There is a large difference between knowing something and feeling something. Knowledge is
powerful but if it is not connected to intuition and emotion it does not lead to action. Think of
this dynamic as our head vs. our gut. This disconnect is at play as people think about Green
House Gas (GHG) where we are told that we each person is responsible for many tons of GHG
per year. The science of climate change that has demonstrated beyond doubt that increases in
GHG lead to planetary increases in temperature with catastrophic effect. Why is this so difficult
to act on?
One reason for this failure to act is that most people don’t think of gas (Green House Gas or any
other gas) as weighing anything. Gas is air -and air is apparently weightless. So, there is an
intellectual understanding that we produce tons of GHG – without an accompanying feeling or
intuition that makes it real to us.
A second disconnect is that the act of burning something apparently makes it lighter – not
heavier. A cord of wood that weighs 2,000 pounds may be reduced to 200 pounds of ashes.
Anyone who has ever put a log in a fireplace and then cleaned out the ashes knows the ashes
are much lighter than the log.
Intellectually we know that gas has a mass and that combustion is actually combining a material
with oxygen – and since we are combining- not subtracting- the mass has to go up. Our head
knows this – but how can we feel it?
Here are two exercises to help connect the head to the gut.
Gas has weight. These two real life examples help our “gut” believe that gas has weight. Most
of us have seen propane gas tanks used for gas grills. When empty the tare (weight when
empty) is 17 pounds – but when the tank is full the weight is 37 pounds – which is to say that
the gas is 20 pounds. An even simpler mental experiment is to think of a tea kettles weight
when full of water. Boiling the water away – does not change the mass (and thus the weight) of
the water – and this is easily seen by condensing the steam back into water.
Combustion makes things heavier. Why? The answer is that in combustion the material at
hand is combined with oxygen. Thus, burning wood combines the carbon (and other elements)
in the wood with oxygen. Chemistry tells us that Carbon has an atomic weight of 12 and oxygen
has an atomic weight of 16. So, the weight of the burnt wood is really the weight of the ash
(which is the part of wood that doesn’t burn) plus the weight of the CO2 produced by the
combustion. This weight of the CO2 is the weight of each carbon atom combined with two
oxygen atoms. Roughly the mass of the burned wood is (200 pounds of ash + 1800 of carbon X
(12+16 +16)/12). Working through the math yield 6600 pounds of CO2 + 200 of ash for a total
of 6800 pounds.
Every Day Examples. Applying these two lessons to every day examples helps us understand
how it is that we all produce tons of CO2 per year.
- A gallon of gasoline is mostly Carbon (with a little Hydrogen – hence the name hydro
carbon). A gallon of gas weighs about 6 pounds. How much CO2 does it produce?
Burning a gallon of gasoline produces 20 pounds of CO2. This is counter-intuitive to
people for the reasons discussed above – and also- because virtually no one actually
feels the weight of the gasoline in their car. A 15 gallon fill up weights 90 lbs!! and the
resultant greenhouse gas produced when this is burned is about 300 lbs. An average
American driver uses about 600 gallons of gas per year – or 13,200 lbs.
- The average household uses about 7000Kwh per year. This may be expressed as 7 Mega
Watt Hours per year. According to ISO NE (https://www.iso-ne.com/staticassets/documents/2019/04/2017_emissions_report.pdf) Connecticut produces 561lbs
of CO2 per Mega Watt Hour or 3,927 lbs. per year
- A typical home uses 800 gallons of oil (or equivalent) for winter heating. A gallon oil
produces about 22 lbs. of CO2 per gallon or about 17,600 lbs. per year.
The goal of this discussion is help us as consumers and drivers – to connect our behavior to our
Carbon footprint. There are many other carbon dioxide producing activities – which add to the
approximately 17 tons of CO2 – per year – outlined above. The hope is that by “feeling” – as
well as “knowing” our Carbon Footprint – we will become more conscious of our impact on the earth.