If we want to falsify, we should ask questions like: Was there a time in the past when the atmosphere contained even more CO2 than it did now? What was the temp and did life survive?

What evidence or experiment would convince you the theory is false? Or is that impossible?

Do you believe that question isn't already asked and answered? Just going off the top of my head, I understand historical considerations to be a routine observation as part of your typical course or even presentation on the history of climate change. If you believe this counts, then your answer to your own question about the falsifiability of climate change is yes.

I also don't think that's the only kind of example - I think the routine things talked about on a day to day basis, including year by year and decade by decade temperature predictions would qualify, and these data are quite frequently discussed and quite visible.

I also also don't think the distinction between "evidence in favor" and "attempts to falsify" makes a whole lot of sense. These are two different sides of the same coin, and evidence in favor of something is the same as surviving a test of falsifiability.