This is a very interesting topic and some theorists claim over-population as one of the reasons for poverty and other problems of the world. And as usual, there is always a huge blame on countries with huge population, especially China and India. Let us try to look into this debate. I happened to read a book ‘The republic of Hunger’ by Utsa Patnaik and the themes used there are used to analyze the situation. (I also would like to state that in terms of population density (number of people per square km), there are more than 50 countries above India and China. https://www.indexmundi.com/g/r.aspx?v=21000)
In the introduction to the book, Utsa Patnaik uses two terms nominal population and real/effective population. I will try to explain the two terms with an example. We have 3 countries namely A, B and C which have populations of 5 million, 5 million and 1 million respectively. I am using a special parameter called E (only for example) which is a number denoting the demand on the resources made by a person. They are 1, 2, 10 respectively for A, B and C. In our normal understanding, we would say countries A and B are much highly populated than C. So A and B have nominal population much higher than country C. Real Population = Nominal Population * E. The real population is 5million, 10 million and 10 million respectively for countries A, B and C. The real population of C is much higher than A, though the nominal population of C was lower than A.
A population of 1 million (country C) exerted double the pressure on resources than country C which has a population of 5 million. This is a significant factor which most of the analysis by developed countries ignore. USA accounts for about 20% of the world Oil usage when it just have less than 5% of the world population. The growth of developing countries (especially China, India) gives a nightmare to the developed countries as their real population too will increase (E will increase) and the people of the developed countries are not ready to shed even a little bit of their privileges (Reduced E).