Focused Exam 3 Set — Chunk 5

Main source of greenhouse gas emissions

Human activities, especially burning fossil fuels for electricity, transportation, industry, and agriculture.

Fossil fuels

Energy sources formed from ancient organic matter over millions of years.

Why fossil fuels are nonrenewable

They take millions of years to form and cannot be replaced on a human timescale.

Three main fossil fuels

Oil, coal, and natural gas.

Oil

A liquid fossil fuel refined into products like gasoline, diesel, and jet fuel.

Main use of oil

Transportation.

Coal

A solid fossil fuel used for electricity, heating, and industrial processes.

Natural gas

A gaseous fossil fuel made mainly of methane and used widely for electricity and homes.

Which greenhouse gas is abundant in natural gas

CH4, or methane.

Fracking

A method of hydraulic fracturing used to extract natural gas from shale and other rock formations.

One risk of fracking

It can trigger shallow earthquakes and mass movements.

Direct fossil fuel use

Burning fossil fuels directly for energy, such as driving or heating a home.

Indirect fossil fuel use

Using fossil fuels as materials in products like plastics, fertilizer, concrete, and clothing.

Renewable energy

power generated from natural, constantly replenished sources that never run out, such as sunlight, wind, and water.

Examples of renewable energy

Solar, wind, hydro, geothermal, and biomass.

Green energy

A subset of renewable energy with the greatest environmental benefit.

Nuclear power

Energy produced from splitting heavy atomic nuclei, usually uranium, to generate electricity.

Is nuclear renewable

No, because uranium is nonrenewable.

Is nuclear clean energy

It is often treated as clean energy because it is low carbon, but it is not renewable.

Carbon footprint

The greenhouse gas impact of a person, company, or country.

How to lower carbon footprint

Use less energy, use public transportation, waste less, eat less meat, and support green energy.

Trade-off between energy types

Every energy source has pros and cons, so the key is comparing emissions, reliability, risk, and renewability.

Energy trend idea

Some countries are increasing renewables while still relying heavily on fossil fuels, so energy transitions involve trade-offs.

Clean energy vs green energy

Clean energy focuses on lower emissions, while green energy is the renewable subset with the greatest environmental benefit.

Renewable

Energy that “comes back” naturally. Energy from natural sources that can be replaced over time, like sunlight, wind, and water.

An example is Solar panels use sunlight to make electricity.