(CNN) Although climate change is thought of as simply a political football, it has been a heated topic among meteorologists for years. I, for one, have changed my conclusion over time on whether humans are responsible for the increased heat content of the Earth.

I write this article not to change your mind about global warming; I simply want to show you why I changed mine.

Early in my scientific studies at Nebraska, most believed that humans could never pollute this massive globe enough to make a measurable difference.

As a student, I learned to never exclude any possibility until ultimately that possibility is proven false. It was called skepticism, not denial, and skepticism is a key foundation of the scientific process. In the '80s and '90s there seemed to be many other potential causes of climate change, not only humans.

Volcanoes, solar fluctuations, city heat-islands, concrete production and yes, even the cattle population. The list went on and on and seemed endless. I wondered if all these potential causes were given adequate consideration?