Your opinion, not a fact.
In your perspective what you are really considering is not a world without God but a world started by a God who quite generously gave a set of morals but where that God suddenly disappeared.
For a Christian, God did not "suddenly disappear" but remains with the world.
You are also asking two questions. The first is 'where did the morals we have today originate' and the second is 'how would we act if we did not believe in retribution from on high'. You will note that the second question does not depend on the true origin of the set of morals.
I don't thing questions are being asked but claims are being made. Related to your questions the claims are:
If you want to answer the first question you cannot simply assume God then ponder a 'what if' - you need to look to both assumptions; that the current moral set has two potential origins, one with God and one without, and then compare their explanations.
Perhaps you cannot, but I certainly can and do. You also make a mistake if you think I assume God exists. It is a deeply reasoned belief.
To answer the second question you need to examine a number of cultures (not an individual), current or historical, that does not have a retributive God figure.
I have no such obligation.
"For a Christian, God did not "suddenly disappear" but remains with the world."
I was addressing your argument not your belief.
You made the following statement:
From my perspective, in a world without God, there is no right and wrong, only actions and consequences.
That statement, as an argument, makes the assumption that God is the cause of the morals we have and if God disappeared those morals would change or become completely arbitrary. You are *not* considering a scenario where God never existed.
Now it may be that you had no intention of considering a 'Godless' world as an argument and were just throwing out your opinion that if the 'belief' in a God disappeared then humanity would have no reason to follow 'Christian principles'. If that is the case then I grant you your opinion as you granted mine.