Human influence on atmospheric CO2

This will be an evaluation of how much CO2 humans put into the atmosphere, showing how easily obtainable facts and a little math can dispel a lot of superstition. I strongly urge you to go through the calculations yourself.

How much CO2 is in the atmosphere?
as of the year 1800, about 280 ppm (parts per million), as of 2000, about 370 ppm http://earthguide.ucsd.edu/globalchange/keeling_curve/01.html
How much is that? Here we can take advantage of a couple of neat tricks. First, as we know from barometric pressure, the atmosphere over our heads weighs as much as a column of water 10 meters deep, so the atmosphere weighs the same as a layer of water 10 meters deep covering the earth. Second, the kilometer was originally defined as 1/10,000 of the distance from the equator to the pole, so figuring earth's area uses simple numbers that are easy to remember. Finally, a cubic meter of water weighs a metric tonne. Do the math and you find that the atmosphere weighs 5.03*10e15 tonnes. Times 370 parts per million means there were 1.87*10e12 tonnes of CO2 in the atmosphere as of the year 2000.
Since fossil fuels are mostly carbon, this amount is usually expressed by its carbon content. With carbon having an atomic weight of 12 and oxygen 16, the carbon content of CO2 is 12/44 of this total or 510 billion tonnes of carbon in the atmosphere as CO2.
how much are we putting in?
I always go to the CIA factbook first for geopolitical and economic data
http://odci.gov/cia/publications/factbook/index.html
gives oil and natural gas production , at 75 million barrels/day and 2.6 trillion cubic meters/year
http://www.eppo.go.th/ref/UNIT-OIL.html gives conversions, so oil is 3750 million tonnes/year, and natural gas is 2300 million tonnes/year. Natural gas (CH4) is 3/4 carbon, while oil is about 11/13, so the carbon content is 3190 and 1750 respectively for a total of 4940 million tons of carbon a year from oil and natural gas.
http://www.eia.doe.gov/emeu/aer/txt/ptb1114.html gives coal at 5227 million short tons/year or about 4700 tonnes. Using an average carbon content of 50% this is 2350 million tonnes
Total carbon usage, then, is just over 7.300 billion tonnes per year as of 2001.
According to these back-of-the-envelope calculations, we're putting out CO2 equal to about 1.4% of the atmospheric total every year, and this has increased the total in the atmosphere by a little over 1/3 since the industrial revolution.