Approximately 90% (9/10ths) of our Universe is dark matter and dark energy. That means that we can see, manipulate and partially understand 10% (1/10th) of our Universe. Until very recently we had no idea that 90% existed.

Why don't we understand it? We don't need to. And if that is just coming into our view, what else is over the horizon? What is behind dark matter and energy? We don't know. What else don't we know? Obviously we have no idea. Can we figure it all out eventually? What indication is there for that? None. We bounce from one reality to the next to the next. Newton to Einstein to quantum physics to dark matter to what?

The reality is that without some changes in nature (no chance) Mankind won't make it another 300 years, making us one of the least successful species of which we're aware. The stresses on our societies coupled with our technological abilities will lead to our species committing suicide. How many others have lasted less than 100,000 years?

An alternative is if one country decides that the crises are such that corrective measures must be imposed on those who won't work for the common good and occupies those countries, forcing compliance. If China and India decided to do that they have the manpower. No one else does. The US launching nukes would just make it easier for them, as there would be fewer Americans to control when it was done.

I believe there is a limit to what we can know, there is a limit to what information is available to us, we are in a bubble (our universe) and cannot know what is going on in other bubbles. And as a measure of our arrogance, consider dark matter and dark energy. And what is behind those phenomena.