Human Activity and Greenhouse Gases

- growing evidence over the last few decades suggest that current warming trend is due to humans (anthropogenic)

a. Industrialization- the industrial revolution began in the late 1700’s was possible due to

the burning of fossil fuels (coal, oil and natural gas) - this placed a high amount of gasses and pollutants into the atmosphere

Human Activity and Greenhouse Gases

b. Deforestation- an decrease of forests due to logging and farming

Effect: less carbon dioxide (CO2) absorbed by trees leading to a greater concentration of the gas in the atmosphere

Greenhouse Gases1. Water Vapour (H2O)- 1 – 4% of Earth’s atmosphere- responsible for 65 to 85% of the greenhouse effect- however, since not added to or removed from the atmosphere by

humans it is not considered a “pollutant”

Greenhouse Gases2. Carbon Dioxide (CO2)- responsible for 72% of “pollutant” emissions- has risen from 315 ppm in 1960 to 370 ppm in 2000

Greenhouse Gases3. Methane (CH4)- responsible for 18% of “pollutant” emissions - created by the decomposition of organic material

Greenhouse Gases4. Nitrous Oxides (N2O)- responsible for 9% of “pollutant” emissions- formed when nitrogen-rich compounds are broken down by

bacteria

Greenhouse Gases5. Fluorocarbons- chemicals used as coolants in refrigerators and air conditioners- responsible for destroying the ozone layer