xTYBALTx

The fact that global warming is a theory is not derisive, is my point. So it wouldn't make sense to call it a theory as a way of making it less believable.


In order to understand what increased levels of CO2 mean to us, as humans, why don't we just take a look at the earth when it had higher levels of CO2? Additionally, the graph is intended to challange the 'Al Gore graph' which purports to show a relationship between CO2 concentrations and global temperature.

The graph suggests the existence of highly elevated (by today's standards) levels of CO2 in the atmosphere for a sustained period ranging from ~40 - 140 million years ago. During this time, CO2 levels range from two to seven times their current levels. This time frame encompasses a geological period known as the Cretaceous period, which is famous for the massive abundance and variety of flora and fauna - including mammals.

The climate was much warmer than today's, by as much as 9-12C. That is 9-12C warmer, but with as much as seven times modern CO2 concentrations. All of the industrial activity in the past one hundred years has - at most - increased CO2 concentrations from 300ppm to 360ppm. The Cretaceous period, which remember was absolutely teeming with life and was only 9-12C warmer, is estimated to have had CO2 concentrations as high as 2000ppm - for sustained periods lasting for tens of millions of years.

Keep in mind, however, that I am granting a causal and direct relationship between CO2 levels and global temperature. As we all know, there is no reason to believe in the existence of this causal relationship. Perhaps temeperature drives CO2 levels. Perhaps the relationship between temperature and CO2 levels is far more complex than that. There could even be no relationship at all - we simply don't know.

Oh, and finally, whether the earth's atmosphere has changed a lot or a little throughout the Phanerozoic, which began ~565 million years ago and continues through today, is all a matter of perspective.

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Current good song: Justice - Stress

eGoatBoy

Not to be an a$$, but for focus (as much for my benefit as anyone else's):

This is awesome! It took me awhile to stop laughing...I had heard before that methane produced by livestock was a major contributor. I bet the people who wrote the report were vegetarians ( just kidding).

Seriously though, it's a good point that offsets the focus on man-made CO2, however serves to highlight that there may in fact be problem, and a man-made one at that (do I have to give up my SUV and my tasty Ribeye steak )


I hear ya on this...but as difficult as these discussions are it's better that they happen, than not. IMHO


Thanks for the clear explanation. This is awesome stuff!

I think your comments suggest that [1] there is a rising level of man-made CO2 in the atmosphere, but that [2] it may not be all that bad.

Coming back to the causal relationship of CO2 and global temperature though...I think the green-house effect is well understood to drive temperatures up (look at Earth, look at Venus). The green-house effect is driven by certain gasses, e.g. CO2 (aka my SUV) and methane (aka my Ribeye steak). There seems to be a solid link there...can that link be called causal??

IF more green-house gasses THEN higher temperature.

What am I missing...why is the causal link in doubt?

Cheers,

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Boot

The formula is fine: If A then B. The problem is which to assign to A and etc. That is a very large "well understood" you posit, when in fact we do not know if we the Earth is warmer from CO2, or if we have more CO2 because the Earth is warmer.

It has been documented above that the man-made percentages of CO2 are miniscule compared to those naturally occuring, so it's quite believeable that the increase in CO2 is due to something as simple as warmer water absorbing less of it.

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Boot.

In Soviet Russia, TV watches YOU.

xTYBALTx

Or, for that matter, it's possible that there is no relationship between CO2 and global temperature whatsoever.

Perhaps earth's temperature variations result from the sun's varying radiation output, cloud cycles, urban heat islands, or god knows what else. The impetus is on the global warming folks to prove anthropogenic global warming and the greenhouse effect. And the evidence just isn't there. If you want to convince us, then show us the evidence.

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Current good song: Justice - Stress