Does anyone still believe that climate change and global warming are not real threats to our world?

I'm pretty sure you're aware that that's a preposterous way of framing the problem. Gas, meat, and electricity still need to come from somewhere, don't they? 

I wish I could tell you they just bring them over from a beautiful land where resources are constantly renewed and no harm is ever done. Y'know, without the need for drilling into the ocean floor, fracking, deforestation - that sort of thing.

Those prehistoric firefighters and wildland managers must not have been very good at their jobs... That's not exactly evidence we're not affecting the planet with our current actions.

I know we've discussed this before, but do you not think we're damaging Earth and overusing its resources? (Whatever we agree or disagree the consequences might be. You may call this unrelated to wildfires, yet it's still part of the same issue: how will we keep existing?)

That is the point there were no humans, and yet there was still fires. That is the climate in CA, they burn. They have tree seeds that simply will NOT open until they are heated to a high temp from a fire.  CA does not have fires and/or drought because of human actions...they have fires because that is the climate.  
How do we exist? We adapt to the climate as nature changes it. 

You kind of dodged the question there. Besides, the point about wildfires was that we have people in various professions employed to prevent and stop wildfires. It's a moot point to talk in those terms about their severity in prehistorical times. After all, there used to be more wilderness to burn.

I wonder if there are younger conservatives who are more concerned about climate change than most (or, frankly, any) older conservatives appear to be. Naturally, it's the new generations that will bear the brunt of the changes, no matter what we claim is responsible for them, when you or I may no longer be around. Someone, someday, might look at sentences like your closing one and think it's not unlike holding a person at gunpoint, saying "don't worry: I'll do what I want, and you just adapt."

We cannot control the sun....we will have to adapt as the climate changes.  If you want to consider the sun as holding a gun at humans that is fine. 

If that were what I'm saying (which you know I was not), and you think that's fine, then could we agree to reconsider what we're doing to the planet, or would you still find that it doesn't matter what we burn/exploit/chop down?

I don't think anyone should exploit the earth.  I also do not think people driving cars or having ac etc does enough to change anything. 

The reason I ask these questions is because I have hope we can find some common ground. You're right in that we need to adapt - so why leave it only to future generations? 

Something else I'd venture to say we can agree on is that the cars you and I drive, or the AC we may use, don't make much of a difference (although any need for resources, and any effects of their consumption, when magnified by more than 7 billion people, might); but what we should be doing is hold accountable those (corporations, people, politicians) who destroy and pollute the most.

For all the talk about it, I still don't think that's really happening. And, politics aside, shouldn't regular people be able to agree on demanding more accountability from those with far great power? Or have we just been letting them divide us?

We can agree those who pollute purposely should be held accountable.  

I think that if we don't do something about it - and it may already be too late - we will not have a habitable planet.  

Do not believe.... or more to the point, for some, refuse to believe.

Some do so out of genuine inability to understand the matter; including the crucial difference between purely natural processes and ones altered by human activities. (Did they ever learn science at school.... even if they were taught it?)

Others for political or economic reasons: whether producers or users, they don't their world to change, for what it gives them.

Others still, possibly from fear. They know it is happening regardless of cause, but find comfort in trying to deny it rather like the head-in-the-sand myth of the ostrich.

Warnings of human-made climate-change first surfaced more than a hundred years ago, when coal was almost the universal fuel for power generation, transport and (especially home) heating. Really, humanity should have started to act then, or at least over 50 years ago; but hindsight is a wonderful thing.

It didn't act because firstly the projected danger times based on coal consumption at the time, would have been much later this Century so seemed too far away to worry about; and secondly, through a touching faith in being able to solve everything under the "Taming Nature" (by science and engineering) myth.