have you ever been stuck on the side of the road in a broken down vehicle when its -20 outside? yeah it happens and more frequently then you would think. better to be prepared with something proper and not a brown paper bag coffin for my chameleon. although if you live somewhere warm this isnt an issue
No I don't live anywhere like that. I have for several years of my life when I was young, and I can honestly say I would do anything possible to avoid living someplace like that because for me and my lizards, weather like that just plain sucks. LOL. But we do get storms a couple times a year that ends up with a wreck on the highway and travelers stranded for up to several hours.
But- I never said if temps were -20 below use a paper sack alone. I said put the sack in the cooler if it's below freezing out with a chemical heat pack or warm bottle of water. Heat packs last several hours and in a modern cooler so will a warm water bottle.
Every situation is going to be different. If it is a 10 minute drive to the vet and it is freezing out- use a cooler.
If i were you i would go and pickup a small rubbermaid container, line the inside with some styrofoam insulation or a good blanket etc, have a heating pack that doesnt get to hot that you can put on the bottom so the heat radiates up and have a couple things in there he can hang onto during transport.
Congratulations- you've just reinvented the cooler! Available everywhere for a few bucks and no work. And then you've done exactly what I suggested which was to use a chemical heat pack or a water bottle with warm water. Guess my idea wasn't so bad after all.
You can drill a couple holes in the lid so there is adequate ventilation.
Yeah- don't do that in your re-invented cooler or a real cooler. As soon as you do, you destroy the insulating properties of the cooler plus invite fridgid drafts into the thing. A cooler or your re-invented cooler will both have enough air to last a day or more inside. People ship lizards in them all the time without air holes and they are fine. I've even gotten a few really large lizards in years past that were shipped to me this way- several pounds and 4 feet in length plus, and they were fine and had enough air for a trip of over 24 hours. That said- I'm guilty of poking a couple of airholes into the side walls of my shipping containers myself. But seriously for a trip to the vet or across town or even for several hours, no ventilation should be fine.
I'm gonna be doing the exact same thing pretty soon as winter is coming and my cham comes with me most places.
Why would you bring your cham with you "most places"

especially in a place where it is -20 to -40 and cars break down on trips stranding people for several hours very often?
i dont care what anyone thinks anything below 50f is not good for chams, they have no insulation and will instantly be frozen if not taken care of.
Well, not that you care what I think (or what anyone else thinks), but my veileds regularly spend nights outdoors this time of year at temps below 50- if fact I only bring them indoors when temps drop below 40. And contrary to your belief, they don't freeze instantly and actually they don't freeze at all at temps 40-50. This is a veiled we are talking about in this thread right? And the forcast stated was 40s and rainy, not 40 below and blizzard. Don't let facts get in the way of your opinion though.
Anyway this has been tongue in cheek, but I hope that poster isn't the only one who took my paper bag method like that. I've used paper bags taped securely in insulated boxes for shipping lizards for 20 years and have never, not once, had an animal harmed in shipping even when shipped in the middle of winter to areas that were very cold like minnesota in January.