[asdff]

It won't be extinction level, no, but there will be famines and migrations and collapse of governments and violence. That much is guaranteed.

[midasuni]

And in 1000 years what will the situation be?

[asdff]

The same as its always been. A handful of people on top of some arbitrary social hierarchy in charge of the lions share of available resources. I believe this type of social organization is in our innate behavior like how insects form colonies and fish school.