I don't think that's clear at all. There's damage being done, and ameliorating or avoiding that is sensible, but "destroying" is quite an exaggeration.
The question is when you consider planet Earth "destroyed". Most likely it will remain blue and keep its atmosphere. Life will continue. It could be "destroyed" in the sense that humans sustainably sabotage their own long-term survival, or the survival of other species.
Short of a nuclear war, I don't think humanity will get close to extinction. But I think we are on a path to lose access to today's cultural knowledge (like microchips, vaccines, aviation). If the population is forced to shrink over the next couple of centuries, wars over fertile ground seem more likely than specialized global supply chains.
I mean you're kind of being a bit silly. I don't think OP is saying we will spontaneously catch on fire and die. I think they are suggesting that vegetation which can only support a certain amount of heat and no water will parish. Also funny enough we can only support a certain amount of heat and no water.
It is pretty apparent that we are going to have water problems in the coming decades. You don't need to be a scientist to put those two together.
I am not saying we can't fix it, I do not hold the same outlook as OP. But we will have problems. Even if you don't believe global warming, there is obvious signs of issues popping up with water, and heat. Mexico, parts of USA, Canada, etc limiting water usage and saying they'll run out if it doesn't rain. That will be a problem.
