It seems really stupid to write much about this topic. Mainly because there is only one answer to this.
Yes, yes humanity is its own biggest threat.
I mean what more do you need to say about it?
More humans are probably killed by other humans, human inventions or by human made problems then anything else.
A Tiger isn’t a threat to humanity until a human goes near it, a Earthquake might kill many and destroy much but it doesn’t threaten the entire human population of the planet.
We march into a future terrified that AIs are going to rise up and take over and kill us all yet we continue to make more and more life like AIs because we want too. I’m not one of these people terrified of it but if you truly were scared that AI were going to take over then why continue to create them with more and more intelligence and new ways of trying to make them think for themselves?
If the AI do rise and do take over who created them?
Who is truly at fault. The AI who were created by humans or the humans who created the AI?
It is the same with something VERY real like Climate Change and the way that the Earth is slowly dying.
WE are doing that. WE could stop it but because humanity as a whole has created this world where these things the destroy are planet is a daily thing we don’t even think about WE don’t do anything. If the world crumbles it won’t be Climate Change’s fault that humanity stopped existing it’ll be ours for ruining the planet we were given in the first place.
There is nothing that could threaten the entirety of humanity the way that humanity itself threatens humanity.