Consider a situation when without any effort/intervention into the process consequences are predefined to be bad. How do you call such a
If you want to show the worst that can happen in a specific (non-intervention) scenario, you might use worst-case scenario.
That is the scenario that describes what would happen if everything that can go wrong, will go wrong - but that is not always bad. On the contrary, the worst-case scenario is often a good baseline when calculating risks.
When currently the system crashes on start-up, and there are questions about the risk of implementing a quick bug-fix for it, the worst-case scenario is that the fix will cause a crash - since that is is same situation as the current one, the risks may be very acceptable.
If you just want to indicate that currently (assuming no intervention), things will go sour, I think you can present a negative prognosis.
A negative prognosis gives a very strong indication that things look bleak. Things will go badly, and a description of that in the form of a negative prognosis is a great way to introduce a solution that will avert those negative events from actually happening :)