The world’s population has reached the symbolic milestone of adding another billion to this planet. While 7 billion is a static number, the expansion and distribution of the world’s population is a very dynamic issue that a single map of where these 7 billion are living (as shown on this website back in July) does not do full justice of what is happening on the planet of people. A lot has changed from the 2.5 billion people that lived on the planet in the middle of the last century to today’s 7 billion, moving the gravitational centre of people considerably towards Asia. This has now started turning towards the African continent, which has not only been a considerable part of the global population growth over the last quarter of the century (and is therefore home to a large share of the world’s children), but is expected outnumber Asian population growth considerably in the decades to come.
The following cartogram-map animation shows these changing trends between 1950 and 2100. It is based on United Nations probabilistic population projections of total fertility from the 2010 Revision of the World Population Prospects. From the year 2010, the data is based on a future projection of expected population changed. “To project the population until 2100, the United Nations Population Division uses assumptions regarding future trends in fertility, mortality and international migration. Because future trends cannot be known with certainty, a number of projection variants are produced” (quoted from the WPP documentation). I used the data from the probabilistic median variant, in which the population is expected to grow to approximately 10 billion by the year 2100 (see below for a graph of the different scenarios produced by the UN). The animation therefore shows the changing distributions of population between the different countries (note that South Sudan is not included in the estimates; Sudan is therefore treated as one country in this map), with Europe losing large shares of population in total as well as in relation to the rest of the world, while the dominance of Asia slowly starts to be relativised by the increasing population shares on the African continent, making the changes in the Americas almost insignificant from a global perspective:
Apparently, this animation outlines one possible scenario how the global population shifts may develop over the next 90 years. It may all come very different, and depending on what assumptions one makes about our behavior of how we reproduce ourselves, we could as well start becoming less people much earlier – or continue to grow exponentially. The UN Population Prospects takes different scenarios into account, of which the above animation shows the median prospects. The other variations of how the world’s population may develop can also be assessed in further detail as shown above. The following graph gives an overview of the different projections, and the detailed data can be obtained from the UN WPP website (see http://esa.un.org/wpp/unpp/panel_population.htm).
With 7 billion marking another milestone in our presence on the planet, old debates about the maximum sustainable human population will come up once again, often diffusely mixed with discussion about migration and overpopulation on a national level (yet they have often been proven wrong before).
Maybe there will be 10 billion of our species around in 2100. Maye much fewer, or even more. Perhaps we should be less obsessed by counting and predicting our growth (and decline), but about the things that really matter. Whether we are too many or even too few depends a lot on how we live our lives on this planet. There could be enough space, and enough resources for all of us, we just have to live slightly less stupid in some parts of the world to make us all a bit more happy.