One of the most striking claims of the Great Global Warming Swindle was that in the historic climate record, the temperature rise preceded the rise in CO2 by approximately 800 years. On the face of it, this is pretty good evidence that temperature is driving CO2 rises rather than the other way round, which is exactly what the heretics claimed in the programme. As far as I can see, its existence is largely undisputed (although I have been pointed to one dissenter).
The orthodox response to this is that CO2 is a feedback mechanism. Something causes CO2 to rise. Because CO2 is a greenhouse gas, it warms the earth, which raises CO2 levels, which warms the earth further and so on. My initial objection to this was that the cycle should feed back exponentially. Apparently the answer to this is that the supply of CO2 is l finite, so when it runs out the feedback loop is broken. But nobody actually knows what causes the rise in CO2 anyway, so we're in the dark as to the details.
From my perspective, this all looks somewhat dodgy. Both methods rely on an initial warming of the earth to produce CO2 (by a mechanism which isn't understood). The heretical case is that that's the end of the story. Warming produces CO2. (I assume they argue that any warming from the CO2 is small because, relative to water vapour, the contribution of CO2 to the greenhouse effect is small). The orthodox case, however, imposes a CO2 feedback on the initial process. This, however, requires another process to prevent the feedback spiralling out of control - one which is inextricably mixed up with whatever started the whole cycle off in the first place.
Which seems, I must say, a tad unconvincing. Certainly not something I'd like to rely on before I took drastic action. The orthodox case seems to fall foul of Occam's razor.
I must say, I feel certain there must be more to it than this, so if anyone can enlighten me, I'm always keen to hear. Why is the the heretical case not considered more plausible? What is the flaw in their case which requires imposition of a feedback loop?
As always, I should point out that I'm an interested amateur rather than a professional scientist, and there is a possibility I've got either camp's arguments (and probably both) completely wrong.