FOSSIL FUELS

What are fossil fuels?

are energy-rich substances formed from ancient life that got buried under tons of sediment and slowly “cooked” by heat and pressure over millions of years.
Think of them like nature’s slow-cooked leftovers.

examples of fossil fuels

• Coal (from ancient swamp plants)

• Oil (from dead plankton and algae in oceans)

• Natural gas (methane produced alongside oil or coal)

• Petroleum products (gasoline, diesel, jet fuel — all derived from crude oil)

why are fossil fuels energy dense

they contain stored solar energy from millions of years ago. Plants photosynthesized sunlight → stored that energy → became fossil fuels

How fast does humanity consume fossil fuels?

We burn ~300 tons of fossil fuels every single second globally.
Imagine:

• An Olympic swimming pool of oil every few minutes

• A mountain of coal burned daily

This is why fossil fuel use dominates climate discussions.

What do we use fossil fuels for?

Pretty much everything modern life depends on:

• Electricity (coal, gas)

• Transportation (gasoline, diesel, jet fuel)

• Heating (natural gas)

• Material manufacturing (plastics, fertilizers, asphalt)

Without fossil fuels, we wouldn’t have:

• Cars, planes

• Plastic

• Steel

• Asphalt roads

• Modern agriculture

They powered the entire Industrial Revolution.

Why have US electric emissions declined in recent decades?

we shifted away from the dirtiest fuels (coal and oil) toward:

• Natural gas

• Wind

• Solar

• Hydropower

Natural gas produces about half the CO₂ of coal, and renewables produce almost none during operation.

So even though our electricity use increased, emissions decreased.

Why do energy transitions take so long (50–300 years)?

imagine trying to change:

• Every power plant

• Every car

• Every industrial process

• Every home’s heating system

It’s like turning a giant ship — slow, expensive, and full of inertia.
Historically:

• Coal → wood took ~300 years

• Oil → coal took ~150 years

• Natural gas only surpassed coal in 2015

Why did civilization first switch to coal?

We were running out of whale oil, which was used for lamps.
Coal became a necessary backup plan for light and heat.

Later, coal powered:

• Steam engines

• Trains

• Factories

• Electricity generation

What is coal made of?

formed from ancient swamp plants that fell into oxygen-poor water and didn’t fully decompose. Over millions of years, layers of sediment compressed them and heated them → forming coal.

Types of coal from least to most pure

• Lignite – soft, crumbly, lowest energy

• Subbituminous – more energy

• Bituminous – common, higher energy

• Anthracite – hardest, cleanest-burning, highest energy

Environmental impacts of coal mining

• Habitat destruction
  Entire mountains can be removed (mountaintop removal).

• Acid mine drainage

• Toxic slurry ponds

• Blackwater from mines

• Miners’ health risks

What causes acid mine drainage — and why does it turn water orange?

Coal contains pyrite (fool’s gold).
When exposed to:

• Oxygen

• Water

→ pyrite reacts and forms sulfuric acid.

The acid dissolves metals (iron, aluminum, copper) → turning streams bright orange like rust.

It kills fish, plants, and creates long-term contamination.

How do we fix acid mine drainage?

We add crushed limestone (calcium carbonate).
This neutralizes acid the same way TUMS neutralizes stomach acid.
It doesn’t restore streams completely but prevents further damage.

Environmental problems with burning coal

• SO₂ → acid rain

• NOx → smog and acid rain

• Fly ash → huge waste storage problem

• Mercury emissions → bioaccumulate in fish

• CO₂ → climate change

How does acid rain form?

Burning coal releases:

• SO₂ (sulfur dioxide)

• NOx (nitrogen oxides)

These gases rise into the atmosphere, mix with water vapor, and form sulfuric and nitric acid.
Clouds carry it hundreds of miles → acidic rain falls on forests, lakes, buildings.

Effects:

• Fish die

• Forests weaken

• Monuments corrode

• Soil nutrients wash away

Solutions to acid rain

• Scrubbers use crushed limestone to remove sulfur gases

• Filters remove particulates

• Transition to gas and renewables