Carbon Footprint

[MarillionFan]

For many people a substantial reduction in greenhouse gas emissions can be achieved by driving a more fuel-efficient vehicle. Each gallon of gasoline burned produces 10kg (20 pounds) of carbon dioxide [US Department of Energy]. A motorist driving 15,000 miles a year in a vehicle that delivers 30mpg will produce 5000kg of carbon emissions whereas a vehicle returning 50mpg will produce 3000kg.

Right.

I have a bee in my bonnet about this. I read in the Times yesterday that burning a Gallon of Petrol produces 10KG of Carbon Dioxide.

Now a Gallon of petrol weights 8lbs or approx (3.6KG).

On the basis of my limited understanding, how come an 8lb Gallon produces a 22lb output of Carbon Dioxide. Yeh, I know theres a reaction with Oxygen etc etc but I reckon this is absolute bollocks.

Where's the proof. This carbon footprint stuff is bollocks.

[Gonzo]

C'mon.

Someone must have paid more attention during chemistry than I did.

Now the question for me is why should I feel guilty about my carbon footprint when I take a flight? It's not as though I charter them - I get on ones that are going anyway so I therefore make no individual contribution

[EqualOpportunities]

For many people a substantial reduction in greenhouse gas emissions can be achieved by driving a more fuel-efficient vehicle. Each gallon of gasoline burned produces 10kg (20 pounds) of carbon dioxide [US Department of Energy]. A motorist driving 15,000 miles a year in a vehicle that delivers 30mpg will produce 5000kg of carbon emissions whereas a vehicle returning 50mpg will produce 3000kg.

Right.

I have a bee in my bonnet about this. I read in the Times yesterday that burning a Gallon of Petrol produces 10KG of Carbon Dioxide.

Now a Gallon of petrol weights 8lbs or approx (3.6KG).

On the basis of my limited understanding, how come an 8lb Gallon produces a 22lb output of Carbon Dioxide. Yeh, I know theres a reaction with Oxygen etc etc but I reckon this is absolute bollocks.

Where's the proof. This carbon footprint stuff is bollocks.

It's worse than that... That lot have a small gallon; it's only 4/5 the size of ours.

[_V_]

It seems impossible that a gallon of gasoline, which weighs about 6.3 pounds, could produce 20 pounds of carbon dioxide (CO2) when burned. However, most of the weight of the CO2 doesn't come from the gasoline itself, but the oxygen in the air.

When gasoline burns, the carbon and hydrogen separate. The hydrogen combines with oxygen to form water (H2O), and carbon combines with oxygen to form carbon dioxide (CO2).

A carbon atom has a weight of 12, and each oxygen atom has a weight of 16, giving each single molecule of CO2 an atomic weight of 44 (12 from carbon and 32 from oxygen).

Therefore, to calculate the amount of CO2 produced from a gallon of gasoline, the weight of the carbon in the gasoline is multiplied by 44/12 or 3.7.

Since gasoline is about 87% carbon and 13% hydrogen by weight, the carbon in a gallon of gasoline weighs 5.5 pounds (6.3 lbs. x .87).

We can then multiply the weight of the carbon (5.5 pounds) by 3.7, which equals 20 pounds of CO2!

[EternalOptimist]

one pound of fuel requires about 15 pounds of air in the combustion engine. Only one fifth of the air is oxgen so the total weight out of the exhaust for a pound of fuel is 4 pounds.
for a gallon of fuel this is 24 pounds out of the exhaust, two parts water vapour, one part carbon dioxide (plus a few traces such as unused fuel, carbon monoxide and nitrous oxide)

How these proportions are reflected by weight I defer to V, but the ball park looks about right.

As a matter of interest, water vapour is a much more potent green house gas than CO2 and the combustion process produces twice as much, it never gets a mention? why ?

Because nature produces much more than we do and doesnt pay taxes or breast beat.

[andy]

I blame fat people ,they have the largest foot print or people with large foot size

[freakydancer]

I blame fat people ,they have the largest foot print or people with large foot size

fatties definitely have the deepest footprints

[Sockpuppet]

No. I have massive feet and a small todger.

[OwlHoot]

fatties definitely have the deepest footprints

But they also act as carbon reservoirs - If all 6 billion people in the world, not counting the relatively few who are already obese, packed an extra half hundredweight of blubber that would be 150 million tons, of which a significant proportion would be carbon. Snag is, they'd need to use a lot more fuel hauling their fat arses round in various forms of transport. So maybe there would be no net benefit.

Come to think of it though, why not breed genetically engineered ants or worms and suchlike prone to putting on weight? I'm sure their total biomass must far outstrip that of humans, and no one could complain it was cruel to put a strain on their little hearts because insects and worms don't have them.

[VectraMan]

But they also act as carbon reservoirs - If all 6 billion people in the world, not counting the relatively few who are already obese, packed an extra half hundredweight of blubber that would be 150 million tons, of which a significant proportion would be carbon. Snag is, they'd need to use a lot more fuel hauling their fat arses round in various forms of transport. So maybe there would be no net benefit.

Yes but fat people would die earlier, which would reduce the overall consumption of resources.