6.1 Introduction to the atmosphere

Objective notes

4 learning objectives

6.1.1Atmosphere boundary

• Between Earth and space

• Outer limit of biosphere

• Composition and processes support life

6.1.2Atmospheric circulation

• Differential heating creates tricellular model

• Redistributes heat from equator to poles

6.1.3Greenhouse gases and aerosols

• Absorb and re-emit infrared radiation

• GHGs: water vapour, CO₂, methane, nitrous oxides

• Aerosols: black carbon

6.1.4Greenhouse effect

• Keeps Earth warmer than otherwise

• Natural process enabling life

• Enhanced greenhouse effect: human GHG accumulation → global warming

• Climate change: broader range of resulting changes