4.4 Climate Change

Essential Idea

• Concentrations of gases in the atmosphere affect climates experienced at the Earth's surface.

Understandings

1. Carbon dioxide and water vapour are the most significant greenhouse gases.

2. Other gases including methane and nitrogen oxides have less impact.

3. The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere.

4. The warmed Earth emits longer wavelength radiation (heat).

5. Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere.

6. Global temperatures and climate patterns are influenced by concentrations of greenhouse gases.

7. There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures.

8. Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter.

Applications

1. Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.

2. Correlations between global temperatures and carbon dioxide concentrations on Earth.

3. Evaluating claims that human activities are not causing climate change.

Skills

• None

Guidance

• Carbon dioxide, methane and water vapour should be included in discussions.

• The harmful consequences of ozone depletion do not need to be discussed and it should be made clear that ozone depletion is not the cause of the enhanced greenhouse effect.

Key Vocabulary

• Greenhouse gas

  • Concentration

  • Nitrogen oxide

• Long wave radiation

• Correlation

• Average global temperature