Hi,

Very interesting, I had not heard of that angle before. But I do not
believe it yet.

anthropogenic warming over the last 8000 years

The second graph of his Figure 1 shows a "natural CO2 trend" vs. an
observed CO2 trend. What "natural trend"? The data points left of
8000 years are just as observed as those right of that mark. So the
data plotted assumes an interpretation and that _always_ makes me
very sceptic.

Let's assume there is some sort of natural cause for a gradual drop
in CO2 concentration. What could have happened 8000 years ago that
caused a sharp turn in the trend?

massive deforestation of Eurasia irrigation for rice farming in
Southeast Asia, and increases from biomass burning, livestock
production

First of all I question the impact of these reasons on atmospheric
CO2 concentration. Methane? OK, cows fart. But how does even todays
livestock compare to the natural animal population. Or do cows fart
more than Gnus.

And I question the magnitude of the effect.

At the very least there should be a slow upturn in the trend as human
population slowly rises and the human factors overlay the "natural
trend". And not a sharp bend at -8000 years and a linear increase since
then. I mean 8000 years! What kind of population are we talking?

Attributing that graph to human activity does not make sense to me, this
looks like some natural source of extra CO2 that has been opened 8000
years or a sink that has been plugged. And that does not make much sense
either.

We only really started burning fossil fuels 150 or so years ago. And there
is no doubt that that does raise atmospheric CO2 concentration. Shouldn't
there be another upturn in the trend near the right end of the graph? Or
is the absolute value of that change so small that it would not show up?

In other words, by burning all those trees and fossil fuels we may
have accidentally saved ourselves from a far worse fate than global
warming.

That may be the case. It even may be true that we have been working to
achieve that effect for much longer that the last two centuries.

But that does not mean we can stop here and relax!

There is no doubt that we are still raising the levels of greenhouse gasses
at an ever acelerating rate. Even if we were lucky by changing the climate
in the past what do we do now?

So the theory presented in the article is interesting but of no real help
for the future.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de
"Ich hoffe Sie können mir helfen. Ein Freund hat mir einen tollen
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