While the overwhelming majority of the scientific community accepts that global warming is a thing caused by humans, a small but very vocal minority is adamant that it is not.
We could go round and round and round in pointing to all the evidence in a bid to persuade those 24 per cent of Brits or 32 per cent of Americans who disagree with science, or, it turns out, we could turn to former Mr Universe and governor of California, Arnold Schwarzenegger.
Arnie, who has been in Paris this week for the all-important climate discussions at COP21, took to Facebook to ask some important questions of those who doubt climate science or just send abusive four letter words to people who want to clean up the planet.
His post has three key points, the first two of which are:
First - do you believe it is acceptable that 7 million people die every year from pollution? That's more than murders, suicides, and car accidents - combined.
Every day, 19,000 people die from pollution from fossil fuels. Do you accept those deaths? Do you accept that children all over the world have to grow up breathing with inhalers?
Now, my second question: do you believe coal and oil will be the fuels of the future?
Besides the fact that fossil fuels destroy our lungs, everyone agrees that eventually they will run out. What's your plan then?
But then he ends it with this:
I have a final question, and it will take some imagination. There are two doors. Behind Door Number One is a completely sealed room, with a regular, gasoline-fueled car. Behind Door Number Two is an identical, completely sealed room, with an electric car. Both engines are running full blast.
I want you to pick a door to open, and enter the room and shut the door behind you. You have to stay in the room you choose for one hour. You cannot turn off the engine. You do not get a gas mask.
I'm guessing you chose the Door Number Two, with the electric car, right? Door number one is a fatal choice - who would ever want to breathe those fumes?
This is the choice the world is making right now.
Well now, that's pretty hard to argue with...