So, ...the fact that people are choosing sides and arguing about its significance --somehow proves that it is insignificant. I don't follow that logic.

..but I do agree it's hard to prove either way, and it's pretty much impossible to know exactly what it's effect will be. But drastic climate changes may cause large scale migrations of billions of people --way sooner than we are ready for. That won't be fun. (Nor would an asteroid on my head be very much fun)