H Geography - Global Issues - Global Climate Change - Causes of Climate Change

What are the two types of causes of climate change?

The two types of causes of climate change are;

• Physical

• Human

What are the physical causes of climate change?

The physical causes of climate change are;

• Milankovitch’s theory is a theory that states there are changes in the earths orbit and tilt that alter the amount of energy reaching the Earth. Every 41,000 years there is a change in the tilt of the Earth’s axis. A greater tilt results in more sunlight in polar regions. Over a 97,000 year cycle the Earth’s orbit stretches.

• Global temperatures can be raised by peaks of sunspot activity which follow an 11 year pattern.

• After volcanic eruptions, large amounts of dust and droplets of sulphur may absorb and reflect the suns rays. This lowers the Earth’s temperature. This occurred when Krakatoa erupted, it cooled the average global temperature by 0.6°C for months after the eruption.

• Retreating ice caps release additional fresh water leading to changes in oceanic circulation. Melting of ice caps also reduces the albedo effect as reflection has decreased as more land is exposed.

• Methane is released from melting permafrost

What are human causes of climate change?

Human causes of climate change are;

What are the four gases that contribute to climate change?

The four gases that contribute climate change are;

• CO₂

• CH₄

• N₂O

• CFCs

In what ways is CO₂ contributing to climate change?

CO₂ is contributing to climate change because;

• Burning fossil fuels such as coal, oil, and natural gas release CO₂ into the atmosphere

• Coal is being used increasingly to power factories and generate electricity in power stations to heat homes.

• Increased car ownership has resulted in more petrol and diesel being used to fuel cars. Therefore more CO₂ is produced

• Deforestation has resulted in less CO₂ being absorbed. Burning of forests rapidly releases more CO₂.

How is CH₄ contributing climate change?

CH₄ is contributing to climate change because;

• CH₄ is released from landfill sites as waste decomposes and when the earth is drilled for natural gas

• In padi fields, CH₄ is produced by microbes underwater as rice plants decay. Rice production is increasing to meet the demand in rapidly growing countries.

• The increasing demand for beef has resulted in more CH₄ being released by belching cattle and from animal dung.

• CH₄ is 20x as effective in trapping heat than CO₂, it accounts for 20% of the enhanced greenhouse effect and it remains in the atmosphere for 11-12 years.

How are nitrous oxides contributing to climate change?

Nitrous oxides are contributing to climate change because;

• Increased car exhaust emissions, especially from diesel cars, have resulted in more nitrous oxides being released.

• The increased production of fertilisers also adds to the amount of nitrous oxides in the atmosphere.

• Nitrous oxides are 200-300 times more effective at trapping heat than CO₂.

How are CFCs contributing to climate change?

CFCs are contributing to climate change because;

• Fridges which are not disposed of correctly release CFCs when the foam insulation inside them is shredded.

• They have long life times of a 100 years and are 10,000 times more effective than CO₂ at trapping heat in the atmosphere.