If current trends continue, then the Earth's climate will undergo some pretty dramatic changes, even in our lifetimes. But most scientists now agree there is a waterfall ahead of us. No, it's you who is to blame. Good question, but let me be picky for a moment. In Spanish, La refers to female, and El to male.
Scientists have good weather records available from the past century, and then some.
Well, maybe, unless the basketball team had just decided it needed a cappuccino break. Scientists avoid trying to draw large conclusions from small amounts of data. In other cases, no matter how much data we have, the best we can ever do is say there are several possible outcomes, and assign rough probabilities to them. That's part of the nature of some inherently unpredictable systems - the best we can ever do is talk in generalities. I don't want to get into it too much here, but the world is filled with such chaotic systems, where making tiny changes in the starting conditions can lead to huge and unpredictable differences in the outcome.