9.2 - Carbon Dioxide & Methane as Greenhouse Gases

What is the greenhouse effect?

Greenhouse gases in the atmosphere maintain temperature on Earth high enough to support life.

What are greenhouse gases?

They allow short wavelength radiation from the sun to pass through the atmosphere to the atmosphere to the Earth’s surface, but absorb the outgoing long wavelength radiation from the Earth causing an increase in temperature.

Give examples of greenhouse gases.

Water vapor, carbon dioxide, and methane.

Why is the greenhouse effect necessary for life?

The greenhouse effect is a natural phenomenon. Without it, the Earth would be too cold for life to exist.

How have human activities led to an increase in greenhouse gases?

• Carbon dioxide - combustion and deforestation.

• Methane - increased farming and decomposition in landfills.

What are the potential effects of global climate change?

• Sea level rise, which may cause flooding and increased coastal erosion.

• More frequent and severe storms.

• Changes in the amount, timing, and distribution of rainfall.

• Temperature and water stress for humans and wildlife.

• Changes in the food-producing capacity of some regions.

• Changes to the distribution of wildlife species.

What is a carbon footprint?

A carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service, or event.

What actions can be taken to reduce a carbon footprint?

• Increased use of alternative energy supplies.

• Energy conservation.

• Carbon capture and storage (where CO is trapped in solvents and stored underground).

• Carbon taxes and licenses.

• Carbon off-setting including through tree planting.

• Carbon neutrality - zero net release.

What are the problems of reducing the carbon footprint?

• Scientific disagreement over causes and consequences of global climate change.

• Lack of public information and education.

• Lifestyle changes (people don’t want to give up their cars).

• Economic considerations (it will cost money).

• Incomplete international cooperation.