A while back, I wondered in which year the World population would be twice what it was when I was born, but couldn’t find a simple table on the web to answer this (I still can’t, so I’m sharing the following table in this blog). It’s a simple matter to look up the answer if we have both historical census figures (estimates of course) and future world population projections. The US Census Bureau provides a nice table with both, here. Their figures are for mid-year population, and the following data were copied on 2013-09-03.

So, for anyone born between 1950 and 1983, we can find the estimated ‘Birth World Population Doubling Year’ (BWPDY below). Mine just happens to be this year! We can make the time estimate a bit finer than just the year: I was born in January 1968, with an interpolated population of ca. 3,530,000,000. Interpolating again, twice that (7,060,000,000) was hit probably in January 2013, i.e., close to my own 45th Birthday!

Of course, these figures are all estimates, but the process of calculating this ‘Doubling Year,’ and even celebrating it (or mourning it) on a chosen ‘Doubling Day’ (one’s birthday in the Doubling Year?) is an informative and powerful reminder of the reality of exponential growth. Of course, as population growth slows, we have to wait longer and longer for a Doubling Year; for example, someone born four years after me must wait eight more years for their Doubling Year. And people born after 1982 are (currently) unlikely to see the World’s Population double.

Now... just try to imagine what it means for there to be twice as many humans on our planet than when we ourselves arrived!

``````  Year  Population     Population x 2  BWPDY
====  =============  ==============  ====
1950  2,557,628,654   5,115,257,308  1988
1951  2,594,919,657   5,189,839,314  1988
1952  2,636,732,631   5,273,465,262  1989
1953  2,681,994,386   5,363,988,772  1990
1954  2,730,149,884   5,460,299,768  1992
1955  2,782,001,154   5,564,002,308  1993
1956  2,835,182,293   5,670,364,586  1994
1957  2,891,211,793   5,782,423,586  1996
1958  2,947,979,287   5,895,958,574  1997
1959  3,000,544,325   6,001,088,650  1998
1960  3,042,828,380   6,085,656,760  1999
1961  3,083,799,968   6,167,599,936  2001
1962  3,139,919,051   6,279,838,102  2002
1963  3,209,631,895   6,419,263,790  2004
1964  3,280,981,862   6,561,963,724  2006
1965  3,350,186,115   6,700,372,230  2007
1966  3,420,416,498   6,840,832,996  2009
1967  3,490,051,163   6,980,102,326  2011
1968  3,562,007,503   7,124,015,006  2013
1969  3,636,825,800   7,273,651,600  2015
1970  3,712,338,708   7,424,677,416  2017
1971  3,789,941,225   7,579,882,450  2019
1972  3,866,158,404   7,732,316,808  2021
1973  3,941,664,971   7,883,329,942  2023
1974  4,016,159,586   8,032,319,172  2025
1975  4,088,619,689   8,177,239,378  2027
1976  4,159,715,844   8,319,431,688  2030
1977  4,231,636,519   8,463,273,038  2032
1978  4,303,675,842   8,607,351,684  2034
1979  4,378,583,227   8,757,166,454  2037
1980  4,450,924,299   8,901,848,598  2040
1981  4,533,807,914   9,067,615,828  2043
1982  4,613,830,568   9,227,661,136  2046
1983  4,694,935,057   9,389,870,114  (may never double)
1984  4,773,643,742   9,547,287,484    "
1985  4,855,387,634   9,710,775,268    "
1986  4,939,332,441   9,878,664,882    "
1987  5,025,796,394  10,051,592,788    "
1988  5,113,007,284  10,226,014,568    "
1989  5,199,760,484  10,399,520,968    "
1990  5,287,166,778  10,574,333,556    "
1991  5,370,142,696  10,740,285,392    "
1992  5,455,057,523  10,910,115,046    "
1993  5,537,583,721  11,075,167,442    "
1994  5,618,516,091  11,237,032,182    "
1995  5,699,516,291  11,399,032,582    "
1996  5,779,912,412  11,559,824,824    "
1997  5,858,582,659  11,717,165,318    "
1998  5,936,039,484  11,872,078,968    "
1999  6,013,121,531  12,026,243,062    "
2000  6,089,810,661  12,179,621,322    "
2001  6,166,582,980  12,333,165,960    "
2002  6,243,351,444  12,486,702,888    "
2003  6,319,822,330  12,639,644,660    "
2004  6,396,726,866  12,793,453,732    "
2005  6,473,525,274  12,947,050,548    "
2006  6,551,256,997  13,102,513,994    "
2007  6,629,668,134  13,259,336,268    "
2008  6,708,196,774  13,416,393,548    "
2009  6,786,381,274  13,572,762,548    "
2010  6,863,770,931  13,727,541,862    "
2011  6,940,712,355  13,881,424,710    "
2012  7,017,543,964  14,035,087,928    "
2013  7,095,217,980  14,190,435,960    "
2014  7,172,800,105  14,345,600,210    "
2015  7,250,104,524  14,500,209,048    "
2016  7,327,047,197  14,654,094,394    "
2017  7,403,533,981  14,807,067,962    "
2018  7,479,340,547  14,958,681,094    "
2019  7,554,324,522  15,108,649,044    "
2020  7,628,361,509  15,256,723,018    "
2021  7,701,503,831  15,403,007,662    "
2022  7,773,787,217  15,547,574,434    "
2023  7,845,094,405  15,690,188,810    "
2024  7,915,343,988  15,830,687,976    "
2025  7,984,471,678  15,968,943,356    "
2026  8,052,555,718  16,105,111,436    "
2027  8,119,653,594  16,239,307,188    "
2028  8,185,704,067  16,371,408,134    "
2029  8,250,680,127  16,501,360,254    "
2030  8,314,556,118  16,629,112,236    "
2031  8,377,397,726  16,754,795,452    "
2032  8,439,275,616  16,878,551,232    "
2033  8,500,179,665  17,000,359,330    "
2034  8,560,091,213  17,120,182,426    "
2035  8,618,975,745  17,237,951,490    "
2036  8,676,879,132  17,353,758,264    "
2037  8,733,854,464  17,467,708,928    "
2038  8,789,875,606  17,579,751,212    "
2039  8,844,910,290  17,689,820,580    "
2040  8,898,921,851  17,797,843,702    "
2041  8,951,939,549  17,903,879,098    "
2042  9,003,999,017  18,007,998,034    "
2043  9,055,061,670  18,110,123,340    "
2044  9,105,083,460  18,210,166,920    "
2045  9,154,029,673  18,308,059,346    "
2046  9,201,933,427  18,403,866,854    "
2047  9,248,825,693  18,497,651,386    "
2048  9,294,674,737  18,589,349,474    "
2049  9,339,454,816  18,678,909,632    "
2050  9,383,147,855  18,766,295,710    "
``````