Wrong question. There is no "who". Science does not answer the question "why is the sky blue? It answers the question "how is it that our eyes / brains perceive the sky to be blue (this particular wavelength).

Asking why presupposes a creator. "Why does a rose have thorns?" "To symbolize the hardships and vicissitudes of life."

A scientist will not ask that question. He will pose a question and then test his thesis. AND, if the thesis cannot be falsified then ... it's not science.

My grave problems with global warming reporting is that it does not include how the thesis can be falsified.