coauthors of Nature's Place: Human Population and the Future of Biological Diversity, advance the belief that human population growth is among the primary causes for mass extinctions that have recently been sapping the biodiversity of the planet. While a reduction in human population growth rates "will not end human-caused extinctions," they note, Cincotta and Engelman express hope that it will help ecosystem conservation. "Conservationists will continue to contend with our species' unprecedented densities, its geographic range and mobility, its need for natural resources and ways to dispose of wastes, and its use of technologies," they observe. "The possibility of world population stabilization, in combination with modest decline in some regions, nonetheless offers among the greatest hopes for the future of species and ecosystem conservation on a human-dominated planet."

Meanwhile, trends indicating steadily aging communities in many first world countries worry social scientists, who warn of potential economic disasters. As less adults of child-bearing age reproduce in some nations, the rate of population replacement has sunk to all-time lows. Combined with life-extending medical care and other means for expanding lifespans, the average age in those countries has climbed to historic highs. While extended lifespans and lower populations may initially seem positive, many argue that they carry with them potential economic hardship. They note, for example, that as the population ages, the elderly accumulate a significant financial cost from increased medical expenses and lower economic productivity. As a result, warns Peter G. Peterson, former chairman of the Federal Reserve Bank of New York, "If we don't prepare for this challenge, much of what is good about an aging society could turn sour. After all, how will young and old live happily together if they see themselves as competitors for scarce resources?" Peterson asks, "[Will] the aged be praised for increasing the quality of life if they are deemed responsible for bankrupting the global economy?"

Solutions to potential population crises generally do not come easy. The most common approach to the population boom, as paraphrased by Carol A. Kates, a professor of philosophy at Ithaca College, is the need to "limit reproduction and, by extension, the unsustainable use of environmental resources in production and consumption." This approach, she points out, is often anathema to religious conservatives. Finding fixes to these complicated moral and social issues remain clouded and as yet undetermined.

Resources
Cincotta, Richard, and Robert Engelman. "Stabilizing Human Population Growth Would Help Preserve Biodiversity." Biodiversity. Ed. William Dudley. San Diego: Greenhaven Press, 2002.
Kates, Carol A. "Aggressive Population Control Policies Should Be Supported." Population.. Ed. Karen F. Balkin. Opposing Viewpoints. San Diego: Greenhaven Press, 2006.
Peterson, Peter G. "The Growing Elderly Population Is a Serious Problem." Current Controversies: The Elderly. At Issue Series. Ed. Tamara Thompson. Detroit: Greenhaven Press, 2006.

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