Well, let us assume for a minute that God had died. Implications vary, depending on belief.
If, for example, you are of the opinion that God created us, and watches over us like chicken, then there would definitely be an impact on the moral fibers of many peoples, groups, to even societies.
If, for example, as Isaac Newton postulates, that God created us, and the rules of existence (physics, motion, et cetera) provide the mechanisms to keep our environment as it is, of course with modifications by all living things, but God has walked away, leaving us to our own devices, then the impact will be minimal, if any.
If you believe in the middle of those two, where God created us, but he oversees the laws of existence, then the impact will definitely be felt; maybe not as strong as the first, but definitely more than the second example.
If you believe that God never existed, then God could never die, and therefore, there just would not be an impact.
If you believe there are many different gods, with the supreme God at the top of the food chain, then the death of the supreme God would probably affect more the lower gods themselves, which would ripple slightly down to the humans.
There are many different paths to examine, and I doubt I have brushed even 1% of the possibilities; each one has some type of impact, ranging from none to a lifestyle change.
I do not have a personal opinion or belief, therefore, I cannot put forth what I think the possible implications of having God die in my lifetime.