Human Causes of Climate Change

Question 1

all human causes (5)

Answer 1

• increase in CO2 emissions
• increase in methane emissions (landfill & agriculture)
• increase in nitrous oxide emissions (vehicles)
• chlorofluorocarbon emissions
• reduction in carbon sinks (deforestation)

Question 2

increase in CO2 emissions

Answer 2

• burning fossil fuels to generate electricity releases CO2 into the atmosphere
• a rise in global population has led to a rise in demand for electricity, therefore CO2 emissions from energy production have increased significantly

Question 3

reduction in carbon sinks (deforestation)

Answer 3

• vegetation has been removed for practices like agriculture and urban growth
• trees act as a carbon store, removing CO2 from the atmosphere
• removal of trees reduces capacity for storage of CO2
• deforestation by burning trees releases huge amounts of CO2, contributing to the greenhouse effect

Question 4

Increase in methane emissions (landfill sites)

Answer 4

methane is released from decomposing waste in landfill sites, which accounts for almost a third of the UK’s methane emissions

Question 5

increase in methane emissions (agriculture)

Answer 5

• rise in global population has led to a rise in demand for beef; cows act as ruminants, and release methane during digestion
• methane is produced in rice paddy fields as microbes underwater break down organic matter
• methane is more powerful than carbon dioxide, making it a powerful greenhouse gas

Question 6

Increase in Nitrous Oxide emissions (vehicles)

Answer 6

• increased car ownership as a result of increased wealth
• vehicles emit nitrous oxide, which is a powerful greenhouse gas
• increased car ownership also increases demand for fossil fuels like petrol and diesel

Question 7

chlorofluorocarbon emissions

Answer 7

• CFCs are emitted by old refrigerators, air conditioning systems and spray cans
• CFCs absorb heat trying to leave the atmosphere, contributing to climate change