Formation of Fossil Fuels


Uploaded by Etheoperatorsmanual on 09.04.2012

Transcript:
So why are fossil fuels such a powerful,
but ultimately problematic, source of energy?

Conditions on the waterways of today's Louisiana
help us understand how fossil fuels are made
and why they're ultimately unsustainable.
Oil, coal and natural gas are made from things,
mostly plants, that lived and died long ago.
It's taken hundreds of millions of years
for nature to create enough of the special conditions
that save the carbon and energy in plants
to form the fossil fuels that we use.
Here's how it works...
Plants, like these tiny diatoms
encased in silica shells,
grow in the upper layers of lakes and oceans,
using the sun's energy to turn carbon dioxide and water
into more plants.
When they die, if they are buried where
there's little oxygen to break them down,
their chemical bonds retain the energy that began as sunlight.
If enough carbon-rich matter
is buried deeply enough, for long enough,
the Earth's heat and pressure turn it into fossil fuel,
concentrating the energy that once fed the growing plants.
Vary what goes into Earth's pressure cooker,
and the temperature,
and you end up with the different kinds of fossil fuel.
Woody plants make coal.
Slimy plants, algae, will give you oil,
and both of 'em give rise to natural gas.
The fossil fuels formed over a few hundred million years,
and we're burning them over a few hundred years,
and if we keep doing that,
sooner or later, they must run out.
But there's a bigger problem with fossil fuels.
As we've seen, they're made of carbon primarily,
and when you burn them, add oxygen
and that makes CO2 that goes in the air.
We're reversing the process by which they formed.
And if we keep doing this,
it must change the composition of Earth's atmosphere.
(jet engine roaring)