Natural global warming

[JohnB]

I generally agree with your argument but your argument does not result in a conclusion that net CO2 effect must necessarily be significant and positive.

While the CO2 effect must be positive (and possibly significant) as you say the net effect is another matter. I'm rapidly coming to the opinion that since the feedbacks for warming don't really rely on what causes the warming (eg. The oceans will outgas CO2 as they get warmer regardless of whether the warming is caused by an increase in CO2 or Solar radiation) it becomes pointless to concern yourself with one particular forcing.

 

The system is so complex and the feedbacks are so interconnected and inter-reliant that the system can only be considered as a whole.

 

I look forward to your comments on the other thread.

Edited December 12, 2010 by JohnB

[steevey]

Again, I will ask you for a citation.

 

 

on page 29 of the Smithsonian Earth book, The editor-in chief is James F. Luhr.

 

 

[swansont]

OK, I found some online resources on snowball earth. They indicate that the source of the cooling is a reduction in greenhouse gases; whether or not CO2 started higher than the current levels has to be considered in conjunction with the fact that solar luminosity was ~4% lower than it currently is, and that CH4 was much higher then than it is now.

 

http://www.snowballearth.org/cause.html

http://www.giss.nasa.gov/research/briefs/sohl_01/

[steevey]

OK, I found some online resources on snowball earth. They indicate that the source of the cooling is a reduction in greenhouse gases; whether or not CO2 started higher than the current levels has to be considered in conjunction with the fact that solar luminosity was ~4% lower than it currently is, and that CH4 was much higher then than it is now.

 

http://www.snowballe....org/cause.html

http://www.giss.nasa...briefs/sohl_01/

 

According to the book, there was more greenhouse gases, and the evidence for that comes from carbonated sediments dating back to that time period. Is there maybe a particular snowball Earth where greenhouse gases were lower? Or maybe in the very last one, green-house gases began to fall?

But, while I was searching on the internet for something, I found this

 

http://earth.geology...feng%20EPSL.pdf

 

It would explain more in-depth how the continents got to be so focused near the equator and how that impacted the Earth.

Edited December 12, 2010 by steevey

[swansont]

According to the book, there was more greenhouse gases, and the evidence for that comes from carbonated sediments dating back to that time period. Is there maybe a particular snowball Earth where greenhouse gases were lower? Or maybe in the very last one, green-house gases began to fall?

But, while I was searching on the internet for something, I found this

 

http://earth.geology...feng%20EPSL.pdf

 

It would explain more in-depth how the continents got to be so focused near the equator and how that impacted the Earth.

 

As I stated, the CO2 levels could have been higher then, but one must also consider that the methane levels were also higher, and the solar output was smaller. One cannot simply compare CO2 levels then to the current levels and draw a valid conclusion about steady-state temperatures.

[steevey]

As I stated, the CO2 levels could have been higher then, but one must also consider that the methane levels were also higher, and the solar output was smaller. One cannot simply compare CO2 levels then to the current levels and draw a valid conclusion about steady-state temperatures.

 

True, but you also have to consider the fact that even though greenhouse gas was more prevalent, the Earth was still frozen. With the ice-caps extending to the equator, almost all of the sun's light was reflected. So clearly, there are other factors causing global warming today.

Edited December 12, 2010 by steevey

[swansont]

True, but you also have to consider the fact that even though greenhouse gas was more prevalent, the Earth was still frozen. With the ice-caps extending to the equator, almost all of the sun's light was reflected. So clearly, there are other factors causing global warming today.

 

Nobody disputes this.

[steevey]

Nobody disputes this.

 

 

Good