The Average Temperature on Planet Earth Is Higher Than You

Multiple Choice

The average temperature on planet Earth is higher than you would expect just from the heating of sunlight alone. What is the explanation for this?

A) solid material hitting the Earth from space heats it up
B) carbon dioxide (and other gases) in the atmosphere cause a greenhouse effect
C) the rubbing of the continental plates warms up the Earth's surface
D) the heat given off by living things makes our planet warmer
E) we have no explanation for this higher temperature and that has scientists worried
Section 8.5: Cosmic Influences on the Evolution of Earth