Unit 23
Ice and climate.
Ice sheets that flow and lower the sea, the orbital beat of the ice ages, and the greenhouse effect.
The unit, lesson by lesson
Lessons
3 lessons · 19 practice questions · about an hour
Glaciers and ice sheets
Snow that outlasts the summer piles up into ice, and the ice flows like a very slow river. See how the summer sets an ice sheet's size, where the ice flows fastest, how far it pushes the ground down and how much water it takes from the sea.
Ice ages and Milankovitch cycles
Three slow changes in the Earth's orbit and axis change the summer sunlight in the far north. Work out the distance to the Sun and the gap in sunlight, see why the summer and not the winter decides the ice, and line summer sunlight up with the ice ages of the last 400,000 years.
Climate
Sunlight comes in, heat goes out, and a few gases in the air decide how much of it escapes. Work out how cold the Earth would be with no greenhouse gas, how much heat the extra carbon dioxide holds back, why each doubling adds the same, and how much warmer that makes us.