I simply can't spare 6 years to become an expert.
Good grief, man. You can at least acknowledge that some sort of evidence is required to draw a scientific conclusion.
For example, Vostok data shows that rising temperatures preceded rising carbon dioxide levels. Likewise, falling temperatures preceded declines in carbon dioxide levels. This is data that even the UN published. It is solid scientific evidence showing that there have been six temperature cycles over the last 600,000 years - long before humans started purchasing automobiles.
Evidence, evidence, evidence. Ask yourself "Do I have any evidence?" Because it doesn't even take a fifth grader to figure that one out.