23 September 2014
Demographers from the United Nations Population Division and several universities published a paper in Science last week arguing that there is an 80% probability that world population, now 7.2 billion, will increase to between 9.6 and 12.3 billion in 2100.
On 23 October 2014, IIASA's demographers will announce the results of their newest assessment at the launch of a new book entitled: “World Population and Global Human Capital in the 21st Century” (Lutz, Butz and KC, Oxford University Press 2014). Contrary to the UN projections, the IIASA medium (most likely) scenario indicates that world population will increase to 9.2 billion by 2050, peak at 9.4 billion around 2070 and start a slow decline to 9.0 billion by the end of the century.
Why do these projections differ? Read the reasoning behind the projections in an IASA blog post by Wolfgang Lutz, World Population Program Director and colleagues in IIASA's World Population Program: 9 billion or 11 billion? The research behind new population projections
National Geographic: A World With 11 Billion People? New Population Projections Shatter Earlier Estimates
Dueling projections of population growth present different visions of the world's future.
Nature: World population unlikely to stop growing this century
Baby boom in Africa set to push global population as high as 12 billion by the year 2100, study finds.
The Guardian: World population to hit 11bn in 2100 – with 70% chance of continuous rise
New study overturns 20 years of consensus on peak projection of 9bn and gradual decline
Last edited: 27 February 2015
Interim Deputy Director General for Science Directorate - DDG for Science Department
Principal Research Scholar and Senior Program Advisor Population and Just Societies Program
Principal Research Scholar and Senior Program Advisor Social Cohesion, Health, and Wellbeing Research Group - Population and Just Societies Program
International Institute for Applied Systems Analysis (IIASA)
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