I was thinking about this last night, and what frustrates me about this question is that it’s like the theory of relativity. I know that the two theories of relativity have been largely confirmed through evidence. But if you asked me to come up with a “falsifiable hypothesis statement” I’d be completely at a loss to find one.
That does not, however, mean that no one has found one. In fact I find it absurd to even suggest that the relativity hypothesis has not been tested adequately (edited though I think we would find that physicists who understood the issue well accepted it on relatively scant evidence because they, being deeply familiar with previously unexplained results in their field, found that evidence compelling. Some things predicted by relativity were not confirmed until long after Einstein’s death.)
The law of conservation of mass means we know humans are responsible for increased CO2 concentrations.
The law of conservation of energy, as well as numerous temperature records, means we know that the planet is warming.
Greenhouse gas theory made several predictions, all of which were either proven right or shown to be plausible. Are these the falsifiable hypotheses you’re looking for?
P.S. it’s a fallacy to suppose that a hypothesis is false because it doesn’t make predictions about the future. If it explains all the data, and there are no other theories that explain all the data, it’s probably true. Not that it matters in this case; GHG theory did make predictions about the future.