Karin M. Krchnak, AB, JD
In the several minutes it takes to read this abstract, approximately 1000 people will be added to the planet. With rapid population growth and increased consumption in industrialized countries, one-third to one-half of Earth’s land surface has been transformed, and 50% of the original forest cover has been cleared.2 A sixfold increase in global freshwater consumption occurred between 1900 and 1995 alone, with studies estimating that by 2025, two out of every three of people on Earth will live in water-stressed conditions.5,14
Wildlife is feeling the human footprint on resources as humans have changed hydrologic cycles, contaminated air and water, converted land for agriculture and industry as well as urban sprawl, and altered climate patterns. Population pressures and overuse of resources are pushing diverse and important ecosystems over the brink. A study of 50 countries in Asia and Africa found that the loss of natural habitat was greatest in areas of high population density and least in low-density areas.6 Extinction rates are currently estimated anywhere between 100 to 1,000 times greater than normal.7,12 The loss of top predators (such as Florida panthers and cougars) and keystone species (such as prairie dogs and orangutans) due to human population pressures are causing imbalances in ecosystems that are yet to be fully understood.
While population growth is a driving force behind a number of the world’s environmental problems, water quality and water quantity may be the most critical. Water is the most precious resource; only about 1% of the planet’s water—contained in rivers, lakes, wetlands, and shallow aquifers—is easily accessible for human use.10 Currently, humans use over half of all available freshwater. The use and misuse of water resources are resulting in less free and clean water to support wildlife. If consumption per person remains steady, by 2025, humans could be using 70% of the total because of population growth alone. If per capita consumption reached the level of developed countries, humans could be using 90% of available water each year.8
As humans have diverted, dammed, and altered water systems, the loss of rich freshwater ecosystems and the wildlife that depend on them are increasing. Close to 69% of all freshwater dolphins are threatened with extinction, along with 70% of freshwater otters. In North America, 67% of all mussels, 51% of crayfish, 37% of fish, 40% of amphibians and 75% of all freshwater mollusks are either rare, imperiled or already gone. Of California’s native fish, 63% are extinct, endangered, vulnerable or in decline. In Europe, 42% of all freshwater fish are threatened or going extinct, as are 33% of Australia’s.1,9
In particular, cave or subterranean freshwater species (those known and many yet to be identified) are being affected by human manipulation of the water tables; some of these species may have important ecologic functions that humans may not realize until it is too late.13 Although a captive breeding program in 14 North American facilities may save it from the finality of extinction, the Chinese alligator will probably not survive in the wild beyond another decade.2,11 Countless other species, both in the United States and abroad, may share similar fates.
Unfortunately, global data sets on biodiversity are lacking, and thus the planet may be losing species before they can even be identified. There is also incomplete information on the water needs of ecosystems. However, some have placed the global value of freshwater wetlands, including related riverine and lake systems, at close to $5 trillion per year. This is based on their value as flood regulators, waste treatment plants, and wildlife habitats, as well as for fisheries production and recreation.4
Although the ultimate value of identified and unidentified species may be unknown, there is growing recognition that rapid population growth, increased urbanization, and the consumption of resources combined are putting enormous pressure on the environment. One of the hardest parts in working toward a healthy future for all is making the link between what happens in our own backyards and the events in places very far from our own home. Zoo veterinarians and other zoo professionals are the ideal advocates for slowing population growth and reducing population pressures to help find a balance between people and wildlife. Despite the difficulty in valuing ecosystems, zoo officials appreciate the importance of protecting and maintaining biodiversity, wildlife habitat and the vast array of ecosystems that make up our planet.
Regardless of the rate at which human population grows in the coming decades, some level of population growth will occur. There is strong evidence that assistance for women’s and girls’ health, education, and reproductive services under international family planning programs helps lower fertility rates and slow population growth, thereby improving both human wellbeing and environmental quality. The United States made a commitment at the 1994 International Conference on Population and Development (ICPD) in Cairo to provide funding for development assistance to help make family planning universally available by 2015. The United States has consistently fallen far short of fulfilling its obligations, ranking last among industrialized countries.
