Paris accord hasn't been around for long enough to see if it'll actually produce meaningful results. Kyoto Protocol was around longer, and would you call it a success? If it was, then why have a Paris accord? The examples you have listed are things where the benefits are pretty immediate, not a couple of generations away.

To get to the level of co-operation needed, a significant investment needs to made in educating people of all mindsets, about the benefits of this co-operation. That itself is going to take a couple of generations.

I didn't say it was easy, but dismissing it as impossible doesn't do anything to accelerate that process because it drains people's morale at the beginning of the task.

It makes more sense if you ask: "what economic interest group would be significantly impacted if consensus was achieved?"

Basically, follow the money.