Page 227 - Environment: The Science Behind the Stories

Average per U.S. resident:
Ecological footprint • $47,310 annual income
2
Projected ecological footprint • 30,300 m of land
• 17.3 metric tons of CO 2
Biocapacity
emitted per year
2.5 Business as usual
Number of planet Earths 1.5 Overshoot sustainability Ecological
2.0
Path to
reserve
1.0
Ecological
0.5

0 debt
1960 1980 2000 2020 2040 2060 2080 2100
Figure 8.22 In the semi-arid sahel region of Africa, popu- Year
lation may be increasing beyond the land’s ability to handle Figure 8.23 The global ecological footprint of the human
it. Here, drought and dependence on grazing agriculture have led population is estimated to be 50% greater than what Earth (a) A family living in the United States
to environmental degradation.
can bear. If population and consumption continue to rise (orange
dashed line), we will increase our ecological deficit, or degree of Average per resident of India:
overshoot, until systems give out and populations crash. If, instead, • $3400 annual income
2
of this chapter has dealt with numbers of people rather than we pursue a path to sustainability (red dashed line), we can eventu- • 2600 m of land
with the amount of resources each member of the population ally repay our ecological debt and sustain our civilization. Adapted • 1.6 metric tons of CO 2
consumes or the amount of waste each member produces. The from WWF International. 2010. Living planet report 2010. Published by WWF- emitted per year
environmental impact of human activities, however, depends World Wide Fund for Nature. © 2010 WWF (panda.org), Zoological Society of
not only on the number of people involved but also on the London, and Global Footprint Network.
way those people live. Recall the A (for affluence) in the IPAT
equation. Affluence and consumption are spread unevenly
across the world, and wealthy societies generally consume leaves only 14% of global resources—energy, food, water, and
resources from regions far beyond their own. other essentials—for the remaining four-fifths of the world’s
We have explored the concept of the ecological footprint, people to share. It is therefore imperative that we continue
the cumulative amount of Earth’s surface area required to pro- and accelerate efforts to promote renewable energy (Chapter
vide the raw materials a person or population consumes and 21), “smart” urban design (Chapter 13), and other forms of
to dispose of or recycle the waste produced. Individuals from sustainable development. This way, the rapid industrialization
affluent societies leave considerably larger per capita eco- of China, India, and other populous nations can occur with far
logical footprints (see Figure 1.12, p. 32). In this sense, the less environmental impact than that which accompanied the
addition of one American to the world has as much environ- industrialization of developed nations.
mental impact as the addition of 3.4 Chinese, 8 Indians, or 14
Afghans. This fact reminds us that the “population problem” HIV/AIDS is exerting major impacts
does not lie solely with the developing world, but is relevant on African populations (b) A family living in India
to people everywhere.
Indeed, just as population is rising, so is consumption, The rising material wealth and falling fertility rates of many
and some environmental scientists have calculated that we are developed nations today is slowing population growth in
already living beyond the planet’s means to support us sus- accord with the demographic transition model. However,
tainably. One recent analysis concludes that humanity’s global nations where the human immunodeficiency virus (HIV) and
ecological footprint surpassed Earth’s capacity to support us in acquired immunodeficiency syndrome (AIDS) has taken hold
1971 and that our species is now living 50% beyond its means are not following Notestein’s script. Instead, in these countries
(Figure 8.23). This is our overshoot (see Figure 1.4, p. 23). In death rates have increased, presenting a scenario more akin to
this analysis, our ecological footprint can be compared to the Malthus’s fears.
amount of biologically productive land and sea available to The AIDS epidemic (Figure 8.25) is having the greatest
us—an amount termed biocapacity. For any given area, if the impact on human populations of any communicable disease
footprint is greater than the biocapacity, there is an “ecological since the Black Death killed roughly one-third of Europe’s
deficit.” If the footprint is less than the biocapacity, there is an population in the 14th century and since smallpox and other
“ecological reserve.” Because our footprint exceeds our bioca- diseases brought by Europeans to the New World wiped out
pacity by 50% worldwide, we are running a global ecological likely millions of Native Americans.
deficit, gradually draining our planet of its natural capital and Africa is being hit hardest. Of the world’s 34 million
its long-term ability to support our civilization. people infected with HIV/AIDS as of 2012, two-thirds live in
The richest one-fifth of the world’s people possesses over sub-Saharan Africa. Because HIV is spread by the exchange
80 times the income of the poorest one-fifth (Figure 8.24). The of bodily fluids during sexual contact, the low rate of con-
226 richest one-fifth also uses 86% of the world’s resources. That traceptive use that contributes to this region’s high TFR also

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