I do think global warming is real, the question is how much of it is just the natural cycle of our planet and how much of it is the fault of humans? In my opinion it's a combination of both. Our planet is naturally getting hotter at a very slow rate & we are probably speeding it up, the question is how much are we speeding it up? Look at our neighbor Venus... what you see there is basically a massive natural greenhouse effect on such a large scale it's hard for us to comprehend. Extreme carbon dioxide emissions do warm planets, that's a scientific fact. It happened naturally on Venus, and it's happening naturally here, albeit IMO we are speeding it up.
In theory, if we had the resources/technology we could one day deliberately heat up a planet to make it habitable. It's hard to grasp the idea and it seems like some crap from a cheesy sci-fi flick, but in theory it could be possible. Imagine we built a gigantic machine that could emit an unfathomable amount of carbon dioxide. Pretend we took all the carbon dioxide that has ever been put into the air from humans... from every factory, every car, EVERYTHING since the beginning of human existence on earth... if this theoretical machine could emit a thousand times that amount of carbon dioxide on a daily basis over a long period of time then you can literally warm up a planet. You could take an uninhabitable planet that's too cold with too thin of an atmosphere and intentionally warm it up/create a dense atmosphere that could make it habitable as far as temperature is concerned. Of course, we'd have to find a way to get oxygen into the atmosphere if we were to settle there "outdoors," otherwise we'd still have to live in a pressurized/oxygen filled vessel.
Again, this is all theoretical and we're thousands of years away from even coming close to trying some shit like this but the laws of physics agree with the premise. It is absolutely possible to deliberately heat up a planet.
The bottom line is the earth is slowly warming up naturally and we're slightly speeding the process up... but we could be speeding it up a lot faster than we realize which is a scary thought so we need to take the idea of global warming very seriously IMO.
Disclaimer: I'm not a scientist, I'm just a huge stoner/nerd who went to space camp as a kid and after I track all my action for the night I watch/read tons of shows/books about science & space. I'm sure somewhere in this post I said something not entirely accurate but for the most part I think I hit the nail on the head.