]]>
a little bit of chemistry: most oil-based fuels have at least 7 carbon atoms in each molecule and most of the rest of the molecule is hydrogen... the smallest atom. Carbon Dioxide (CO2) has one carbon atom and 2 slightly bigger oxygen atoms. If we compare molecules, one gasoline molecule (mostly heptane - 7 carbons), when completely burned, produces 7 molecules of CO2 which all weigh a bit more then 3 times as much as the carbon alone. That hydrogen has no neutrons in it's nucleus so it's molecular weight is about 1 and carbon is about 12 and heptane would have 7 x 2 + 2 = 16 hydrogen atoms. For simplicity that is about the same as 8 carbons for heptane making about 7 x 3 = 21 carbons-worth of CO2. Oxygen is about 15 for molecular weight so we can correct that as (15+15+12)/(12 x 3) x 21 = 24.5 or an expansion factor of about 24.5/8.2 = 3.
world crude oil consumption for 2010 is a bit more then 87,000 thousand barrels (). Assuming a gradual steady increase since 1925 to 2010 (see graph below), the triangle formed is half the area so an estimate is going to be 87,000 x (2010-1925) / 2 = about 3 700 000 thousand barrels. A barrel of Texas crude is 138.8 kg. One range I found was 125.600 154.695 (depending on type) so lets use 140 kg. I will use tonnes instead of tons (a ton is about 9/10 of a tonne) which are 1000 kg. This then gives us 3 700 000 000 x 140 x 3 / 1000 = 1 554 000 000 tonnes of CO2. This is of course only crude oil and does not include natural gas (1 carbon atom and 4 hydrogen so also expands about a factor of (15 + 15 + 12)/(12 + 4)= 2.625) and propane (42 x 3 / ((3 x 2 +2)+(3 x 12))=2.864) which account for more carbon then crude by far.
edit: I am not done... we need to know how many cubic kilometers of CO2 that is for the comparison. The density of CO2 at sea level (STP = Standard Temperature and Pressure) is 1.9769 g/L and on average, it will be half that (as we move toward outer space). A liter is a cubic decimeter and 10 000 decimeters is a kilometer so there are 10 000^3 = 1 000 000 000 000 liters in a cubic kilometer and 1000 000 g in a tonne. This makes the calculation to be 1 554 000 000 x 1 000 000 x 2 / 1.9769 / 1 000 000 000 000 = 1 572 cubic kilometers. That still seems small.
edit 2: haha... that consumption number was PER DAY! That makes my totals to be 574 173 cubic kilometers (and about 567 000 000 000 tonnes)
edit 3: a more careful estimation of total use using that graph could be:
130 x (1970-1925) / 2 + 70 x (2012-1970) + (130-70) x (1980-1970) /2 = 6 165 000 000 "bbls" (compared to my first estimate of 3 700 000 000). This makes for a correction factor of 5/3 (1.66621) so we now get 956 700 cubic kilometers of CO2.
Statistics: Posted by Ann Vole — Wed Apr 11, 2012 10:25 am
]]>
]]>
]]>
]]>
]]>
]]>
]]>
]]>
]]>