Population growth is the result of the plunging death rate and increasing life expectancy worldwide. The growth in human population has been more than met by increases in the production of food and other resources, including energy. Famine in the 20th century is a political rather than an ecological phenomenon. We are not running out of resources, and real prices of raw materials are lower than ever before. Only the price of labor consistently rises.
People are net resource producers.
Countries are not poor because their populations are growing. The England, United States, Hong Kong, and others became rich during unprecedented growth in population. The most densely populated nations are among the richest. What the poor nations suffer from is not too much population but too much government. If the developing world evolves into a liberal market order, it will find that it can have both reproductive freedom and prosperity.