From this well-structured (if not slightly dry) web site:
- This is the statistically correct way to represent relative human contributions to the greenhouse effect:
- 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).
