SUSTAINABILITY AND THE
BIOSPHERIC LIFE SUPPORT
SYSTEM
John Cairns, Jr.
University Distinguished Professor of Environmental Biology Emeritus
Department of Biological Sciences
Virginia Polytechnic Institute and State University
Blacksburg, Virginia 24061, U.S.A.
April 2010
ANY OF THE FOLLOWING CRISES WILL PROBABLY
CAUSE IRREVERSIBLE DAMAGE TO BIOSPHERIC
HEALTH IF PRESENT, UNSUSTAINABLE TRENDS
CONTINUE.
1. Global climate change
2. Exponential human population growth
3. Biodiversity loss
4. Ecological overshoot
5. Ubiquitous hazardous chemicals
6. Loss of habitat
1. DESPITE THE MASSIVE INCREASE OF SCIENTIFIC EVIDENCE
THAT ANTHROPOGENIC GREENHOUSE GAS EMISSIONS
CONTRIBUTE SIGNIFICANTLY TO GLOBAL WARMING AND OTHER
TYPES OF CLIMATE CHANGE, SKEPTICISM ABOUT ITS VALIDITY IS
INCREASING.1
 A poll of 1,001 British adults found that 25% do not think global warming
is happening.
 Substantial evidence indicates a crusade to deny global warming.2
 The real “battle” is between scientists and public relations firms (not
think tanks like RAND that work on policy) representing special interests.
The latter do not dwell on whether what they are doing is ethical or
verifiable. Scientists rely on both, although sometimes their research
does not nurture the biosphere or humankind (e.g., nuclear bombs and
biological warfare).
 The biosphere will suffer from rapid global climate change because
species that cannot adapt will become extinct. Since species are the
components of the biosphere, the effects will be drastic, especially if the
rate of change increases.
2. EXPONENTIAL HUMAN POPULATION GROWTH ON
A FINITE PLANET WILL DECREASE RESOURCES AND
HABITAT FOR OTHER SPECIES IN THE BIOSPHERE.
 On a finite planet with finite resources, any form of exponential growth
is unsustainable.
 More humans on a finite planet means fewer resources per capita and
more displacement of other species from their habitats.
 The worst-case scenario is that continued exponential population growth
will destabilize the biosphere.
 Population control arouses violent emotions in religions, ethnic groups,
and most individuals.
 Of course, Mother Nature (i.e., natural laws) will keep human population
size within Earth’s carrying capacity, but the means – starvation, disease,
death – are not attractive to most people.
3. BIODIVERSITY LOSS (BIOTIC IMPOVERISHMENT) IS
PROCEEDING AT A RATE UNPRECEDENTED IN HUMAN
HISTORY.
 Species are the basic operational components of the biosphere, and
excessive loss of them will cause disequilibrium.
 After each of the five great extinctions, a diverse array of species appeared in
evolutionary time.
 Most species cannot move rapidly from an unfavorable habitat to one that is
more favorable.
 Tipping points for the biosphere are unknown but, if passed, will cause major
irreversible damage and probably result in a new, quite different biosphere.
 The performance of a new biosphere is unpredictable, but it is unlikely to be
as favorable to Homo sapiens as the present biosphere.
 Humans can have major effects on the biosphere, and the biosphere can
have major effects upon human health and well being.
4. ECOLOGICAL OVERSHOOT HAS RESULTED IN USING
APPROXIMATELY 40% MORE RESOURCES THAN EARTH
CAN REGENERATE ANNUALLY.
 If ecological overshoot were not so huge, humankind could possibly stay
within Earth’s carrying capacity, but not when the excess is so large and the
human population is growing exponentially.
 With an estimated 1.2 billion people going to bed hungry nightly and over 1
billion malnourished, any attempt at a major reduction in resource
consumption will be very difficult.
 Another major, probable difficulty in decreasing ecological overshoot is a
reduction in agricultural productivity due to climate change.
 Decreased water supply for both agricultural and human use is already
occurring.
 Major problems on climate change with carbon dioxide emissions from
burning fossil fuels may result in passing one or more ecological or social
tipping points.
5. HAZARDOUS, PERSISTENT CHEMICALS (E.G.,
ENDOCRINE DISRUPTORS) ARE HAVING DELETERIOUS
EFFECTS UPON BIOSPHERIC SPECIES, INCLUDING
HOMO SAPIENS.
 Of course, all hazardous substances are a matter of concern, but ones
that are persistent are more prone to affect a large part of the biosphere.
 Since humans have only one planet, ecotoxicity tests must be carried out
in micro- and mesocosms to simulate large-scale global effects of toxic
substances.
 All test systems have problems of scale, which is why monitoring
biospheric health is essential.
 Expanding ecotoxicology tests and procedures to protect the biospheric
life support system is a formidable but essential goal.
6. THE HABITAT AVAILABLE TO THE BIOSPHERE AND
THE SPECIES THAT INHABIT IT HAS BEEN SHRINKING
RAPIDLY SINCE THE AGRICULTURAL REVOLUTION
BEGAN OVER 10,000 YEARS AGO (E.G.,
DESERTIFICATION, SHOPPING MALLS).
