GREENHOUSE GASES.

• These are gases that absorb and trap radiation (mainly solar radiation) resulting in increased temperatures of the earth and atmosphere, called the GREENHOUSE EFFECT, or GLOBAL WARMING.

• The primary greenhouse gases in the Earth's atmosphere are;– water vapor, – carbon dioxide, – methane, – nitrous oxide, – CFC, and– ozone

Gas

Formula

Contribution(%)

Water vapor H2O 36 – 72 %

Carbon dioxide CO2 9 – 26 %

Methane CH4 4 – 9 %

Ozone O3 3 – 7 %

SOURCES OF GREENHOUSE GASES.

• NB: In the industrial era, trends in population and human activities (lifestyle) have added greenhouse gases to the atmosphere.

• Carbon Dioxide (CO2): Enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal)

• Chemical reactions (e.g., manufacture of cement).

• Methane (CH4): Methane is emitted during the production and transport of coal, natural gas, and oil.

• Methane emissions also result from decay of organic waste in municipal solid waste landfills.

• Nitrous Oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities.

• Fluorinated Gases: Hydrofluorocarbons and sulfur hexafluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes.

Effects of greenhouse gases on human health.

• Direct Temperature EffectsExtreme heat waves during the summer while producing less extreme cold spells during the winter.

• Indirect EffectsRainfall patterns affected (food security)Cyclones/ storms (Tornadoes)

• Tens of millions of additional people could be at risk of malaria.

• Previously malaria-free areas like Zimbabwe could become prone to the transmission of malaria due to slight temperature and precipitation variations,

• In South Africa the areas prone to malaria could double with 7.8 million people at risk.