For me, I draw the line with some basic facts and basic physics. If you disagree with those, I would say that you're in denial, and to have a rational discussion is as likely to have a rational discussion with a Young Earther on geology. This basic fact is that there is anthropogenic increase of CO2 in the atmosphere. We had a lot of CO2 captured in the soil of the earth, and we've put it in the atmosphere. If you want to dispute that, there's no helping you, you are in denial. Second is a basic bit of physics: with increased CO2 there is increased retention of heat -- given all else being equal. This is the greenhouse effect. If you dispute that, I would like to urge you to create a greenhouse and observe. We can fairly accurate estimate what increase in warmth we can expect with increase in CO2 concentration. Again, disregarding all other factors such as heat sinks and many of the things that make climate modelling so difficult. This is a highly idealized physical theory that cannot be blindly applied to climate, yet it establishes one important thing: CO2 is a forcing term in the earth's atmosphere by its ability to capture heat. And we can very exactly compute how much heat it captures, and boy, are we in trouble!
If you accept those two things, it might be worth having a discussion about climate change. We, as humans, have introduced a forcing term in the climate that can be expressed as an additional amount of energy that is retained in the atmoshpere, and we are now trying to establish the actual effects. It is fine to be sceptic about some of the results, but honestly, you should also consider the possibility that some of those models are right. Just dismissing them is not an option, as the idealized model already predicts massive trouble. You would have to explain how this is NOT a problem. Claiming ignorance won't help you here, as you are arguing that many knowledgeable people are basically wrong.
The third breed of denier/sceptic is the 'anti-alarmist'. They hate the discussion about what to do about climate change and are denying the science in order to derail the discussion. A fair person would examine the actual ideas, and propose a weighted argument about the costs of the ideas versus the actual uncertainty in the rate of change we're experiencing. A denier just denies the science.
Finally, there is the bona fide sceptic. Somebody that has read up on the subject, has found some major issues, and is busy keeping his peers (because he is climate scientist by now) honest. Some of them exist (people know them by name), and although many don't agree with them, the are fairly well respected.
So, what type are you: the 'young-earth' equivalent of the denier that cannot understand logic and science, the lazy sceptic that does understand a bit of science but cannot be bothered to actually read up on it, or the political activist that denies the science because he hates his policial adversaries, or a scientist that has some informed sceptical point of view? You seem to be a mix of the first three. A bit more honest than most, but still pretty deluded in your reasoning.
