Much has been said about the warming of the planet, and I
already described what scientific experiment must be conducted to prove or
disprove that carbon dioxide is the culprit. This has not been done yet as far
as I know. But whatever the culprit, there is another aspect to the subject
matter that we can examine mathematically to get a sense of what we're looking
at. It would be the question as to whether or not human activities contribute
to the warming of the planet.
Well, the answer is yes, human activities do contribute to
the warming of the planet. For example, when you light a match, the heat that
was in it is now liberated. The science of physics says that the act will
contribute to the warming of the planet. But the question is this: How much
will it contribute as compared to the heat that the planet receives from the
sun? By the same token, how much do all human activities contribute to the
warming of the planet – what you might call heat pollution? We shall, for now,
ignore the heat that comes from the processes undergoing inside the planet
which cause things like volcanic lava and geothermal steam to erupt.
To evaluate the amount of heat that comes from the sun as
compared to what human activities produce, we can do a crude experiment and a
thought experiment. Combining results from the two, we can get – not an
accurate answer – but a sense of the dimensions we are dealing with.
The first thing we observe is that the total consumption of
energy resources by the entire planet comes to the approximate equivalent of
1.5 million tons of oil every hour. Since a ton of oil yields about 10,000 kw/h
of heat, the consumption of resources comes to the equivalent of about 15
billion kw/h.
To see how that compares to what comes from the sun, we go
out on a summer day when there is no wind, and expose the back of the hand to
the sun for a few minutes. We feel the heat, and try to replicate that feeling
with a controlled experiment whose data we can measure. Seeing that the back of
a human hand is a square of about 4x4 inches or 10x10 centimeters, we calculate
that the average human hand has a surface area of about 100 square centimeters.
We now think up an experiment in which we use light produced
by an incandescent light bulb to replicate the heat sensation we felt coming
from the sun. To this end, we construct a square kind of bell that has the
dimensions 10x10 centimeters at the base – the same dimensions as the back of
the human hand. We give the inside of the bell a reflective coating and place
the light bulb inside it to shine light on the back of the hand.
After a few trials and errors, we find that it takes a bulb
of 100 watts to replicate what we felt from the sun. This means that every
square centimeter of the hand is receiving 1 watt of heat from the light bulb.
It also means that a direct exposure to the sun has the effect of subjecting a
square centimeter of the earth to 1 watt of heat equivalent. To digress for a
moment, only a tenth of that is usually converted into electricity by solar
cells.
We now seek to find how much solar energy hits the earth.
Because the earth is a rotating sphere, only one spot near the equator receives
the full force of the sun's energy. That force diminishes as we move away from
the spot, but we don't have to worry because we can imagine slicing the earth
to expose a flat circle that faces the sun permanently. Whatever energy the
circle receives is how much energy will be shared by the entire planet,
whatever its shape and however much it rotates.
So we begin to calculate. The circle has a radius of about
6366 kilometers or 636.6 million centimeters. Its surface area will be 1273
quadrillion square centimeters; and will receive 1273 quadrillion watts of heat
energy per hour from the sun, which translates into 1273 trillion kw/h. This is
about 84,867 times as much as the earth currently consumes in all forms of
energy.
Now that we have this ratio, we deduce that a day's worth of
sun energy is equivalent to 84,867 days of non-renewable energy or 233 years
worth of heat pollution.