Rick Perry, the head of the US Department of Energy, was asked if he thinks CO2 is the primary cause of climate change. His response was, "No, most likely the primary control knob is the ocean waters and this environment that we live in."
I have a followup question, "What's causing the ocean water and this environment that we live in to heat up?" Earth-spoiler alert: it is absolutely CO2.
Also, "this environment that we live in" is typically called the atmosphere. So, essentially, when asked "what's causing the world to heat up?" Rick Perry responds with "the world." Nice and simple. I once asked my two year old what he liked best about bananas, and he said, "bananas." So, I guess he could also head up the department in charge of all the US nukes.