Human Causes of Climate Change

Question 1

Increased fossil fuel consumption

Answer 1

Burning hydrocarbons produces carbon dioxide and water vapour.
37 billion tonnes of carbon dioxide are emitted to the atmosphere every year by hydrocarbons alone.
Carbon dioxide gas absorbs heat from the Sun so less heat escapes back into the atmosphere thus increasing global temperatures.
Eg: Increased car ownership.

Question 2

Deforestation

Answer 2

Deforestation in tropical rainforests contributes to increased levels of Carbon Dioxide in our atmosphere.
If the trees are burned once cut down, Carbon Dioxide is released.
Additionally, if there are fewer trees around the world to absorb Carbon Dioxide this leads to the further build-up of the gas in our atmosphere.

Question 3

Cattle ranching

Answer 3

Demand for beef is higher than ever before due to the world’s increasing population
Their grassy diet and multiple stomachs cause them to produce methane which they exhale with every breath.

Question 4

Paddy fields

Answer 4

Paddy fields account for around 20% of human related emissions of methane.
In places like China and India, rice is a staple food so farmers grow large quantities of it in flooded paddy fields.
Methane is produced by microbes underwater as they help to decay any flooded organic matter.

Question 5

Landfill sites

Answer 5

Humans produce a large amount of waste and most of this ends up in landfill sites.
Due to waste slowly decaying and breaking down underground, methane can be released for many years, even after a landfill site has been closed.

Question 6

Fridges and AC units

Answer 6

Chlorofluorocarbons (CFC’s) are greenhouse gasses made up of chlorine, fluorine and carbon.
Refrigerators which are not disposed of correctly release CFCs when the foam insulation inside them is shredded.
Air-conditioning – the coolants used in air conditioning systems create CFCs, which must be disposed of correctly

Question 7

War

Answer 7

Bombs, atomic testing etc. creates a large amount of dust which is thrown up into the atmosphere.
Much like ash from volcanic eruptions, this dust can reduce the insolation received at the Earth’s surface, thus reducing temperatures.