What are we expected to believe?

We go through life being taught several values and general things about life alone. We are all typically prepared for the real world, but the real world throws problems at us at will. Global Warming seems to propose an issue that will never die, so I do not think the debate is over at all. How do we designate what is truth and false, what we can really believe with our heart from things we hear that feel wrong. The more and more people that discuss a certain topic the more confusing it can get. When you look at the both extremes we were told about, its depressing to accept that there is no happy median. On one hand in 50-100 years the world will blow up, and then again we could just have the planet flourish unlike we have ever seen. How does this happen? People will always disagree on almost everything, its hard to find someone that can agree with the way you think. But if Gore had scientists proving Global Warming, how can other scientists disagree? I understand that scientist always try to explore every obstacle to be as close to accurate as they can be, but where does the line fall? I guess this may just sound confusing because I am confused. It's almost as if the government does not want you to fully understand what is going on.