Compared to the concentration statistics in Table 1, the GWP comparison in Table 2 illustrates, among other things:
Total carbon dioxide (CO2) contributions are reduced to 72.37% of all greenhouse gases (368,400 / 509,056)-- (ignoring water vapor).
Also, from Table 2 (but not shown on graph):
Anthropogenic (man-made) CO2 contributions drop to (11,880 / 509,056) or 2.33% of total of all greenhouse gases, (ignoring water vapor).
Total combined anthropogenic greenhouse gases becomes (28,162 / 509,056) or 5.53% of all greenhouse gas contributions, (ignoring water vapor).
As illustrated in this chart of the data in Table 3, the combined greenhouse contributions of CO2, methane, N2O and misc. gases are small compared to water vapor!
Total atmospheric carbon dioxide (CO2) -- both man-made and natural-- is only about 3.62% of the overall greenhouse effect-- a big difference from the 72.37% figure in Table 2, which ignored water!
Water vapor, the most significant greenhouse gas, comes from natural sources and is responsible for roughly 95% of the greenhouse effect (5). Among climatologists this is common knowledge but among special interests, certain governmental groups, and news reporters this fact is under-emphasized or just ignored altogether.
Conceding that it might be "a little misleading" to leave water vapor out, they nonetheless defend the practice by stating that it is "customary" to do so!
When greenhouse contributions are listed by source, the relative overwhelming component of the natural greenhouse effect, is readily apparent.
From Table 4a, both natural and man-made greenhouse contributions are illustrated in this chart, in gray and green, respectively. For clarity only the man-made (anthropogenic) contributions are labeled on the chart.
Water vapor, responsible for 95% of Earth's greenhouse effect, is 99.999% natural (some argue, 100%). Even if we wanted to we can do nothing to change this.
Anthropogenic (man-made) CO2 contributions cause only about 0.117% of Earth's greenhouse effect, (factoring in water vapor). This is insignificant!
Adding up all anthropogenic greenhouse sources, the total human contribution to the greenhouse effect is around 0.28% (factoring in water vapor).