Overpopulation: environmental damage.

The rapid growth of the world population, now of 7 billion people, and the struggle of the poorest peoples in underdeveloped or developing countries to survive are causing enormous damage to the environment. 
For instance, several countries are burning or cutting down their rainforests merely to get money. 
Furthermore, they are overgrazing grasslands and exploiting croplands in a desperate effort to produce more food. 

What should governments do? 

First of all, the goverments of underdeveloped and developing countries should promote education, especially amongst females, in order to ensure they get married and start having children later. Moreover, an educated mother wants to educate her children too, triggering a positive chain reaction. 

I know a system of birth control such as the Chinese one may seem unfair, but if they hadn't done so, how many people would have lived now on the planet, with all the negative consequences? In my opinion, in some regions of the world, where the birth rate is still extremely high, that would be a good solution. 

Another way to lower the number of births is the transition from a pre-industrial society to an industrial, so that the children are no longer seen as a labor force for agriculture, but as individuals to maintain for a larger number of years. 

If the world population exceeded 12 billion people the consequences, not only for the environment, would be devastating, so it is vital that governments adopt strong policies in this regard as soon as possible.