[cogitator]

Prior global temperature rises were higher than the current one, are periodic, and appeared long before human activity.

Certainly, but the key area of the plot you posted is the area subsequent to the last glacial period termination. Even though the resolution of this graph is coarse for that time period, it should be discernible that temperatures have been fairly stable. In fact, since the last glacial period the temperatures for this interglacial have been abnormally stable for the Pleistocene interglacials. That's why human activities, which have forced the CO2 concentration in the atmosphere about 80 ppm higher than the natural peak values seen in the data (the red line in the plot) are adding a perturbation to a stable climate period. Increasing CO2 in the atmosphere alters Earth's radiative balance such that a global temperature increase would be the likeliest outcome.

[Ditto]

Increasing CO2 in the atmosphere alters Earth's radiative balance such that a global temperature increase would be the likeliest outcome.

As I read the chart, CO2 tracks temperature. There is a very pronounced lag between periods of increased temp., and increased CO2 which would say global warming increases CO2, not the other way around.

[Paloma_55]

Increasing CO2 in the atmosphere alters Earth's radiative balance such that a global temperature increase would be the likeliest outcome.

I think you should preface this argument with the html tags... [Speculation] and [/Speculation] Yes, CO2 is subtantially higher in the atmosphere and very likely due to human activity. However, you have no data that the "stable climate period" we are seeing is not due to that CO2. How does C02 affect climate dynamics?? This is pure speculation. For all you know, it could ultimately lead to a stabilization of temperatures. C02 levels typically lag global temperature, so we can conclude that they are not causal, and if anything, *may* be the cause of the downturn in temperatures we see when global C02 levels get close to 300ppm.

[slowhandluke]

Increasing CO2 in the atmosphere alters Earth's radiative balance such that a global temperature increase would be the likeliest outcome.

From the graphs earlier, it is more likely is that the human activity is promoting an un-precedented period of stable temperatures, keeping us from the extreme decline usually seen when the world gets this warm.

CO2 follows warming in these charts, so it isn't a cause. You can't even show that the CO2 rise is due to some burning or oxidation process, or simply a release of C02 trapped in the ocean as the water warms.

[Old Professer]

Except that, in the past, the temps were 4-6 degrees higher with an ice core reading for CO2 of 280ppm; why is that?

[UCANSEE2]

"Increasing CO2 in the atmosphere alters Earth's radiative balance such that a global temperature increase would be the likeliest outcome."

Which could alter the ph level of the ocean, Which could affect sea life.
Which could affect the amount of cloud cover. Which could affect the temperature. Which could affect how fast plants grow. Which could affect how much CO2 they take in and how much Oxygen they give off. Which could......