(a) temperature changes occur first and lead to CO2 emission from natural sources (e.g., more ocean outgassing upon warming, more CO2 retention as the ocean cools), indicating that warmer temperatures are driving up CO2 concentrations significantly more than human activity or fossil fuels;
(b) CO2 only accounts for a small portion of the greenhouse effect relative to water vapor/cloud; and
(c) our presumptions about paleoclimate CO2 concentrations are probably inaccurate (too low and too stable), as significant temperature fluctuations would have caused wider fluctuations in CO2 concentrations than current proxy-based reconstructions indicate.
Together, emission from ocean and land sources (∼150 GtC/yr) is two orders of magnitude greater than CO2 emission from combustion of fossil fuel. These natural sources are offset by natural sinks, of comparable strength. However, because they are so much stronger, even a minor imbalance between natural sources and sinks can overshadow the anthropogenic component of CO2 emission.”
And page 249:
The vast majority of that [greenhouse] warming is contributed by water vapor. Together with cloud, it accounts for 98% of the greenhouse effect.” pg. 249
Surface temperature depends on the atmosphere’s optical depth. The latter, in turn, depends on atmospheric composition through radiatively active species. Water vapor is produced at ocean surfaces through evaporation. Carbon dioxide is produced by decomposition of of organic matter. These and other processes that control radiatively active species are temperature dependent.”
– See more at: http://notrickszone.com/2016/05/13/salby-sees-little-co2-driving-mechanism-skeptical-view-of-co2-science-is-in-fact-textbook-science/#sthash.Ttx9i6Uw.dpuf