insolation = incoming solar radiation

The atmosphere is an open energy system receiving energy from both the sun and the earth.

Incoming radiation from the sun is short wave, outgoing radiation is long wave.

The sun's energy drives all weather systems and climates. Most is absorbed in tropical latitudes and redistributed to polar latitudes.

TASK:

1. Watch video and make notes

2. Read pp 426-433 and add to your notes

natural vs. enhanced greenhouse effect

Natural Greenhouse Effect

Earth receives energy from the Sun in the form of ultraviolet, visible, and near-infrared radiation. About 26% of the incoming solar energy is reflected back to space by the atmosphere and clouds, and 19% is absorbed by the atmosphere and clouds. Most of the remaining energy is absorbed at the surface of Earth. Because the Earth's surface is colder than the Sun, it radiates at wavelengths that are much longer than the wavelengths that were absorbed. Most of this thermal radiation is absorbed by the atmosphere and warms it. (Source)

The greenhouse effect is a natural process that enables life to exist on earth.

However, human activity is increasing the natural process, warming the climate and contributing to global warming and climate change.

This is the enhanced greenhouse effect.

TASK: Access the resources above. Draw a labelled diagram explaining the natural greenhouse effect. Write a paragraph explaining how human activity has created the enhanced greenhouse effect.

GREENHOUSE GASES

Earth's Atmospheric energy balance

PLENARY

Explain the energy flows involved in the greenhouse effect. [5 marks]

TASK 1: CHANGES IN THE GLOBAL ENERGY BALANCE

1. Draw labelled diagrams to explain the following causes of change in the global energy balance:

   • Variations in solar radiation:

     • Milankovitch Cycles

     • Global Dimming from Volcanic Eruptions

   • Albedo changes

   • Methane gas release

SOLAR RADIATION VARIATIONS

Milankovitch Cycles

Global Dimming from Volcanic Eruptions

Terrestrial Albedo Change & Positive Feedback Loops

TASK 2: FEEDBACK LOOPS

Watch the videos below and make notes on the different examples of feedback loops

Fossil fuel emissions from human activity are driving up Earth’s temperature—yet something else is at work. The warming has set in motion nature’s own feedback loops which are raising temperatures even higher. The urgent question is: Are we approaching a point of no return, leading to an uninhabitable Earth, or do we have the vision and will to slow, halt, and reverse them? (Source)

TASK 3: EXAM PRACTICE

Write responses to the practice exam questions below.

The graph shows global temperature changes since 1850.

State one natural external forcing which could have influenced the changes in temperature shown on the graph [1 mark].

Using a diagram, explain the relationship between atmospheric greenhouse gases and the temperature of the Earth’s surface [5 marks].

Explain two factors, other than greenhouse gas release, that cause changes to the global atmospheric energy balance (3 + 3 marks)