Greenhouse gases

Greenhouse gases provide a natural blanket over the Earth and keep it about 33 degrees Celsius warmer than it would have been without these gases in the atmosphere. This phenomenon is called the greenhouse effect.

Primary greenhouse gases

The primary greenhouse gases in the Earth's atmosphere are water vapour (H₂O), carbon dioxide(CO₂), nitrous oxide (N₂O), methane(CH₄) and ozone (O₃). Some greenhouse gases in the atmosphere are entirely human made such as the halocarbons and other chlorine and bromine containing substances, dealt with under the Montreal Protocol.

Beside CO₂, N₂O and CH₄, the Kyoto Protocol deals with the greenhouse gases:

• sulphur hexafluoride (SF6)
• hydrofluorocarbons (HFCs)
• perfluorocarbons (PFCs)

The impact of rising emissions

Over the past century, the temperature of the earth has increased by about 0.5 degrees Celsius. Several scientists believe this is because of an increase in concentration of the main greenhouse gases: carbon dioxide, methane, nitrous oxide, and fluorocarbons. People are now calling this climate change over the past century the beginning of global warming.

It is feared that if people keep producing such gases at increasing rates, the results will be negative in nature, such as more severe floods and droughts, increasing prevalence of insects, sea levels rising, and Earth's precipitation may be redistributed. These changes to the environment will most likely cause negative effects on society, such as lower health and decreasing economic development. However, some scientists argue that the global warming we are experiencing now is a natural phenomenon, and is part of Earth's natural cycle. Presently, nobody can prove if either theory is correct, but one thing is certain; the world has been emitting greenhouse gases at extremely high rates and has shown only small signs of reducing emissions until the last few years. After the 1997 Kyoto Protocol, the world has finally taken the first step in reducing emissions.

Did You Know?

• In order to stabilize atmospheric concen-trations of greenhouse gases where they are today, global CO₂ emissions would have to be cut by 50-60%.
• Methane is a very powerful greenhouse gas because it can retain 21 times more heat than CO₂.
• Even if emissions of greenhouse gases were to stop immediately, earlier emissions would continue to affect climate for centuries to come.
• One third of greenhouse gas emissions in Quebec are the direct result of human activities.
• In summer, the parts of Quebec most affected by violent weather phenomena are the regions of Montréal and Montérégie, where over 20 events - violent winds, torrential rains and flooding, and hail - are reported each year.
• Improving energy efficiency is the fastest, cheapest, and surest way to reduce greenhouse gas emissions.
• Every litre of gasoline used in a car produces almost 2.5 kilograms of CO2.
• As the Earth warms, temperature changes are anticipated to be greater in the North, and greater in winter than in summer.
• Winter and summer temperature extremes are responsible for more deaths than are more violent weather events such as tornadoes, blizzards or floods.

References

• What are Greenhouse Gases
• Climate Change Impacts and Adaptation Program