In an July 17 Denver Post article "Milestone portends millstone: World's 6 billionth
inhabitant due" [also printed in the Los Angeles Times], Zero Population Growth national spokesman Peter Kostmayer claims that "population
growth momentum" (the tendency of population to increase for 70 years after
reaching replacement level fertility) is the main reason U.S. population is
projected to exceed one-half billion by 2060.
While Mr. Kostmayer's explanation is politically correct, it is wrong. U.S.
fertility has been at or below replacement level for nearly 30 years. If
"momentum" were the primary factor, U.S. population would stabilize in the next
few decades. But U.S. Census projections indicate continued growth through
2050, with a greater increase in 2050 than in 1999.
If mass immigration would have been reduced to traditional levels in 1970, U.S.
population would stabilize at about 230 million in 2050 -- 40 million below our
current population. Thus the primary reason U.S. population is projected to
double by 2060 is mass immigration. In spite of these facts, ZPG (now Population Connection) claims that
"immigration is only a small part of U.S. population growth."
-- Kim Berry
Robin Wright says in her July 17, 1998 article
(see http://www.latimes.com/, search for "Y6B"):
"The U.S. fertility rate, or average number of births per woman, has dropped to
"Yet the United States has the highest fertility rate among wealthy
industrialized countries. And because of the "momentum" of population
growth--it takes about 70 years for the population to stabilize after a nation
reaches a replacement-level fertility rate of 2.1 births per woman--the United
States is expected to double its population of 270 million in 60 years if the
current growth rate continues, according to Peter Kostmayer, national spokesman
for Zero Population Growth."
U.S. Census Bureau projection of annual U.S. population, 1996 through 2050. The "high series" is referenced in the above response, since that is apparently the table Kostmayer is using to project 540 million by 2060. The Census Bureau has not made any projection beyond 2050, however.
NPG paper: The Impact of Immigration on United States' Population Size: 1950 to 2050 by Dr. Leon F. Bouvier.
Response by Ed Lytwak of Negative Population Growth to Peter Kostmayer's
misleading claim that "births due to unplanned pregnancies will contribute far
more this year to U.S. population growth than immigration."
ZPG statement: "We think that immigration is only a small part of population growth."
"Numbers USA" has an outstanding population graph showing the impact of
immigration on our future.
Additional sources of data: EcoFuture Population Data
Population Reference Bureau.
Rule of 70 and calculating doubling times.