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Human population reduction is not a quick fix for environmental problems

Citation

Bradshaw, CJA and Brook, BW, Human population reduction is not a quick fix for environmental problems, National Academy of Sciences of The United States of America. Proceedings, 111, (46) pp. 16610-16615. ISSN 0027-8424 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 The Authors

DOI: doi:10.1073/pnas.1410465111

Abstract

The inexorable demographic momentum of the global human population is rapidly eroding Earth’s life-support system. There are consequently more frequent calls to address environmental problems by advocating further reductions in human fertility. To examine how quickly this could lead to a smaller human population, we used scenario-based matrix modeling to project the global population to the year 2100. Assuming a continuation of current trends in mortality reduction, even a rapid transition to a worldwide one child policy leads to a population similar to today’s by 2100. Even a catastrophic mass mortality event of 2 billion deaths over a hypothetical 5-y window in the mid-21st century would still yield around 8.5 billion people by 2100. In the absence of catastrophe or large fertility reductions (to fewer than two children per female worldwide), the greatest threats to ecosystems—as measured by regional projections within the 35 global Biodiversity Hotspots—indicate that Africa and South Asia will experience the greatest human pressures on future ecosystems. Humanity’s large demographic momentum means that there are no easy policy levers to change the size of the human population substantially over coming decades, short of extreme and rapid reductions in female fertility; it will take centuries, and the long-term target remains unclear. However, some reduction could be achieved by midcentury and lead to hundreds of millions fewer people to feed. More immediate results for sustainability would emerge from policies and technologies that reverse rising consumption of natural resources.

Item Details

Item Type:Refereed Article
Keywords:demography, fertility, catastrophe, war, mortality
Research Division:Studies in Human Society
Research Group:Demography
Research Field:Population Trends and Policies
Objective Division:Economic Framework
Objective Group:Macroeconomics
Objective Field:Demography
Author:Brook, BW (Professor Barry Brook)
ID Code:97896
Year Published:2014
Web of Science® Times Cited:19
Deposited By:Biological Sciences
Deposited On:2015-01-21
Last Modified:2015-04-20
Downloads:0

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