Roger69  I would like to share my views on Rebirth-

Concept of Rebirth is accepted in Hindu literature. You have to take birth/form again and again unless you reach to Moksha level. Many religions don't believe in rebirth concept. Their view is after death men (including women) goes to heaven or hell according to their deeds. 
In Geeta, when Arjuna asked Krishna how he can kill his own relatives. Krishna replied that You can't kill anyone. because Atma is not destructible. It can't be killed, cut, burnt etc. So, no one can get killed only changes forms. (Mind you, this is purest knowledge, to understand Truth. Not for taking legal stand after killing someone)
In every knowledge book it is emphasized that 'You are not body, you are Atma' By this principle, you are here when the world came into existence and you will be here till the world is existing. You will only change forms. 
This makes concept of swarg and Narak as imaginary concepts prepared for genral public so they can do good things in the greed to go to heaven/ Swarga.
The concept of Atma is same as Energy. As energy can't be destroyed, it can transformed from one form to another. Atma is energy. 
When a person realize at his own (not by other's experience) that everyone is Atma or consciousness and part of Universal Consciousness or paramatma. He is said to attained Enlightenment. Then he can say that I am part of Parmatma -Amah Bramhasmi. At this stage, his energy becomes part of Universal consciousness and he is freed or attained Moksha.
And a possible explanation of rebirth in terms of present population blast..... has following points..... the total number of soul at a given time is constant in total number of living forms..... so as Humans are increasing they are doing so at the expense of souls in other forms..... and that is why we are facing a mass extinction..... 

a_decent_1 

Agreed.
Question arises when a Disaster takes place.
Take the example of 9/11 Terrorist attack. A LOT of people died. Did they all have it in their Karma to die at the Same time, Same Place and Same Misery..? Too co-incidental to be true. When there was TSunami, did each one of them deserve to die..?

I believe that Karma is not only effected by what you do...... in a chaotic system..... state of each component is effected by all other components states.... even if they are not in any contact..... any student of chemistry will tell you when precipitation starts many particles not having the precipitating tendency in those conditions also precipitate due to this effect....... take death as precipitation.... its like death around them is attractive ... so there is a domino effect......