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HAT Forum - “World Population”

  • The 519, Rm 304 (check lobby screen) 519 Church Street Toronto, ON, M4Y 2C9 Canada (map)

World population - Estimates and Consequences

In 2014, overturning 20 years of consensus of a 9 billion peak, the UN Population Division projected a global population of about 10 ± 1 billion in 2050, with a peak of about 11 ± 1 billion in 2100. These estimates were based on a statistical analysis of population growth trends and identified India and sub- Saharan Africa (especially Nigeria) as areas of problematically high growth. As well, China's birth rate was expected to increase, presumably because of the demise of the one-child policy. /1/

In response,


, another expert group, forecast global populations back into the familiar 9 billion

range over the 2050 to 2100 timeframe. Their updated model included input from 550 population

experts and, significantly, included the effects of education on fertility. IIASA also estimated a 50%

lower growth rate for Nigeria than did the UN and assumed that China's birth rate would not rise. /2/

Both the UN and IIASA agree that food supply will be a problem. A review of food demand estimates

that world crop production will need to double to feed 9 billion in 2050, primarily because of an

expected increase in protein demand in developing countries. The review assumes that meat eating in

developing countries will increase in proportion to increased affluence. /3,4/

Canadian journalist John Ibbitson and political scientist Darrell Bricker have highlighted the IIASA findings in their new book, Empty Planet, where they posit that the world will face the challenge of a decreasing population. They also cite a Deutsche Bank study which estimates a 2050 peak of 9 billion with a fall to 8 billion in 2100. Demographer Paul Morland, commenting on Empty Planet, largely agrees with the population estimates but disagrees with the authors' view that mass migration to westernized countries will be a "declining wave" with minimal political consequences.

In this, and other regards, Africa appears key. IIASA concluded in a recent (Feb. 2019) paper: "Africa’s

future population growth will be relevant for the rest of the world. Whether it will 'only' increase to two

billion as shown by optimistic scenarios that assume successful implementation of the sustainable

development goals , or by more-pessimistic scenarios assuming slow or stalled development and thus

resulting in four to five billion Africans by the end of the century, Africa’s future population growth will

first of all impact on the future of living conditions and quality of life of Africans. But it will also affect

other continents due to out-migration pressure, global environmental impacts, and, of course, the

efforts needed to live up to the promise to eradicate poverty, hunger, and premature death in all

corners of the planet. Continued rapid population growth will make this an up-hill battle. Education is

currently underfunded, particularly in Africa. A new effort for massive investment in education,

particularly of girls, will not only help to slow this growth but will also empower Africans and create the

human capital needed for rapid social and economic development and sustainable increases in human


1 International Institute for Applied Systems Analysis

Regarding the environmental stresses of feeding our current 7.7 billion people, a recent report (Biological Conservation 232 (2019)) notes the criticality of insects to agriculture and claims that current practices may lead to the extinction of 40% of insect species over the next few decades due to habitat loss, pollution, pathogens/introduced species, and climate change. The authors argue that it is necessary that we move to sustainable, ecologically-based practices and that we significantly reduce pesticide use. However, at the current state of the art, such a change would result in a production shortfall of up to 30%.

Proposed strategies to deal with this shortfall and to increase the food supply to feed 9 billion

include: enhancing yields, improving efficiency, shifting diets and reducing waste. The experts seem to

be in agreement that our current agricultural footprint should not be increased, but most are optimistic

that the 2050 needs can be met. (see, e.g.

billion-people-2050-21-charts Dec. 5, 2018)


1. How likely is it that the global population can be kept to 9 billion and what are the consequences of


2. If Africa really is the prime demographic issue, how can the developed world help without fostering


3. Is the developed world willing to make the changes required to feed 9 billion people on the same

agricultural footprint and what are the consequences if we fall short?

4. If we get over the population peak, what is a desirable population level for the world and for Canada?


2. World Population and Global Human Capital in the 21st Century Lutz, Butz and KC, Oxford University Press (2014).

3. "A World With 11 Billion People? New Population Projections Shatter Earlier Estimates", National Geographic, (Sept., 2014).

4. "The New Food Revolution", National Geographic, (May, 2014).

1. "World Population Prospects: 2017 Revision", UN Dept. of Economics and Social Affairs,


5. "Stalls in Africa’s fertility decline partly result from disruptions in female education.", Kebede E, Goujon A, Lutz W (2019) PNAS. doi:10.1073/pnas.1717288116 []

Earlier Event: March 2
HAT Forum - "The Isms"