I beleive global warming is true, we definately polute too much. I feel there is some uncertainty about what is happening. I feel there is two things happening in our atmosphere CO2 is up but also dust and soot particles is up during times of mass pollution. CO2 causes temp. to rise while particles causes temp. to decrease. We say global warming is man made presently because there is no other significant pollution causes in the world right now. So we have these two factors in our atmosphere caused by pollution but work against each other. When particles are really abundant like during industrial boom, temp will fall and during industrial decline particles will settle and decrease and the CO2 left will cause temp. to rise, but this is still very dangerous if these to factors are high because of the uncertainty and unpredictability of our climate.