I believe global warming might be a large scale version of the placebo effect, just not medical.
Definition of the placebo effect:
"a beneficial effect, produced by a placebo drug or treatment, that cannot be attributed to the properties of the placebo itself, and must therefore be due to the patient's belief in that treatment."
Although global warming isn't a drug, or a treatment, it is a belief that something is wrong with the earth and we have to do something about it. I don't believe that there is any such thing as global warming, if there is, it may just be another ice age.
I'm going to keep it simple, Antarctica melts along with the Arctic ice up north, everything floods, everything freezes, BOOM! Ice age! It's a logical reason this may be happening, there may be more theories but this is mine. After the second ice age begins a long time passes, everything repeats. Basically an ice age cycle. Plus what can us humans do to stop it. It's already in progress (if global warming is a thing that is currently happening).
Just let nature take its course.