I. Is the Earth warming up?
is the observation part of a natural cycle?
II. What is the cause?
natural? or human? what kinds of gases?
III. What are the effects of the warming?
are the effects good or bad, if bad, what are they?
IV. What can we do to stop it?
do we have alternative energy sources?
The Earth has warmed ~0.5°C over past century
CO2 level increased from 330 ppm to 370 ppm
There are natural cyclic variations in our atmosphere
Biggest greenhouse gas is actually water vapor