Well, easy to calculate, there wouldn't be many effects. But at least, on which axis would the earth imperceptibly move?
Here's a quick script to compute it, under the following main (ultra-)simplifications:
- Everybody weighs the same and we all jump at the same height and in the same way
- The population of each country is equally distributed within it (which is extremely inaccurate but I don't care)
Yes, it's equivalent to computing the center of mass of the world population, but in this way it sounds more cool.
The data was retrieved from the following:
- popolazione.csv - World Bank
- coordinate.csv - metal3d on Github