 Habitat loss is a major factor in the decline of migratory species.
 Fragmentation of habitats makes the deleterious effects of habitat loss
even greater.
 Ecological restoration can partly offset habitat loss if it is carried off
promptly and in the context of the species that occupies the lost habitat.
EVOLUTION AND NATURAL SELECTION HAVE
PREPARED HOMO SAPIENS FOR IMMEDIATE CRISES
BUT NOT FOR
LONG-TERM GLOBAL CRISES.
 Most people take the biospheric life support system for granted since
they have never experienced any other system.
 Earth’s present atmosphere, which affects Earth’s climate, differs from
past ones because the present life forms differ from those of the past.
THE QUEST FOR SUSTAINABLE USE OF THE PLANET REQUIRES
ROBUST SCIENTIFIC EVIDENCE ON A CONTINUAL BASIS, WHICH
WILL REQUIRE THE PUBLIC AND ITS POLITICAL
REPRESENTATIVES TO LET THE SCIENTIFIC PROCESS RUN ITS
USUAL COURSE WITHIN THE COMMUNITY OF QUALIFIED,
CREDENTIALED SCIENTISTS.
 Numerous attempts by some special interest groups, often represented
by individuals with minimal scientific credentials, disrupt the scientific
process and reduce public faith in science.3
 Scientific evidence and analyses are best discussed in peer-reviewed
journals by scientists within the field being evaluated.
 Public confidence in science is reduced and much time is wasted by news
media and scientists on disinformation.
NO INDIVIDUAL OR NATION CAN ESCAPE THE
EFFECTS OF RUNAWAY CLIMATE CHANGE IF IT
OCCURS.
 The interactive crises are global (e.g., climate, population, biodiversity,
ecological overshoot, hazardous chemicals, loss of habitat).
 Global crises must be met by everyone or civilization will end.
 A remnant of Homo sapiens might survive a global catastrophe, but
civilization as presently known probably will not.
 No one can say of distant lands and peoples: “Their area of Spaceship
Earth is in trouble, but that situation has nothing to do with me.”
 When snow is on the ground, any belief in global warming is markedly
decreased.
HUMANS MAY BE MORE INTELLIGENT THAN OTHER
SPECIES, BUT THEY HAVE USED THEIR INTELLIGENCE
TO DEVELOP NEW TECHNOLOGIES THAT HAVE
ENABLED THEM TO DEPLETE RESOURCES MORE
RAPIDLY THAN IN THE PAST.
 The biospheric life support system has kept Earth habitable for humans.
 The exhaustion of resources creates new crises that require new
technologies.
 Technologies have also enabled exponential population increase that
exacerbates resource depletion problems.
 The biospheric life support system is the source of all renewable
resources upon which the human economy is dependent.
CAN HUMANKIND USE ITS INTELLIGENCE TO LIVE
SUSTAINABILY INSTEAD OF USING RESOURCES AT AN
UNSUSTAINABLE RATE?
 Living sustainably would require social goals that give intergenerational
equity a very high priority.
 Living sustainably requires both stable ecosystems and stable social
systems.
 Living sustainably requires a superb long-term perspective – something
in which humankind has not excelled.
 The best legacy the present generation could leave its children is a
habitable planet.
GLOBAL CLIMATE CHANGE AND DEPLETION OF
RESOURCES WILL MAKE MANY AREAS OF THE PLANET
LESS SUITABLE FOR HUMANS, WHICH WILL MARKEDLY
INCREASE THE NUMBER OF ENVIRONMENTAL
REFUGEES.
 Environmental refugees will probably be a major problem.
 If existing resources are shared with refugees, the per capita resources
will drop dramatically if the number of refugees is large.
 The few, remaining, relatively normal ecosystems may be used by
refugees as a campground and the local forests for firewood.
 The probability of refugees returning to their original home is small
because large-scale problems cannot be quickly corrected and may even
be irreversible.
A HEALTHY BIOSPHERE IS
ESSENTIAL FOR SUSTAINABLE
USE OF THE PLANET BY
HOMO SAPIENS.
NO INDIVIDUAL OR NATION
CAN ESCAPE THE DELETERIOUS
EFFECTS OF RUNAWAY CLIMATE
CHANGE.
Acknowledgments. I am indebted to Darla Donald for transcribing the
handwritten draft and for editorial assistance in preparation for publication
and to Valerie Sutherland for converting it to Power Point.
References
1BBC
News. 2010. Climate skepticism ‘on the rise,’ BBC poll shows. 7 Feb
http://news.bbc.co.uk/2/hi/8500443.stm.
2Hoggan, J. 2009. Climate Cover-up: The Crusade to Deny Global Warming.
Greystone Books, Vancouver, Canada.
3Rosenthal, E. 2010. Skeptics find fault with U.N. climate panel. New York
Times 8 Feb
http://www.nytimes.com/2010/02/09/science/earth/09climate.html.