIOCENE EAST AFRICA still stands.