7. Climate Change

Weather vs. Climate

• Weather: Short-term atmospheric changes (temperature, precipitation).

• Climate: Average weather conditions on Earth.

Global Warming and the Greenhouse Effect

• Solar radiation passes through the atmosphere and warms the Earth's surface.

• Earth re-radiates energy as infrared radiation (heat).

• Greenhouse gases absorb and re-emit infrared radiation, warming the Earth.

Greenhouse Gases

1. Carbon dioxide (CO2): Most abundant greenhouse gas.

2. Methane (CH4): From biological sources and fossil fuel burning.

3. Nitrous oxide (N2O): From fossil fuels and fertilizers.

4. Chlorofluorocarbons (CFCs): From refrigerators, cleaning solvents, and propellants.

Effects of Global Warming and Climate Change

• Rising sea levels: Causes beach and coastal wetland erosion.

• Loss of coastal areas: Affects island nations and countries like Bangladesh.

• Water cycle disruption: Causes droughts and flooding.

• Impacts: Navigation, hydropower, water quality, health, ecosystems, agriculture, and food supply.

Slowing Climate Change

• Reduce fossil fuel use.

• Improve energy efficiency.

• Shift to renewable energy resources.

• Reduce deforestation.

• Remove carbon dioxide from the atmosphere (e.g., smokestack emissions, carbon sequestration).