Not in a Sixth Sense kind of way,

but in an 'inexplicable mass resurrection' kind of way.

Not in a 'Walking Dead' kind of way,

but in a "Holy cow Grandma's back!" kind of way.

While this might sound like a great opportunity to catch up with lost loved ones,

and to meet some of your heroes...

it would actually be horrible.

This is 'What If,'

and here's what would happen if every dead person came back to life.

there are still way more dead people.

If we go back about 200,000 years ago, when modern humans began to evolve,

and counted all the humans who have been born between then and now,

well, you'd be looking at a crowd of about 108 billion people.

Now imagine all of those people alive right now.

Some scientists believe that our planet can support a maximum 10 billion people.

And according to UN projections, we'll reach that number by the year 2100.

Now, still scary, but at least that gives us some time

to come up with solutions for overpopulation on Earth.

So suppose you're thinking about it over a cup of coffee one day,

and you look up, and you see someone you haven't seen in a long time...

because they're dead.

But they're not anymore!

In fact, everyone who's ever lived on Earth is miraculously brought back to life!

Only it's not a miracle, it's a crisis.

A food crisis.

Space isn't even the main problem, since,

throughout all of human history, until about the last few decades,

most humans lived in rural areas;

and that's probably where most of the resurrected would return to.

Ironically, despite having enough land to fit everyone,

we wouldn't have enough available farmland to feed everyone!

and that was to feed what is now only 7% of the total population.

There's simply no way we'd be able to feed 100 billion people.

Under these constraints, 90% of the world's population

would easily die of starvation within two months.

And that's not even including deaths

that would arise from the world war ensuing over resources,

which, honestly, would be a really unfair fight.

Relatively quickly, the world population

would stabilize at a reasonable, if not a quite cramped, capacity.

And while it would all be settled in a few months,

those who survived the shock and awe would still be wondering,

"what the heck just happened?"

While it's a totally impossible scenario, it does give you something to think about.

The UN claims that in recent years,

families around the world have been getting smaller,

and fertility rates are decreasing.

But is it too little, too late?

Catch up on other big questions next time on 'What If.'