Greenhouse Gases & Human Activity

Composition of the Atmosphere

Mostly made of nitrogen gas & oxygen gas

Greenhouse Gases

Gases that absorb and re-emit infrared radiation Water vapour Carbon dioxide Methane Nitrous oxide Ozone CFCs

Greenhouse Gases

Sources vs. Sinks Source: adds greenhouse gases to

the atmosphere

Sink: absorbs greenhouse gases from the atmosphere

Natural or caused by human activities

Water Vapour – Sources & Sinks

Carbon Dioxide – Sources & Sinks

Natural sources include volcanic eruptions & cellular respiration

Methane – Sources & Sinks

Nitrous Oxide – Sources & Sinks

Produced naturally by nitrogen-fixing bacteria

Ozone Ozone (O3) is located in the

stratosphere & makes up the ozone layer which blocks harmful UV radiation

Ozone hole in Antarctic

Ground-level ozone forms smog

CFCs Leading cause of ozone depletion in

the ozone layer

Anthropogenic Greenhouse Effect

Human activities have significantly increased levels of greenhouse gases since 1750

Anthropogenic Greenhouse Effect

Increase in global average temperatures

Global Warming Potential (GWP)

Ability of a substance to warm the atmosphere by absorbing thermal energy

The contribution of a particular gas to global warming depends on:• the concentration of the gas in the

atmosphere• the ability of the gas to absorb heat• the length of time the gas remains in the

atmosphere

Global Warming Potential (GWP)

Sources of GHG Emissions in Canada

Sources of Personal GHG Emissions in Canada

Homework Read page 331 Complete Gizmo on Greenhouse

Effect Page 332 #3, 4, 8