There are plenty of things that would change my stance on global worming. But, like most long studied subject's there is a
lot of evidence to back up global worming. Everything from samples of arctic ice from thousands of years ago, to plant samples, weather models, and satellite data. But, the two basic factors that would change my mind are:
#1) A well defined mechanism that limits the impact green house gasses on temperature and weather.
#2) An accurate, global, and long term temperature measurement that strongly links global temperature to some other factor and shows little correlation with CO2. Which is more accurate than all the other data we have collected to this point.
I studied the physics behind global climate models and there are other factors that impact temperature, but most of them are short term factors and CO2 has a stable long term impact. At the basic level CO2 changes how much energy leaks to space though the atmospheric absorption gaps in EM spectrum. At temperature rise that changes some but 280 kelvin vs. 282 kelvin is minor etc.
Local areas can experience dramatic shifts in weather but as a global system energy in must equal energy out +/= extremely tiny fractions which are stored / released energy. etc.
PS: I am willing to change my stance with new information which is why this is not a religious stance. But, without such information there is little reason to change my stance.
Edit: The reason I called his statement as a religious argument is it equated the process where I gathered data to a religious viewpoint. However, if your staying that you feel global worming does not exist as a religious stance, I will stop talking, because there is little reason to present information to someone who does not care about it.