smeggy wrote:
gopher wrote:
Edited for accuracy, we must remember that we only produce a small part of CO2 compared with nature. (3% IIRC)
You're right to highlight the AGW factor.
Do you have a source for the 3% figure? If true it should be quite damning.
A brief search reveals.....
Quote:
About 95 percent of the greenhouse effect — the atmospheric warming due to the trapping of solar energy that makes life possible on Earth — is due to water vapor, 99.999 percent of which is of natural origin.
The other 5 percent of the greenhouse effect is due to carbon dioxide, methane, nitrous oxide and other miscellaneous gases.
Although carbon dioxide is the most dominant of these gases by volume, comprising about 99.4 percent, the other gases trap more heat. So the contribution of carbon dioxide to the 5 percent of the greenhouse effect not due to water vapor is much less than 99.4 percent — it's about 72 percent.
Carbon dioxide, therefore, is responsible for roughly 3.6 percent of the greenhouse effect (5 percent, representing the percentage of the greenhouse effect not due to water vapor, multiplied by 72 percent, representing the percentage of that 5 percent due to carbon dioxide).
But carbon dioxide is produced both naturally and by humans. About 97 percent of atmospheric carbon dioxide is natural, in fact. Only about 3 percent is from human activity.
That means that only about 0.11 percent of the greenhouse effect (that is, 3 percent of 3.6 percent) is due to human releases of carbon dioxide into the atmosphere.
Put another way, about 99.89 percent of the greenhouse effect has nothing to do with carbon-dioxide emissions from human activity.
From here:
http://www.foxnews.com/story/0,2933,123013,00.htmlWhich links to the source here:
http://www.junkscience.com/Quote:
Q. What percentage of the CO2 in the atmosphere has been produced by human beings through the burning of fossil fuels?
A. Anthropogenic CO2 comes from fossil fuel combustion, changes in land use (e.g., forest clearing), and cement manufacture. Houghton and Hackler have estimated land-use changes from 1850-2000, so it is convenient to use 1850 as our starting point for the following discussion. Atmospheric CO2 concentrations had not changed appreciably over the preceding 850 years (IPCC; The Scientific Basis) so it may be safely assumed that they would not have changed appreciably in the 150 years from 1850 to 2000 in the absence of human intervention.
In the following calculations, we will express atmospheric concentrations of CO2 in units of parts per million by volume (ppmv). Each ppmv represents 2.13 X1015 grams, or 2.13 petagrams of carbon (PgC) in the atmosphere. According to Houghton and Hackler, land-use changes from 1850-2000 resulted in a net transfer of 154 PgC to the atmosphere. During that same period, 282 PgC were released by combustion of fossil fuels, and 5.5 additional PgC were released to the atmosphere from cement manufacture. This adds up to 154 + 282 + 5.5 = 441.5 PgC, of which 282/444.1 = 64% is due to fossil-fuel combustion.
Atmospheric CO2 concentrations rose from 288 ppmv in 1850 to 369.5 ppmv in 2000, for an increase of 81.5 ppmv, or 174 PgC. In other words, about 40% (174/441.5) of the additional carbon has remained in the atmosphere, while the remaining 60% has been transferred to the oceans and terrestrial biosphere.
The 369.5 ppmv of carbon in the atmosphere, in the form of CO2, translates into 787 PgC, of which 174 PgC has been added since 1850. From the second paragraph above, we see that 64% of that 174 PgC, or 111 PgC, can be attributed to fossil-fuel combustion. This represents about 14% (111/787) of the carbon in the atmosphere in the form of CO2.
From here:
http://cdiac.esd.ornl.gov/pns/faq.html - Carbon Dioxide Information Analysis Center
Mike.
_________________
www.misspelled-signs.com - A tribute to illiterate signwriters.