Lecture 15 - Introduction to greenhouse gasses and the greenhouse effect

Introduction

This tutorial provides an overview of greenhouse gases and the greenhouse effect, based on a lecture by Mel Strong. Understanding these concepts is crucial for grasping the impact of human activity on climate change and for making informed decisions about environmental protection.

Step 1: Understand Greenhouse Gases

• Definition: Greenhouse gases (GHGs) are gases in the Earth's atmosphere that trap heat.
• Common GHGs:
  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Nitrous oxide (N2O)
  • Water vapor (H2O)
• Sources: GHGs can originate from natural processes and human activities, such as burning fossil fuels, deforestation, and agricultural practices.

Step 2: Learn About the Greenhouse Effect

• Process: The greenhouse effect occurs when GHGs absorb and re-radiate infrared radiation from the Earth's surface.
• Importance: This process keeps the Earth warm enough to sustain life. However, an excess of GHGs enhances this effect, leading to climate change.
• Visualize: Imagine the Earth surrounded by a blanket of GHGs that allows sunlight in but traps heat, similar to how a greenhouse works.

Step 3: Compare the Strengths of Different Gases

• Global Warming Potential (GWP): This is a measure used to compare the warming effects of different GHGs over a specific timeframe, typically 100 years.
• Key Points:
  • CO2 is used as the baseline (GWP of 1).
  • Methane has a GWP of about 25, meaning it is 25 times more effective than CO2 at trapping heat.
  • Nitrous oxide has a GWP of about 298.

Step 4: Convert Greenhouse Gases to CO2 Equivalent

• Purpose: Converting GHG emissions to CO2 equivalent helps in understanding their overall impact on climate change.
• Calculation Steps:
  1. Identify the amount of each GHG.
  2. Multiply the amount by its GWP.
  3. Sum the results to get the total CO2 equivalent.
• Example:
  • If you have 10 tons of CH4, the calculation would be:

    CO2 Equivalent = 10 tons CH4 * 25 (GWP) = 250 tons CO2e
    

Conclusion

Understanding the role of greenhouse gases and the greenhouse effect is essential for addressing climate change. By comparing the strengths of different gases and converting emissions to CO2 equivalents, we can better assess their impact. Next steps could include exploring strategies for reducing GHG emissions or delving deeper into climate science through additional resources or courses.