Scientists at the Swiss-based CERN recently concluded experiments that seem to show the Sun and its changing magnetic field affect cloud formation in the Earth's atmosphere. The whole story gets a little ugly, with CERN management stalling and stifling scientists wanting to explore activity that might possibly discredit global-warming models and theories. (Read about here.)
As a college student, I did a bit of mathematical modeling of various systems and studied the models from the Club of Rome (Limits to Growth, anyone?) One thing I learned is that if you don't know about a causal relationship between two or more variables in your model , or you don't even know a variable plays an important role, you won't be including them in your model. I also learned you have to validate your model to have any confidence in it. That's why I largely ignore predictions coming from climate “experts” based on their own, often proprietary models. And when they claim to have lost the data that went into creating the model, I suspect shenanigans.
So are you convinced global warming is a threat? Or is it just the doomsday prediction du jour?