According to the United Nations, the world population surpassed the eight billion mark on November 15, 2022, and reached 8.045 billion on July 1 of this year. But these figures vary significantly from US Census Bureau estimates which placed the global population at just 7.979 billion at the beginning of July.
Population and especially population growth estimates are an important basis for policy. The UN projects that the population will continue to grow into the 2080s when it will reach 10.4 billion. Reacting to these figures, Liu Zhenmin, UN Under‐Secretary‐General for Economic and Social Affairs observed: “Rapid population growth makes eradicating poverty, combatting hunger and malnutrition, and increasing the coverage of health and education systems more difficult.”
Writing in The Guardian, the newspaper’s former environment editor John Vidal concluded “The hard fact is that in an age of climate breakdown, human numbers matter. And the ecological impact of another 2–3 billion humans will be immense.” He went on to note that the Intergovernmental Panel on Climate Change had identified global population growth as one of the two biggest drivers of growing CO2 emissions, the other being increasing GDP per capita.
Concerns about climate change, hunger, and inadequate service provision may be mitigated if the world’s population is growing more slowly and is on course to stagnate earlier than the UN expects.
A country‐by‐country comparison of the UN and US Census figures reveals some large discrepancies in both directions. The accompanying table shows all cases in which the respective estimates differed for a given country by five million people or more.
The UN’s estimate for China is especially doubtful. China’s official population estimate was 1,412 million at the end of 2022 reflecting an 850,000 person drop from the previous year. And the decline is likely to have accelerated in 2023 with demographers forecasting a lower number of births than in 2022 and perhaps a million excess deaths from COVID-19 following the termination of pandemic restrictions.
Chinese authorities have not been forthcoming about COVID deaths adding to suspicions that they are overstating the nation’s population. One independent expert, Yi Fuxian of the University of Wisconsin‐Madison estimates China’s population at no more than 1.28 billion which is at least 130 million below the official figure. Fuxian offers evidence that the Chinese authorities have been systemically overstating births for decades.
He also casts doubt on the UN’s estimate of India’s population. That nation’s last Census, in 2011, found 1.211 people, or about five million less than the UN data show for that year. If fertility has plummeted more than the UN expected the gap between more recent estimates and reality will likely be magnified. We will only know for sure when India conducts its next Census in 2024.
While US Census estimates appear to be better than UN estimates for China and India, both are flawed in the case of the third most populous country, the United States. Both sources place US population at slightly under 340 million as of July 1, 2023 (for the US Census, I’m referring to its International Database data file; a lower number is shown on the Census Bureau’s World Population Clock web page).
However, the US Census Bureau’s July 1, 2022 domestic population estimate was 333 million, reflecting a 1.2 million increase over the prior year and a 1.9 million increase over the 2020 decennial Census. Even with the bounce‐back in population growth post‐pandemic, it is hard to imagine US population totaling more than 335 million as of July 1, 2023, suggesting a five‐million‐person overestimate in both global datasets.
So, there is good reason to believe that the global population did not exceed 8 billion last year and may still be below that milestone in late July 2023. Given the lower 2023 level and apparently slower growth in recent years, the UN’s projection of a 10.4 billion peak in 2086 should also be called into question.
Other researchers have more modest growth expectations. The Institute for Health Metrics and Evaluation projects a peak population of 9.7 billion in 2064, while Earth4All expects a peak of less than 9 billion around 2050 with an even lower maximum if development in poorer nations accelerates.
Whether we should welcome slower population growth is open to debate. While the mainstream view focuses on the threats of overpopulation, Cato’s Marian Tupy welcomes new people as a source of innovation. As Tupy wrote when the world population purportedly hit the 8 billion mark last November: “Every new human being comes to the world not only with an empty stomach, but also a pair of hands, and, more importantly, a brain capable of intelligent thought and new knowledge creation.”
But regardless of whether one welcomes or fears population growth, the policy debate is impoverished by stale and inaccurate data. We often hear that we’re entitled to our own opinions, but not our own facts (a quote often attributed to the late Senator Daniel Patrick Moynihan but which appears to have earlier origins). Yet in this case, the very foundational question of how many people now reside on earth, there is no reliable source of ground truth.