Climate 2.2 Anthropogenic factors contributing to climate change

Front

Explain what is the greenhouse effect.

Back

1. Shortwave radiation from the sun travels towards the earth

2. Most shortwave radiation is absorbed by the earth's surface and some is absorbed and reflected by clouds

3. The earth emits longwave radiation back into space

4. Some longwave radiation is absorbed by greenhouse gases and re-emitted back onto earth, keeping the earth warm

Front

How does the earth remain warm in the day and at night?

Back

Day: Predominantly through shortwave radiation from the sun.

Night: Predominantly longwave radiation that is emitted from the earth, and re-emitted back into earth by greenhouse gases

Front

Explain what is the enhanced greenhouse effect.

Back

1. The enhanced greenhouse effect refers to the increase in global temperature due to the increase in greenhouse gases in the atmosphere caused by human activities

2. With more greenhouse gases in the atmosphere, less heat escapes the atmosphere and more heat (longwave radiation) is re-emitted into earth

Front

What are the two anthropogenic factors leading to the enhanced greenhouse effect?

Back

1. Burning of fossil fuels
2. Changing landuse - Deforestation to clear forested land for Agriculture, Industries and Urbanisation

Front

Describe how deforestation contributes to the enhanced greenhouse effect.

Back

1. Large-scale removal of forests reduces the number of trees that absorb carbon dioxide through photosynthesis

2. When trees are cut down or burned, the stored carbon is released back into the atmosphere as carbon dioxide

3. Clearing of trees exposes the soil to sunlight, which increases the rate of carbon oxidation

eg. Tropical deforestation contributes to 20% of greenhouse gas emissions

Front

Describe how agricultural activities contributes to the enhanced greenhouse effect.

Back

1. Burning of fossil fuels to produce energy for farm machinery

2. Nitrogen in chemical fertilisers converts to nitrous oxide

3. Livestock rearing and natural decomposition releases methane

eg. Agriculture contributes to about 30% of global greenhouse gas emissions

Front

Describe how industries contributes to the enhanced greenhouse effect.

Back

1. Burning of fossil fuels to produce energy for machinery and factory processes


eg. Industries contributes about 43% of global greenhouse gas emissions

Front

Describe how urbanisation contributes to the enhanced greenhouse effect.

Back

1. Fossil fuels are burned to power the high concentration of vehicles and household activities eg. Heating, cooling & lighting


eg. Cities consume about 78% of world's energy and contribute to large amounts of greenhouse gases