poly: World Economic History

I got hold of a data series estimating total World Product (WP)
from 1 million B.C. to present. I tried to model it as a
sum of exponentials, and I get a close fit with these 5 terms:

Doubling Time Dominant Period DT factor WP factor
------------- ------------------------- --------- ---------
500,000 yrs 1M B.C. to ~300K B.C. NA 9
140,000 yrs. ~300K B.C. to 5000 B.C. 4 6
    860 yrs. 5000 B.C. to 1700 155 196
     58 yrs. 1700 to 1900 15 11
     15 yrs. 1900 to 2000 4 37

I've listed the doubling time and dominant period of each term.
I also list the factor by which the growth rate increased from
the previous period, and the total WP growth factor for each period.

The big questions to ask are: how soon might the world economy jump
again to a faster growth mode, and how much faster might that be?

If this mode lasts through as large as WP factor as the middle
mode did, we could have another 400 years to go. Or we could be
overdue. The new doubling time might be as slow as four years or
as fast as one month.

It's not clear the first two periods are really different
(the data is bad then). If you merge them you get a doubling
time there of ~190K years, with the rest of the model unchanged.

Compare the model and data in this graph:
http://hanson.berkeley.edu/growth.gif
See the whole analysis in this spreadsheet:
http://hanson.berkeley.edu/growth.xls

Robin Hanson
hanson@econ.berkeley.edu http://hanson.berkeley.edu/
RWJF Health Policy Scholar, Sch. of Public Health 510-643-1884
140 Warren Hall, UC Berkeley, CA 94720-7360 FAX: 510-643-2627
Received on Thu Jun 4 20:31:35 1998