Well, if we lower the bar to "Would something like WW2 happen again?" then I'm not comfortable betting against it. After all, humanity has already managed to do that on its own without any help from the climate!
You can safely bet agains any large scale war like WW2. We no longer have the money or resources for that. We can't build hundreds of thousands of airplanes, tanks, ships, guns, etc. This doesn't include nukes. We have lots of those. But any nuke war will be very very short, over in a day, not like WW2.
