1 / 17

Sustainability and the Biospheric Life Support System

This article explores the various crises that threaten the biosphere, including global climate change, exponential human population growth, biodiversity loss, ecological overshoot, hazardous chemicals, and habitat loss. It discusses the irreversible damage these crises may cause if present unsustainable trends continue.

ileanar
Télécharger la présentation

Sustainability and the Biospheric Life Support System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. 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

  2. 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

  3. 1. DESPITE THE MASSIVE INCREASE OF SCIENTIFIC EVIDENCE THAT ANTHROPOGENIC GREENHOUSE GAS EMISSIONS CONTRIBUTE SIGNIFICANTLY TO GLOBALWARMING AND OTHER TYPES OF CLIMATECHANGE, 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. A HEALTHY BIOSPHERE IS ESSENTIAL FOR SUSTAINABLE USE OF THE PLANET BYHOMO SAPIENS.

  16. NO INDIVIDUAL OR NATION CAN ESCAPE THE DELETERIOUS EFFECTS OF RUNAWAY CLIMATE CHANGE.

  17. 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.

More Related