[TeMPOraL]

"Undesirable" and "come at the cost of a lot of human life" is technically correct, but is also a pretty sterile description, that doesn't communicate the full picture.

The worst-case scenario is a collapse of civilization, which - with or without wars - means mass starvation (if you live in a large city, you'll die in the first week). Your grandchildren - or more likely, someone else's grandchildren - will be living in Mad Max hellscape, desperately trying to stave off reverting to pre-industrial levels of life and technology.

(And with all the easily accessible energy sources already mined out and gone, I suspect the next industrial revolution won't be possible for many, many millennia.)