Since prehistoric times, human population growth has led to the extinction of other species. This trend existed tens of thousands of years ago and continues to date, with an estimated increase of 7% in the number of threatened species by the year 2020. Using insights from paleoanthropology, Professor Jeffrey McKee examined the impact of a population boom on biodiversity conservation.

The human wedge

"Extinction is normal", said McKee, pointing out that 99.9% of all species that ever lived were extinct and that the earth replenishes its biodiversity every 1-10 million years. However, he claimed that current high levels of population growth were creating greater threats to other species than ever before.

McKee noted "Growth of population is having profound effects on biodiversity worldwide". He referred to this as the human wedge. According to McKee, while prehistoric humans had some impact, the human population today has a much larger wedge, resulting in increasing threats to other species.

Early Homo and extinction

McKee discussed the period of Early Homo's existence, when a number of extinctions had occurred. He theorized that climate change was largely responsible for these occurrences. Early Homo and another hominid- Australopithecus were not large wedges. In comparison, Homo erectus had a larger brain and body and consumed more. Fossil evidence shows that other large mammal species competing with Homo erectus went extinct. Research points to a rise in the number of extinctions in South Africa, the near East, Western Europe and North America coinciding with the entry of Homo erectus in these areas.

The next big event in human and ecological history, McKee argued was the beginning of agriculture 10,000 years ago. McKee refuted some scientists' claims that the advent of agriculture led to a human population explosion. Rather, he argued based on his own calculations, that the population boom was due purely to exponential growth. He did agree that agriculture led to sustained human population growth that in its absence would have leveled off much sooner. In ecological terms, according to McKee, agriculture led to an increase in extinctions as humans focused natural resources on producing food for people, rather than fostering biodiversity.

McKee highlighted the extent of current extinction rates, by estimating that at a minimum, there is one extinction per hour, at a maximum 43 per hour. Previous patterns in Africa suggest that every 100,000 years 4 large mammal species arose and 4 large went extinct. This pattern has now changed in size as well as scope. Human activity is affecting all species through changing their habitats.

McKee viewed population density as a highly significant variable in the estimation of the number of threatened species in a region. He emphasized the importance of reducing current population growth levels, to reduce the total human population and lessen impact on biodiversity.

Counting heads and feet

McKee argued conservation programs have proven difficult and ineffective in protecting all but small areas of the globe. Calling for an alternative, he recommended addressing human population growth rates to reduce species extinction-- suggesting that it would be easier to reduce human population growth through increased access to voluntary family planning and girls' education rather than conservation programs alone.

McKee acknowledged that his views faced opposition from ecologists, who regard consumption, or the ecological footprint of individuals, as more important than raw population figures. He countered these arguments by pointing out that there was no relationship between a country's Gross National Product, a measure of its consumption, and threatened species per area. He suggested that poor countries had a large direct impact on species extinction, whereas developed countries' consumption patterns made their impact more indirect. McKee summarized his position on the effect of population growth and consumption patterns on species extinction by saying "Count heads, mind your feet."

Equity and international differences

The lively discussion that followed McKee's talk raised important considerations related to equity. A participant raised the issue that developed nations and industrialized economies were being shielded from responsibility by using simple correlations that held the Global South to blame. McKee responded, "Charity should begin at home", and acknowledged that in addition to reducing population growth rates in developing countries, developed countries need to address consumption and their own use of natural resources.

Another questioner noted that extinction was a global crisis, whereas population policies and politics tended to be local. McKee's solution to the problem included policies that focused on education, community decision-making, greater empowerment of women and promoting their direct access to contraceptives and family planning materials. He also advocated an end to the global gag rule.

Participants pointed out that the number of threatened species might not be a politically popular measure of conservation, particularly in developing countries. In response, McKee reiterated that without population being addressed, all the conservation efforts in the world would not make any difference.

Discussion also centered on the fact that resource rich countries had a large number of the world's poor. Poor governance was cited as the major reason, with a participant suggesting that improving governance was as vital as family planning.

Another discussant recommended a multi-sectoral approach amongst environmental and population organizations and their funding agencies. He acknowledged that there were currently tremendous organizational challenges in coordinating their activities. He recommended that conservationists carry out a gap analysis to indicate the ideal allocation of spending on family planning to population organizations.

Click here for the entire Spring 2004 issue of PECS.

Glossary of terms used:

4.4 millions years ago the first hominids appeared, predating the first Homo species. They had not yet developed the large brain, teeth structure, and skeletal features of humans and are known as Australopithecus.
Source: Introduction to the Australopithecine species
Angela Bonet-Garcia, Tracey Cameron, Kathy DeCocq, Adam Drake, and
Amber Greer, DeKalb College, Georgia June 1997.

Early homo
Early Homo's brain was usually between 650 and 775 cc, which gave it greater capacity than that of the Australopithecines but less than that of Homo erectus.
Source: Anthropology course guides
Richard Effland, Mesa Community College, Mesa Arizona

Drafted by Ira Athale and Jennifer Kaczor.