Patterns in environmental quality and sustainability Atmosphere and change Describe the functioning of the atmospheric system in terms of the energy balance between solar and longwave radiation. Explain the changes in this balance due to external forcings (changes in solar radiation, changes in the albedo of the atmosphere and changes in the longwave radiation returned to space). Discuss the causes and environmental consequences of global climate change. (4 hours)

Patterns in environmental quality and sustainability Lessons 1 and 2 Core Unit Part 3: Patterns in environmental quality and sustainability Atmosphere and change Describe the functioning of the atmospheric system in terms of the energy balance between solar and longwave radiation. Explain the changes in this balance due to external forcings (changes in solar radiation, changes in the albedo of the atmosphere and changes in the longwave radiation returned to space).

The Earth’s atmosphere In groups you are going to draw a diagram from memory to learn about the different layers that make up the Earth’s atmosphere.

The global heat budget and atmospheric circulation Surface of the sun = 65 million billion sq. Metres Energy sent from each square metre could illuminate 1 million light globes Why do global temperatures vary?

What is going on in this photograph?

The global heat budget and atmospheric circulation IB syllabus requirements: 1. Describe the functioning of the atmospheric system in terms of the energy balance between solar and longwave radiation. 2. Explain the changes in this balance due to external forcings (changes in solar radiation, changes in the albedo of the atmosphere and changes in the longwave radiation returned to space). Using p.102-104 of Planet Geography, and the diagrams, complete the following tasks. Task 1: Find definitions and explanations for the following words: Insolation Long wave radiation Short wave radiation Albedo Task 2: Explain what happens to the energy from the sun when it reaches planet Earth. You need to make reference to: The impact of the atmosphere The impact of the Earth’s surface (including type of surface ,latitude and the shift in wave length as the sun’s energy is reflected back out) Task 3: Look at figure 3.5. Using data, explain what it shows. If there is a net surplus of energy towards the equator and a net deficit of energy towards the polar regions, explain why the equator is not continually warming up and the poles continually cooling down. Task 4: Explain what the greenhouse effect is. Why is it important?

Figure 3.4 Figure 3.4

Info cards for diagram from memory

Atmosphere The atmosphere is like a thin film surrounding the earth and is made up of different layers Half the mass of the atmosphere is found within the lowest 6km. 99% of the atmosphere is contained within the lowest 40km

Troposphere Lowest layer of the atmosphere Contains most of the mass of the atmosphere, including most of the dust, water vapour and pollution Where the weather occurs Heat does not come directly from the UV rays of the sun like in the other layers – it is reflected from the Earth’s surface and clouds. Temperatures fall by approximately 6.5°C every 1,000 metres rise in altitude but this varies. The gases in this layer include nitrogen (78%), oxygen (21%), argon (<1%), carbon dioxide (0.003%). Hydrogen, helium, krypton, methane, ozone, neon and xenon are also present but comprise of only 0.001% Water vapour is also present in this layer but it varies enormously from place to place and day to day.

Stratosphere 20km – 50 km above seal level Concentration of ozone in the stratosphere, which absorbs UV radiation very well. Temperatures rise with increasing altitude in the stratosphere – top part of the layer absorbs higher levels of UV radiation so is warmer – approx 0°C The lower limits of the troposphere (TROPOPAUSE), the temperature is approx -50°C

Mesosphere 50km – 80km above sea level Coldest part – very little cloud, dust, ozone or water vapour to absorb heat from the sun. Has strongest winds in the atmosphere – up to 3,000 km/hour. Comprises the MESOPAUSE – which separates the mesosphere and the thermosphere above it – this is always at a constant -90°C

Thermosphere Highest layer of the atmosphere Extends from approx. 80km ASL to the furthest extents of the atmosphere. Gases here(oxygen, hydrogen, nitrogen) are very thin & similar to a vacuum – only 0.001% of the mass of the atmosphere. Gases here absorb UV radiation from the sun so heat up to high temperatures – 200°C to 1,000°C