11.2 billion?

The UN has released a revised projection of global population and they now project that there will be 11.2 billion humans alive in 2100. They expect the most rapid growth in the poorest regions:

Population growth remains especially high in the group of 48 countries designated by the United
Nations as the least developed countries (LDCs), of which 27 are in Africa. Although the growth rate of the LDCs is projected to slow from its current 2.4 per cent annually, the population of this group is projected to double in size from 954 million inhabitants in 2015 to 1.9 billion in 2050 and further increase to 3.2 billion in 2100. Between 2015 and 2100, the populations of 33 countries, most of them LDCs, have a high probability of at least tripling. Among them, the populations of Angola, Burundi, Democratic Republic of Congo, Malawi, Mali, Niger, Somalia, Uganda, United Republic of Tanzania and Zambia are projected to increase at least five-fold by 2100. The concentration of population growth in the poorest
countries will make it harder for those governments to eradicate poverty and inequality, combat hunger and malnutrition, expand education enrolment and health systems, improve the provision of basic services and implement other elements of a sustainable development agenda to ensure that no-one is left behind.

I've got news for you: if there's no way to feed those people, they won't be there after all. And I've got more news for you. The global population is concentrated in coastal areas and those people are going to have to move. At the same time, the hottest regions will become uninhabitable and the distribution of arable land and climate appropriate for particular crops will shift. There will be serious water shortages in many places. The result will be civil conflict, famines, and likely uncontrollable epidemics. So no, there won't be 11.2 billion people. There can't be.

The question is how we get to the lower number that is actually going to happen. The options are fewer babies, or more premature deaths. That's it. Take your pick.