Just how much of the "Greenhouse Effect" is caused by human activity?
It is about 0.28%, if water vapor is taken into account-- about 5.53%, if not.
This point is so crucial to the debate over global warming that how water vapor is or isn't factored into an analysis of Earth's greenhouse gases makes the difference between describing a significant human contribution to the greenhouse effect, or a negligible one.
Synopsis
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).
For all the figures please check out the article at http://www.geocraft.com/WVFossils/greenhouse_data.html it's not very long and it's well worth the read to put things in perspective.
About the author:
" There is no dispute at all about the fact that even if punctiliously observed, (the Kyoto Protocol) would have an imperceptible effect on future temperatures - one-twentieth of a degree by 2050. "
Dr. S. Fred Singer, atmospheric physicist
Professor Emeritus of Environmental Sciences at the University of Virginia,
and former director of the US Weather Satellite Service
Comments
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!