My specialty would be about the water problems in agriculture. I would focus on areas such as California and show how farmers are using too much water. I could also show what happens when they let all of their waste water flow down stream. The link I am posting is an example of water problems in a town in California in 2009.
View our PSAs
The Four Rs: http://web.suffieldacademy.org/~11bko/4_Rs.mov
The New World: http://web.suffieldacademy.org/~11kk/thenewworld.mov