No Evidence That Global Warming is manmade, page 5

Originally posted by Muaddib
And I also note with interest that you are giving a link to Real Climate, a website where Michael Mann is one of the directors...the same Mann that tried to make a dissapearing act of the Medieval Warming and the Little Ice Age events....

A more balanced view…

Originally posted by Muaddib

Maudibb
How about that source for your graph???

That graph itself gives credit to it's creators.

www.geocraft.com is not very helpful, but I managed to figure it out. Moreover, the graph itself improperly credits the sources for the information. You have to go here to see that.

The two sources are:

Temperature after C.R. Scotese

and

CO2 after R.A. Berner & Z. Kothavala, 2001 .

So let’s discuss this graph.

First, as I have already pointed out, it is a compilation of data from two graphs into one.

The creator seems to make a lot of undocumented claims, found nowhere in the underlying sources:

For example, Berner’s actual research paper says:

This means that there appears to have been very high early Paleozoic levels of CO2, followed by a large drop during the Devonian, and a rise to moderately high values during the Mesozoic, followed by a gradual decline through both the later Mesozoic and Cenozoic. This type of modeling is incapable of delimiting shorter term CO2 fluctuations (Paleocene-Eocene boundary, late Ordovician glaciation) because of the nature of the input data which is added to the model as 10 my or longer averages.

Did you get that???? 10 Million year increments!

He continues:

Thus, exact values of CO2, as shown by the standard curve, should not be taken literally and are always susceptible to modification. Nevertheless, the overall trend remains. This means that over the long term there is indeed a correlation between CO2 and paleotemperature, as manifested by the atmospheric greenhouse effect.

But wait! Isn’t that the opposite of what our West Virginia guy says?

Berner is also quoted here saying:

“The geologic record over the past 550 million years indicates a good correlation,” said Robert A. Berner, a Yale geologist and pioneer of paleoclimate analysis. “There are other factors at work here. But in general, global warming is due to CO2. It was in the past and is now.”

Apparently, the co-author of Berner’s paper, Z. Kothavala, even says:

It is now well known that concentrations of greenhouse gases in the atmosphere have been increasing since the mid 19th century as a result of human activities.

www3.interscience.wiley.com...=1&SRETRY=0" target="_blank" class="postlink" rel="nofollow"> "Assessing simulations of daily temperature and precipitation variability with global climate models for present and enhanced greenhouse climates", by K. McGuffie, A. Henderson-Sellers, N. Holbrook, Z. Kothavala, O. Balachova, and J. Hoekkstra, International Journal of Climatology, vol. 19, pg. 1-2 (1999)

Also found www.drudgeforum.com..." target="_blank" class="postlink" rel="nofollow">here.

With regard to Scotese’s portion of the graph…

Unlike Berner and Kothavala, who actually studied the issue of CO2 and temperature correlation, Scotese never says anything of the kind. Why? Because his focus is on plate tectonics…NOT the GW issue.

This graph is a bad PASTE job with no science to support the assertions being made from it.

[edit on 3-4-2007 by loam]