Global Warming: A closer look at the numbers

What fraction of the impact on global warming is due to gases released by human activity? That's the question addressed by: Global Warming: A closer look at the numbers

And the winning number is:

Adding up all anthropogenic greenhouse sources, the total human contribution to the greenhouse effect is around 0.28% (factoring in water vapor).

The take-away for readers:

Known causes of global climate change, like cyclical eccentricities in Earth's rotation and orbit, as well as variations in the sun's energy output, are the primary causes of climate cycles measured over the last half million years. However, secondary greenhouse effects stemming from changes in the ability of a warming atmosphere to support greater concentrations of gases like water vapor and carbon dioxide also appear to play a significant role. As demonstrated in the data above, of all Earth's greenhouse gases, water vapor is by far the dominant player.

The ability of humans to influence greenhouse water vapor is negligible. As such, individuals and groups whose agenda it is to require that human beings are the cause of global warming must discount or ignore the effects of water vapor to preserve their arguments, citing numbers similar to those in Table 4b . If political correctness and staying out of trouble aren't high priorities for you, go ahead and ask them how water vapor was handled in their models or statistics. Chances are, it wasn't!