Don't deny science! The evidence for man-made climate change is undeniable. Starting with the fact that CO2 emissions reached a new record high in 2014 (2014 was the warmest year in modern record!). Most of us are aware that CO2 is a greenhouse gas (a gas that contributes to the greenhouse effect by absorbing heat). So, by releasing more CO2, we are warming the planet.
Its called the greenhouse effect. There is an entire episode of Cosmos devoted to it.
I don't really buy the man-made argument. Saying that rising CO2 and temperature proves climate change is a correlation/causation fallacy. There is a chance that such a rise isn't due to CO2, and CO2 is vital for earth life anyways, so I'm pretty skeptical about it. It seems to be an excuse to fear-monger, and is definitely short of a crisis.
What the heck? People, the climate has literally been changing since Earth came into existence! If you look at graphs that depict the past, in context of the climate, you will see HUGE variation in temperatures, much higher and much cooler than today, so no it is mostly natural.
You have to look at the really big picture. The pro AGW alarmist show you only a very small snapshot of time.
The cause itself is overall natural. Even if humans didn't exist, the climate would still change over a long enough period of time. However, humans are the reason that it is accelerating exponentially. This is worse than being the cause, because the attitude of "I didn't cause it, so I can do whatever I want" is that of a child. It's the equivalent of watching an electrical fire spark in your house, but just pouring fuel on it because you didn't start it.