1.3 Greenhouse Gases and the Greenhouse Effect Continued

Greenhouse gases are only transparent to specific wavelengths of radiation.

When the sun’s radiation hits the earth, some of it is absorbed and then released at longer wavelengths which the GHGs block from going into space, which causes the planet to warm.

Water vapour is the most abundant GHG and is responsible for 30-70% of the greenhouse effect, with carbon dioxide contributing 10-30%, methane 5-10% and ozone 3-7%.

Many scientists would agree that human-induced global warming is a product of the Industrial Revolution.

• Since then carbon dioxide emissions have increased 30%, methane 59% and nitrous oxide 15%, which has significantly increased the heat-trapping capabilities of the greenhouse effect

Carbon dioxide is primarily released into the atmosphere through:

•  The combustion of fossil fuels (oil, coal and natural gas)
•  Solid wastes
•  Wood products

Methane is emitted into the atmosphere as a result of:

• Production and transportation of coal, natural gas and oil
• Decomposing organic wastes from landfills
• The raising of livestock
• Rice paddy farming
• Methane also occurs from decomposing organic wastes from landfills, the raising of livestock and rice paddy farming.  CFCs and other halocarbons are also powerful human-made GHGs that are effective heat absorbers

Climate change is the designation given to shifts in either global or regional climate over time.

Changes in climate are measured over various amounts of time and range from decades to millions of years.

These changes may be caused by both natural processes and external forces (human activities).