Well, I wanted to show you guys a little calculation on a rather big question.
What do you think how long there will be humans on this planet left? How long will man survive?
The big deal about the calculation is that there is no need of any knowledge of the actual situation of mankind and its planet. It's just some piece of math...
Here it goes: Imagine all humans that ever lived and is going to live, set up in a row by chronological order. Just think as if you knew how long this row was (You don't, since you don't know how many humans will live in the future). You are somewhere in this row. Now, if you don't know where you are, there is a 50% chance that you are in the first half of the row (of course, since the half of the row is 50% of its length and you don't have any information that would favor some position for yourself). For you being in the second half, there is a 50% chance, too. You can extend this: There is a 5% chance that you are in the first 1/20th of the row.
I read that there lived like 100 billons of people on the earth yet.
Now, with regards to the 50%, we can say, there is a 50% chance for humankind to survive the birth of the next 100 billon people. In fact, there is a 50% chance that humankind is NOT going to make it for another 100 billon humans.
If you think about how fast population is growing, you can either think
a) the humankind will be wiped out in the next few hundred years
b) in a few hundred years there will be only few people and not anymore billons of them living...
This calculation is not really useful and somehow inaccurate. However, it is fun to take a look at the question from this point of view, because you don't need to care about actual problems we are facing.
A less nerdy post later this day or tomorrow is incoming, hang on and don't care if you don't get what I'm saying ;)