Environmental Science 15th Edition by Scott Spoolman,Tyler Miller

Exercise 21

HOW LONG CAN THE HUMAN POPULATION KEEP GROWING?
Are there physical limits to human population growth and economic growth on a finite planet? Some say yes. Others say no.
The debate over possible limits to the growth of human populations and economies has been going on for more than 200 years. Meanwhile, natural capital degradation (Figure 6.2) has occurred widely and grown more intense. The earth's life-support system has been resilient enough to withstand such widespread disturbances.
However, at some point, we could reach one or more planetary boundaries or ecological tipping points (see Figure 3.A, p. 58). Exceeding such boundaries could lead to damaging long-term changes and the possibility of a sharp decline in the human population due to increasing death rates.
To some analysts, the key problem is the large and rapidly growing number of people in less-developed countries (see Table 1.1, p. 13). To others, the key factor is overconsumption in affluent, more-developed countries because of their high rates of resource use per person. Thus, they debate over which is more important for shrinking the human ecological footprint: slowing population growth or reducing resource consumption. Some call for doing both.
Another view of population growth is that, so far, technological advances have allowed us to overcome the environmental limits that all populations of other species face and that this has had the effect of increasing the earth's carrying capacity for our species. Proponents of this view point out that average life expectancy in most of the world has been steadily rising, despite warnings that we are seriously degrading our life-support system.
Some of these analysts argue that because of our technological ingenuity, there are few, if any, limits to human population growth and resource use per person. They believe that we can continue ever-increasing economic growth and avoid serious damage to our life-support systems by making technological advances in areas such as food production and medicine, and by finding substitutes for resources that we are depleting. As a result, they see no need to slow population growth or resource consumption.
Proponents of slowing and eventually stopping population growth point out that in addition to degrading our life-support system, we are failing to provide the basic necessities for about 1.4 billion people-one of every five on the planet-who struggle to survive on the equivalent of about $1.25 per day. This raises a serious question: How will we meet the basic needs of the additional 2.6 billion people projected to be added between 2013 and 2050?
No one knows how close we are to environmental limits that some analysts say eventually will reduce the size of the human population primarily by sharply increasing the human death rate. These analysts call for us to confront this vital scientific, political, economic, and ethical issue.
Critical Thinking
Do you think there are environmental limits to human population growth? If so, how close do you think we are to such limits? Very close, moderately close, or far away? Explain.