October 27, 2025. NPR ran a segment on how Populations are Shrinking and Altering the Global Economy. It is somewhat surprising that Population Decline has not been bigger news. It has been going on in many countries and for the entire World System (graphic above with 98% bootstrap prediction intervals).
The United Nations has essentially been making Population projects (graphic above) similar to my WL20 Model at the start of this post.
The basic theoretical model underlying the possible impact of Population Decline is the Kaya Identity (above) used by the IPCC to help understand Global Temperature Change. The Kaya Identity is true by definition (see the Boiler Plate) so any decrease in Population will not only decrease economic growth (Q) but also decrease CO2 emissions and moderate Global Temperature (T).
My models are also predicting that growth in the World System will peak before 2100 (here) as will Global Temperature (here). The reasons are that there are powerful negative feedback loops from environmental and market controllers that eventually limit growth of the World System.
Exercises
You can experiment yourself with one of my World System models here. The models are written in the R programming language and can be run on line. Suggestions in the code, to include bootstrap confidence intervals for choosing reasonable counterfactuals, can be found in the code. The model is stable and cyclical.
Another one of my World Systems models is unstable and produces exponential growth forever (here). When it is stabilized (instructions in the code) the World System reaches a steady state after 2100.
The future could be any one of these models or something else entirely (see the Boiler Plate for IPCC Emission Scenarios). You have to ask yourself which one of the models (if any) seem reasonable.
No comments:
Post a Comment