I gave a talk this summer at the annual meeting of the American Scientific Affiliation (ASA) on world energy needs in the year 2100 (audio | slides). One of my assumptions is that by 2100 all countries of the world will have the per capita energy use of a developed western European country (about 130 GJ per person). On a Human Development Index (HDI) vs. Per Capita Energy Use plot, 130 GJ corresponds to an HDI of over 0.9–in the highly developed category.
I was able to give a longer version of that talk at the Southern California section of the ASA that met at Cal Baptist University in January. In the longer version I took a minute to try to convince the audience that the world was indeed on a path of improvement. When I was an undergrad at Purdue and learning about the state of world in the late 70s, population was out of control, poverty was rampant, infant mortality was high, etc. Paul Ehrlich’s The Population Bomb and the Club of Rome’s Limits to Growth sent a very dire message about the future. While there are still many pessimistic messengers, it seems from more recent students of the state of world such as Hans Rosling of Gapminder.org that much progress has been made. See, for example, this video on population growth. Here’s the slide that contrasts Ehrlich and the 70s with Rosling and 2018.
The point of the paper is that world energy demands will be chiefly the result of global population growth (10 billion by 2050 and holding steady) and the development of the currently under-developed countries. This will produce a three-fold increase in global energy demand, from 550 EJ today to around 1600 EJ in 2010.