Success in ensuring a healthy future requires action at all levels—international, regional, national and local. On the international level, the Rio+10 Conference as well as the Cairo+10 Conference will be held in 2002 and 2004, respectively, offering humans the chance to evaluate trends and conditions and to debate future action agendas. Regionally, countries and organizations are discussing ecosystem management as a strategy for better addressing the needs of resources and wildlife. On a national level, discussions over changes to the Endangered Species Act may have immeasurable impacts on the survival of wildlife. Empowerment of communities on the local level to manage resources, particularly freshwater, is a potentially powerful tool that is not always explored. Zoo professionals can play significant roles on each of these levels by moving from awareness to activism on the issues.
A vital part of the long-term solution is recognition of the links between rapidly growing populations, escalating demand and shrinking supplies. Slowing population growth will mean that ecosystems that sustain life have the chance to adapt and replenish themselves to meet the needs of humans and wildlife for centuries to come. The work of the National Wildlife Federation’s Population & Environment Program to help build the political will and behavioral changes necessary to ensure a sustainable future offers examples of ways in which zoo professionals can help work toward solutions to these complex issues. The Population & Environment Program’s upcoming publications, Population & Endangered Species and Population, Water & Wildlife: Finding the Balance, will provide for debate and dialogue on the interconnectedness of population and environment issues and how each and every person can make a difference in finding a balance between people and nature.
1. Abramovitz, Janet. 1996. Imperiled Waters, Impoverished Future: The Decline of Freshwater Ecosystems. Worldwatch Paper No. 128, March, 1996. Washington D.C.; Worldwatch Institute.
2. Bryant, D., D. Nielsen, and L. Tangley. 1997. The Last Frontier Forests. Washington, D.C.; World Resources Institute.
3. China’s State Environmental Planning Agency. 2000. State of the Environment Report 1999, at www.sepa.gov.cn/soechina99/water/waterdown.htm. (VIN editor: This link was not accessible as of 2-23-21.)
4. Costanza, R., R. E’Arge, R. De Groot, S. Farber, M. Grasso, B. Hannon, K. Limburg, S. Naeem, R. O’Neill and J. Paruelo. 1997. The value of the world’s ecosystem services and natural capital. May 15, 1997. Nature. 387.
5. Gardner-Outlaw, T. and R. Engelman. 1997. Sustaining Water, Easing Scarcity: A Second Update. Washington D.C.; Population Action International.
6. Harrison, P. 1997. Population and Sustainable Development: Five Years after Rio. New York; United Nations Population Fund.
7. Mace, G. 1998. Getting the measure of extinction. People and the Planet. 7(4).
8. Postel, Sandra, G. Daily and P. Ehrlich. February 9, 1996. Human Appropriation of Renewable Freshwater. Science. Vol. 271, No. 5250.
9. Revenga, Carmen, Jake Brunner, Norbert Henninger, Ken Kassem and Richard Payne. 2000. Pilot Analysis of Global Ecosystems—Freshwater Systems. Washington DC; World Resources Institute.
10. Shiklomanov, I. 1993. World freshwater resources. In: Peter H. Gleick, ed. Water in Crisis: A Guide to the World’s Fresh Water Resources.
11. Topping, Audrey R. 1998. Yangtze’s Dolphins Threatened. April 29, 1998. Earth Times.
12. Vines, G. 1999. Mass Extinctions. New Scientist (December 11, 1999; Special Supplement).
13. World Conservation Monitoring Centre-Freshwater, Freshwater Biodiversity: a preliminary global assessment, at www.unep-wcmc.org/resources-and-data/freshwater-biodiversity—a-preliminary-global-assessment.
14. World Meteorological Organization (WMO). 1997. Comprehensive Assessment of the Freshwater Resources of the World. Geneva; WMO.