I think it might be considered evidence, but CO2 levels vary quite a bit over time. Picture what would happen if we measured atmospheric bass on a planet over a few hundred years and saw that kind of swing in CO2.
Decidable radio signals on the other hand are far less ambiguous. I just can’t think of much that would be both detectable and a smoking gun.
Decidable radio signals on the other hand are far less ambiguous. I just can’t think of much that would be both detectable and a smoking gun.