My mathematical model of population and consumption now has an economic component that projects Gross World Product (GWP), global wealth, and wealth distribution backward and forward in time. The latter was aided by the lucky release of a new report on global wealth.
As people pursue happiness as defined in the model, they must seek and manipulate sets of conditions (what I call "environments") that maximize it. Economies are cultural tools for enabling this, so it's not surprising that they can be described in the same terms. One such term dominates this new view of economics: "happy environment."
People who have total life satisfaction occupy environments that are matched to all of their needs and wants. Such matches are uncommon, just like finding the perfect house. But if we could disassemble, move, and assemble all the environments we collectively have access to ("inhabited environments") to make environments that match as many people's wants and needs as possible, each of those environments would be a happy environment.
Our world economy doesn't explicitly traffic in happy environments (to my knowledge, this is a concept that I just invented), but it appears to do the equivalent. From what I can tell, it defines one set of happy environments for actual, physical conditions. It defines another set for all the ways those environments can be manipulated. Then it defines a third set for all the ways the environments and manipulations can be manipulated as abstract entities that embody their value. Mathematically, economic activity (such as that measured by GWP) is proportional to the square of the number of happy environments; and wealth is proportional to the cube of the number of happy environments.
One of the most controversial issues facing people today is the tremendous inequality in the distribution of wealth. If it was distributed purely on the basis of happy environments, this wouldn't be nearly as much of an issue as it is (though it certainly isn't issue for the few people who benefit from it). However, as I discovered while trying to find out how the model could reproduce the actual distribution, our economy apparently uses both happy environments and consumption to determine who has how much wealth, dominated by the latter. Our exhaustion of sources of new environments (and associated resources) has an already focusing effect on wealth distribution, which I plan to elaborate upon later, but this dependency on consumption makes it extreme.
Projections of our economic future follow the same trajectories as happiness and population, which are the factors that define the number of happy environments. Thus, we are probably at the peak of everything, and can expect it all to drop to zero by early in the next century (at the latest). I'm continuing to explore the alternative "best" case, which unrealistically relies on finding and using millions of Earth-equivalent biospheres over the next 800 or so years, which is what it would take to follow our preferred trajectory. If the model's assumptions are accurate that far into the future, then we will once again be at a peak, but it will be an ultimate one.