[PlanetLotus]

I'm not particularly informed on the subject, just using some basic understanding here:

1. Can't CO2's "strength" as a greenhouse gas be measured directly? That seems like a relatively simple physics problem. My understanding is that the direct effect of CO2's "heat trapping" is easy to quantify. What scientists continue to disagree on is how significant the cascading effect is, but of course we do know there is one. But even the most conservative estimate (no cascade effect) shows that as we add CO2 to the atmosphere, the planet will continue warming to life-altering levels.

2. I don't think I understand this argument as long as the denier will acknowledge that the planet is warming (which is directly measurable). If the planet is indeed warming, this 2nd argument seems to indicate that CO2 levels are cyclical based on the sun's behavior, but that's not what's happening now. Maybe I'm misunderstanding the implied timeframe over which this is supposed to happen...but this, again, seems directly disprovable.

Let me know if I missed the point, but it seems like the whole argument falls apart as soon as you show that CO2 has a significant warming effect, which is something scientists are confident about.