1. 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

3. Gas Formula Contribution (%) Water vaporH2OH2O36 – 72 % Carbon dioxideCO 2 9 – 26 % MethaneCH 4 4 – 9 % OzoneO3O3 3 – 7 %

4. 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 (CO 2 ): Enters the atmosphere through the burning of fossil fuels (oil, natural gas, and coal) Carbon Dioxide (CO 2 ) Chemical reactions (e.g., manufacture of cement). Methane (CH 4 ): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane (CH 4 ) Methane emissions also result from decay of organic waste in municipal solid waste landfills. Nitrous Oxide (N 2 O): Nitrous oxide is emitted during agricultural and industrial activities. Nitrous Oxide (N 2 O) Fluorinated Gases: Hydrofluorocarbons and sulfur hexafluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated Gases

5. Effects of greenhouse gases on human health. Direct Temperature Effects Extreme heat waves during the summer while producing less extreme cold spells during the winter. Indirect Effects Rainfall 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.