It is a hypothesis with mechanism, evidence, and data support.
And it is the only hypothesis so far that has mechanism, evidence, and data support.
What do you mean by "at best" ? At best it's a confirmed event. At minimum it's a likelihod with no plausible alternative yet advanced.
As I said....there seems to be an issue with seperating the two......global warming and man made global warming....
Global Warming is a confirmed event......but the connection between global warming and human pollution is at best.....a hypothesis.
No ammount of current evidence you throw at me nor anyone else could be considered anywhere near the realm of valid unless it involves knowing the cycle of the earth in all its history, which it doesnt.
so yes....at best the global warming caused by human pollution idea is at best a hypothesis.