Conferences - Seminars
EESS Special event - talk on "An earth-scientist’s view of human population dynamics"
By Dr Stephen Warren, Professor, Department of Atmospheric Sciences, and Department of Earth & Space Sciences, University of Washington, Seattle, USA
Dr Stephen Warren has been a professor at the University of Washington since 1982. His research interest is the interaction of solar radiation with snow, clouds, and sea ice, and their role in climate. He is a Fellow of AMS, AAAS, and AGU. He has 135 publications, which have been cited about 11,000 times. He has won two awards for excellence in teaching. His interest in population developed from teaching a course on climate change.
Historical examples of demographic change, in China, Italy, Nigeria, Utah, the Philippines, and elsewhere, together with simple mathematics and biological principles, show that stabilizing world population before it is limited by food supply will be more difficult than is generally appreciated. United Nations population projections are based on a logical fallacy in that they assume, in spite of the absence of necessary negative feedbacks, that all nations will converge rapidly to replacement-level fertility and thereafter remain at that level. The benign projections that have resulted from this assumption may have hindered efforts to make availability of birth-control a priority in development-aid.
Education of women and provision of contraceptives have caused dramatic reductions in fertility, but many groups, including some that are well-educated, maintain high fertility. Small groups with persistent high fertility can grow to supplant low-fertility groups, resulting in continued growth of the total population. The global average fertility rate could rise even if each country's fertility rate is falling. In some low-fertility European countries where deaths exceed births, the population continues to grow because of immigration.
Producing more than two offspring is normal for all animal species with stable populations, because their populations are limited by resources or predation rather than birth control. It may therefore be appropriate to view the growth of human population as the result not of excess fertility but rather of excess food. Even if the fertility rate is maintained far in excess of 2, the population cannot grow if food is limiting; instead the additional babies will starve. Without the agricultural advances of the 20th century, world population could not have grown as it did from 1.7 billion in 1900 to 6 billion in 2000.
The food supply may be enhanced in the future by genetic engineering and other innovations, but it may be limited by water shortage, climate change, pollution, and energy shortage. The efficiency of agriculture may be diminished by breakdown of social infrastructure.
Organization EESS - IIE
Accessibility General public
This event is internal