It's hard to understand how anyone can deny the greenhouse effect. We've known about the greenhouse effect since the early 1800s and by 1896 Svante Arrhenius was warning of a relationship between the use of fossil fuels and its effect on the environment.
And, of course, anyone who has gotten into a car on a hot day will have experienced the greenhouse effect firsthand.
The interior of a closed car is a LOT hotter than the outside temperature. And the reason why it is so much hotter is the greenhouse effect: in the car's case, all the glass; in Earth's case, because of greenhouse gases in the atmosphere, you know CO2, methane...
You might ask why isn't it the same temperature as the outside air? It's a matter of whether heat can get in, and out; glass allows the light of the sun in, where it heats the interior of the car, but neither glass nor the roof of the car does a good job letting heat escape. Similarly, the greenhouse gases in our planet's atmosphere allow sunlight down to the surface but act as a blanket to the heat generated when Earth absorbs sunlight.
Our environment is, of course, bigger than a car - and the sun doesn't uniformly heat the atmosphere because the poles get less sunlight, the tropical regions get more sunlight, there is land and there is ocean which all interact differently with the environment, for instance hurricanes only occur in certain places, monsoons in others... However, we do know that the same global effect applies: the more carbon and other greenhouse gases, the greater the impact of the greenhouse effect -- the global warming and climate change that we see in our environment. Heck - plastic trash is being found at the North Pole - it'd be disingenuous to think the exhaust from all the fossil fuels we are using (which, unlike the the trash, we often don't particularly bother to either curb or collect) isn't also impacting the poles.
But here's the thing: I am a data scientist, and I know enough of the "fuzziness" of data sets and assumptions in modeling them to be dubious about the accuracy of specific predictions from any one particular model generated by environmental scientists -- but what I do know is this: we have no where else to go.
Let that sink in.
We have no where else to go.
There are no other planets we can move to if we fuck this planet up. We don't have the technology to get there, or even know if we can survive there. We can't live on Mars like we live on earth. There is only a very small band of temperatures that humans can survive in comfortably, so if you think that we are somehow not to blame for what is going on in our environment, ie the sun is causing it or whatever, then we should be doing all in our power to reverse the effects of greenhouse gases; because we do know that greenhouse gases do affect the environment.
So if the climate scientists are right we are in a lot of trouble. Sure, in some sense we won't be dooming our planet per se; Earth's biosphere will likely survive in some form, and the environment will likely recover - but we humans, and certainly civilization as we know it, mightn't. Perhaps rich people think they can hide in underground shelters with air purifiers - I don't know - but I doubt there is room for all the climate science deniers to survive in those shelters and it's unlikely the rich will let you live there with them. And believe it or not - having a lot of money will be no fun if we aren't there too. (What would you buy, if there's no one to buy from, and nothing to sell?)
And if the climate scientists are wrong, but we listen to them anyway? Well, we get a clean planet, a clean environment - to me there is no downside. ("Green energy" doesn't mean ending life as we know it or crashing the economy - it just means shifting resources from e.g. oil and coal to, say, solar, wind, hydro. And it has already been working around the globe; California's economy, for instance, hasn't suffered from "going green"!) Yes -- in the short term -- perhaps some rich people won't be able to make quite as much money if they actually have to clean up after themselves, but we'll be there for them to help them being richer than us. (And in the end, rich folks can just shift their wealth into the new energy anyway, frankly.)
So if you are a climate science denier, then you better be being paid to be one (and feel perfectly OK about the people who believe you, and those who don't, being left out in the cold if civilization finds its back against the wall) because those who are making their money are doing so at your expense. They don't care if you die because of them.