Our Gift to Posterity
A sermon delivered at the Unitarian Universalist Congregation (Blacksburg Virginia), July 31, 2005,
by John Cairns, Jr., a long-time UUC member and Virginia
Tech University Distinguished Professor of Environmental Biology
is rumored to have said that all literature is about loss—a
concept I struggle with and wanted to reject upon first
hearing—preferring to write out of joy—indeed ideally out
of exaltation bearing witness to the things I love during this brief
life—it took me a while to realize that even the act of
celebrating is an acknowledgment of loss for it is the temporal
nature of celebration—the awareness that a thing has not always
been one certain way before, and may not always be thereafter—which
most sharpens the poet’s and the reader’s senses.
Celebration and loss are shadows of one another in literature.
Rich Bass, The Space Between
lesson from the five great global extinctions is that species and
ecosystems come and go, but the evolutionary process continues. In
short, life forms have a future on Earth, but humankind’s
future depends on its stewardship of ecosystems that favor Homo
John Cairns, Jr., Future of Life on Earth
My purpose this morning
is to persuade you that global environmental catastrophes are the
result of the cumulative impact of small, individual decisions, which
are threatening the future of our children, grandchildren, and
1948, my mentor Ruth Patrick selected the concept of “use
without abuse of the planet” as a major goal of her work.
Currently, this goal is described by the word sustainability.
Eco-ethics is the essential foundation for sustainable use of the
planet. E. O. Wilson remarks: “in the end, however, success
or failure will come down to an ethical decision, one on which those
now living will be defined and judged for all generations to come.”
Sustainability is a utopian vision that requires living harmoniously
with nature, which will exact harsh penalties on species that exceed
Earth’s capacity and violate nature’s laws.
Sustainability attempts to combine a homocentric with an ecocentric
Temporal and Spatial Scales
Earth has existed for
about 4½ billion years and has an estimated 15 billion years
left. Humans have existed for a mere 160,000. Species survival
spans vary from a few years to 40 million years (for one species of
marine ostracod). Collapses of the civilizations in the past have
been regional and, with humans low in numbers and spread thinly over
the planet, the effects did not spread widely. Globalization has
made societal collapse likely to have global effects. Exponential
growth of the human population and continued excess resource
consumption increases the probability of a global collapse.
The Biospheric Life Support System
The biospheric life
support system consists of natural capital and the ecosystem services
it provides. Natural capital consists of natural resources,
including living organisms. Ecosystem services include:
maintenance of breathable air
capture of solar energy and conversion into biomass
control of both
microclimate and macroclimate
maintenance of soils
An economy needs four
types of capital to function properly:
capital—labor, intelligence, culture, organization
capital—cash, investments and monetary instruments
ecological footprint is a measure of the “load” imposed
by a given population on nature. The best way to approach the
ethical issues involving humankind and Earth’s resources is the
calculation of an individual ecological footprint. My favorite
calculation can be found on line at myfootprint.org. The
global average of an individual ecological footprint is 1.7
biologically productive hectares per human.
(See this Web site)
If present growth rates continue, the biologically productive space
will drop to 1.0 hectares per person once the population reaches its
predicted 10 billion in just over 30 years. The United States now
has an ecological overshoot of 3.6 hectares per capita.
12% of Earth’s ecological capacity is set aside as preserved
for the over 30 million species that constitute the biospheric life
support system. This area is almost certainly not enough. Global
warming and the acidification of the planet’s oceans will
probably have major deleterious impacts upon the biospheric life
1960, the ecological footprint of humankind required only 0.7 planet
Earths. In 1980, it required only 1.0 planet Earth. In 2000, it
required 1.2 Earths and continues to rise. If global warming and
acidification of the world’s oceans place the biospheric life
support system in disequilibrium, the planet’s carrying
capacity will be dramatically reduced. This situation would not be
good for either posterity or us.
The Case for Optimism
a southern state in India, has a per capita income of US$1.00/day
(about one sixtieth of North American incomes). However, the life
expectancy, infant mortality, and literacy rates there are similar to
those of industrialized countries. A major difference is that Kerala
emphasizes social capital while the United States emphasizes
Success or Failure
can get insights into the fate of humankind from small island
biogeography. Tikopia Island inhabitants lived sustainably for over
3,000 years. A translation of a native expression shows that a
community of interest and kinship is important. The Tikopia are
“primitive” Polynesians without much interest in present
day technology (Firth, 1983). Firth’s sociological study
describes in detail some of the measures they used, even though the
methods will be repugnant to many persons now alive. However, when
compared to the fate of the people of Easter Island (Rapa Nui), the
consequences were less catastrophic. Rapa Nui provides a classic
study of societal collapse caused by excessive anthropogenic
transformation of the island’s ecological life support system.
The population of Rapa Nui went from under an estimated 2,000 in 400
AD to approximately 10,000 around 1600 AD (Kirch, 2000). The numbers
then plunged precipitously to well under 2,000 and returned to 2,000
about 2000 AD, but carrying capacity of the island had been severely
reduced (on-line literature on this contrast is available:
“Sustainability Ethics: Tales of Two Cultures”; “Ecological
Overshoot and Ecological Restoration”;
“You and the Earth’s Resources”). Diamond (2005)
lists five causes for failure of civilizations: deeply held
religious beliefs, failure to anticipate, failure to perceive a
problem, rational bad behavior, disastrous values.
danger to humankind from the worsening ecological overshoot makes the
reevaluation of our values mandatory. Many people are repelled by
the means taken to stabilize the human population on a finite space
with finite resources (Tikopia). However, does the precipitous loss
of 8,000 people out of 10,000 (disease, famine, cannibalism, and
homicide) on Easter Island disturb you even more? A few illustrative
Is respect for the
interdependent web of life (the biospheric life support system)
Do we have
sustainable balance of homocentric views with ecocentric views?
What percentage of
Earth should be primarily reserved for naturalistic,
self-maintaining ecosystems? At present, it is 12% globally, and
the percentage continues to fall. The addition of 3-4 billion
people in the next 30 years will make the decision even more
difficult. Do you favor more or less than 12%? Try to pick your
What changes in
behavior are you prepared to initiate to make sustainable use of the
plant more probable?
If you had to
choose between living on Tikopia any time in the last 3000+ years or
Easter Island during the ecological overshoot period, which one
would you choose? Why?
On a highly
urbanized planet, how might humankind develop a mutualistic
relationship with natural systems?
if humankind fails to address the ecological overshoot issue
effectively, nature will resolve the issue as many societies
suffering ecological collapse have discovered.
Diamond, J. 2005.
Collapse: How Societies Choose to Fail or Succeed. Penguin
Group, New York.
Firth, R. 1983. We,
The Tikopia. Stanford University Press, Stanford, California.
Kirch, P. V. 2000. On
the Road of the Winds. University of California Press, Berkeley,
Copyright 2005, John Cairns, Jr.; Commercial Duplication Prohibited
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