A warming planet, without CO2 increase?

[zankaon]

Might one have a warming planet, without CO2 increase? The last 15,000 years is evidence for such case, since pre-industrial CO2 is considered as ~280. If one had a slow down in vertical mixing (i.e. lower surface water turnover; say 1% over 100 yrs for 15,000 yrs- giving 150%), resulting gradually in persistent surface warming; then might this surface 'greenhouse' effect (assuming all other parameters constant), result in increased photosynthesis, and hence an increasing carbon sink - reinforcing a lower atmospheric CO2? Hence perhaps warming of atmosphere from upper layer of ocean, while maintaining a lower atmospheric CO2? Would such scenario (model) seem applicable to Holocene warming? Might the Paleocene/Eocene warming have also had a lower CO2; rather than the assumption that a warm planetary period must have a high CO2, or of other greenhouse gases such as methane? http://en.wikipedia.org/wiki/Eocene"

 

[Skyhunter]

If ocean overturning slowed it would result in cooler ocean temperatures since more heat would remain at the surface where it is more readily lost to the atmosphere.

 

[Xnn]

Highly accurate temperature measurements of the ocean have been made for the last 50 years.
These are measurements that extend to great depths (using buoys and other devices).
From these measurements, it has become clear that the oceans are warming.
So, heat has been flowing from the atmosphere into the oceans; not the other way around.

 

[zankaon]

Might one have a warming planet, without CO2 increase? The last 15,000 years is evidence for such case, since pre-industrial CO2 is considered as ~280. If one had a slow down in vertical mixing (i.e. lower surface water turnover; say 1% over 100 yrs for 15,000 yrs- giving 150%), resulting gradually in persistent surface warming; then might this surface 'greenhouse' effect (assuming all other parameters constant), result in increased photosynthesis, and hence an increasing carbon sink - reinforcing a lower atmospheric CO2? Hence perhaps warming of atmosphere from upper layer of ocean, while maintaining a lower atmospheric CO2? Would such scenario (model) seem applicable to Holocene warming? Might the Paleocene/Eocene warming have also had a lower CO2; rather than the assumption that a warm planetary period must have a high CO2, or of other greenhouse gases such as methane? http://en.wikipedia.org/wiki/Eocene"

Might averaged thermocline be statistically shifted for over successive 100 yr bins? For ex., W. Pacific for near Indonesia, ~ 140 ft., and in E. Pacific, ~ 40 ft. for non El Nino effect. Might we be under-estimating nature's delayed response to new carbon sources? That is, can nature compensate with expansion of carbon sinks? For ex., greenhouse effect of warming planet leading to increased photosynthesis? Might CO2 realizations plateau out, courtesy of nature's expanded carbon sinks?

 

[Xnn]

The largest carbon sink is the ocean.
The polar oceans are currently absorbing CO2 while the tropical oceans are offgassing.
Problem is that as the polar oceans warm, they will stop aborbing CO2.
Measurements of the Carbon cycle have already shown that the amount of CO2 absorbed is a function of temperature. Warmer temps result in less absorption.

This is one of the reasons why projected warming from CO2 is so dire.
That is warming and CO2 increases are linked.

See Chapter 7 for a summary of the current understanding regarding the carbon cycle.
In particular, 7.3.3 Terrestrial Carbon Cycle Processes and Feedbacks to Climate

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter7.pdf