All animals are pre-programmed to breed and to do so at a rate which exceeds the one to one ratio. This is Nature's way of sustaining and expanding a species. The Human species is no exception. However with the other species there are inbuilt controls which usually ensure that they do not expand beyong the capacity of the environment to sustain them. These controls consist of preditors and disease. The development of modern technology means that these controls are effectively removed from the human species which can now multiply unchecked. However the World's resources are limited and human exploitation of these is now nearing its limit.
This situation has been long forecaste, in 1969, U Thant, the Secretary of the United Nations wrote "I do not wish to be overdramatic......the Members of the United Nations have perhaps ten years left .......to defuse the population explosion. In 1972 "The Limits To Growth" , a report for the Club of Rome (an international group of concerned individuals) was published which stressed the problems of population growth and the World's limited resources. You don't need to study masses of figuers with regard to World population to realise that these predictions are now comming true.
For example consider the situation with oil supplies. Oil is not just an essential fuel, it is also the mainstay of the modern chemical industry. Without oil modern civilisation would be in great difficulty yet the oil supplies are strictly limited. Not all those many years ago oil was plentiful, simply bore a hole in the ground in the right location and out it came. Now to meet the World's demand the sea bed, in the most inaccessible under the sea places has to be drilled and what will happen when those supplies run out? Much the same applies to natural gas and some minerals. We can go on a bit longer like this but not very much longer.
It is not just resources but also land is becomming in short supply. 60 years ago some countries were still seeking immigrants. Australia and New Zealand were even subsidising passages for immigrants from the UK. Now every country is closing its doors to immigrants and in effect saying we don't want you, we are full up.
We now learn of vast numbers of people being the victims of famine. Variouse excuses for this are put forward, such as drought, conflict etc but these are themselves indicaters that the World is over crowded. People are forced, through lack of space, to live in hostile and unsuportive lands and there is fighting over viable lands. The Palestine - Israel conflict is one example.