Another source says similar, i.e., world population will peak to less than 10 billion by the 2060s, and the main driver will be rapid industrialization in the developing world, leading to, among other things, more education for women and options for artificial contraception (which was raised by the
Lancet article). That means that the main cause of lower birth rates is greater prosperity.
The problem is that the amount of energy to make that industrialization possible is many times more than what's available or attainable:
https://www.anthropocenemagazine.org/howmuchenergy/That is, the world population current uses around 20 TW, and that's for a population where 71 pct of workers earn less than $10 daily:
https://money.cnn.com/2015/07/08/news/economy/global-low-income/Clearly, better education plus not just availability of contraception but many other options (including higher-paying occupations as a result of better education) are based on industrialization, which in turn requires lots of energy to extract and process all sorts of goods for basic needs and wants and infrastructure development.
In order to attain that level of industrialization, the current population will need around 50 TW. If that population increases to around 9-10 billion due to momentum, around 90 TW will be needed for the additional number of people. To mitigate the effects of diminishing returns and ecological damage, around 120 TW, or six times the current consumption rate.
Given diminishing returns as explained in points about limits to growth, that's not likely.
Back in 2006, the IEA stated there's no peak oil because it's simply an "above-ground" problem or political, that by 2015 oil demand would reach 115 Mbd and that oil producers would easily meet it. By 2008, the world economy crashed due to increasing debt, and the IEA began a global survey of world oil production. By 2010, the IEA admitted that peak oil is an "underground" problem, and that world conventional production has been peaking. During the next decade, oil prices would become volatile as more debt was created to mitigate damage caused by increasing debt and used to finance the oil industry, whose debts had by the middle of the decade reached $2.5 trillion. Meanwhile, higher oil prices damaged the world economy, leading to low growth throughout.
In short, it will be very difficult to increase energy production to a scale that would make more people prosperous and thus lead to a peak in population. Given that, what will likely happen is that population will peak due to greater suffering as the effects of diminishing returns coupled with those of ecological damage (including global warming) become more pronounced, not to mention increasing debts and "black swans" like fallout from financial risk-taking, from increased vectors for the spread of disease, from multi-fold increase in world arms production and deployment, etc.
