Lesson 18 – pages 9-10

 To learn that climate has always changed naturally.  To learn that there have been ice ages and warm periods over the past 2 million years.  To learn the evidence for this.  Key Skills = Communication & Number

 Over the past 400,000 years when were temperatures warmer than today?  Why does this encourage climate change sceptics?

 Scientific tests on ice cores from the Antarctic.  Remains of animals in the mud of the sea floor.  On land, pollen and beetle remains shows us the temperatures when a layer of soil formed.  Old land forms formed by ice and modern glacier retreat.

 What evidence is there that the global climate changes?  Natural cycles exist – approximately 10,000 years warm (now) and 100,000 years cold (ice age). Describe the pattern on the graph.

Heat travels from the Sun in the form of shortwave radiation. Heat warms the surface of the Earth Heat is given off as longwave radiation Some longwave radiation gets absorbed by greenhouse gasses.

 Finish off your drawing.  Write a paragraph to explain the greenhouse effect.