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Lesson 6
Key Idea 1: Water Vapour

Though water vapour may not be the first gas that comes to mind when you think about climate change, it is actually the most abundant greenhouse gas in our atmosphere! Responsible for over half of Earth's greenhouse forcing, water vapour plays a vital role in keeping Earth warm enough to sustain life.


Open the IR Windows learning tool and review the infrared absorption spectrum of water vapour. Answer the following questions:

  1. Why are the IR window regions important?
  2. How are the regions in which water vapour absorbs IR related to its significance as a greenhouse gas?