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11 March 2002
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On Biodiversity, Climate change and Sustainability (3)By Jeff Harvey1Ferdinand Engelbeen2 wrote: "As already sent to the list, I was completely wrong about Biosphere II, they failed mostly because they underestimated the amount of CO2 generated by bacteria in the too large amounts of raw compost. Thus we still have much to learn about what happens in complete ecosystems... This is only one of hundreds of reasons Biosphere 2 failed (see below). What annoys me about cornucopians is that they somehow think that we can somehow effectively manage ecological systems exhibiting unimaginable complexity, in the face of the myriad of ways we are assaulting these systems at present. They base this optimism on not a shred of scientific evidence, but instead cling to the mirage that human ingenuity will devise technologies that will forestall all of the deleterious effects we are having on our life-support systems. Speaking as an ecologist, I can assure you that we are working against time to better understand how these systems evolve, assemble and function, particularly under conditions of human-induced simplification. What I can say is that emergent properties, such as ecosystem productivity and resilience, are generated over large spatial and temporal scales by the aggregated biological activities of interacting organisms operating at small scales. Working up to even larger scales, we are trying to bridge micro-evolutionary processes with macro-evolutionary processes, even to the point which includes the regulation of biogeochemical and hydrological cycles. But complex adaptive systems, as ecologist Simon Levin refers to the biosphere, are so immensely complex that we have barely begun to understand the spatial component. Furthermore, in bridging the scaling chasm we need to understand how the complex biosphere has emerged from natural selection and other forces operating at small scales, and the degree to which the evolutionary process operates to maintain this critical support system. The answer is that we have only made small headway to untangling ecological complexity. So I can't deny that I get annoyed when someone with no grounding in the field makes the kind of simplistic observation that Mr. Engelbeen made above. In Biosphere 2, just about everything went wrong. Here is a good overview from an article in Atlantic Monthly (12/97) by Ehrlich et al: The idea that technology can fully substitute for natural life-support systems recently underwent a damning test in the first Bisophere 2 "mission." Eight people moved into a 3.15-acre closed ecosystem, intending to stay for two years. The $200-million-plus habitat featured agricultural land, "wetlands," "rain forest," "desert," "savanna," and even a mini-ocean with coral reefs. A sample of biodiversity thought adequate to keep the system functioning was included, and the system was designed to supply the "biospherians" with all basic material needs and more. But comfort was short-lived, and the experiment ended early in failure: atmospheric oxygen concentration had dropped to 14 percent (a level typical of elevations of 17,500 feet); carbon dioxide spiked erratically; nitrous-oxide concentrations rose to levels that can impair brain function; nineteen of twenty-five vertebrate species went extinct; all pollinators went extinct, thereby dooming to eventual extinction most of the plant species; aggressive vines and algal mats overgrew other vegetation and polluted the water; crazy ants, cockroaches, and katydids ran rampant. Not even heroic efforts on the part of the system's desperate inhabitants could suffice to make the system viable. What went wrong? Evidently more was involved than aesthetic or moral arguments for having the right components of nature in the closed system of Biosphere 2. This is also true in the closed system of the earth as a whole. The biospherians learned a basic lesson the hard way: humanity derives a wide array of crucial economic and life-support benefits from biodiversity and the natural ecosystems in which it exists. Many of these benefits are captured in the term "ecosystem services," which refers to the wide range of conditions and processes through which natural ecosystems, and the species that are a part of them, sustain and fulfill human life. These services yield ecosystem goods, such as seafood, wild game, forage, timber, biomass fuels, and natural fibers. They also underpin agricultural productivity, the pharmaceutical industry (nine of the top ten pharmaceuticals in the United States are derived from natural sources), and many other aspects of industrial production. Natural ecosystems perform critical life-support services that make consumption possible and upon which the prosperity of all societies depends. These include the purification of air and water; the mitigation of droughts and floods; the generation and preservation of soils and renewal of their fertility; the detoxification and decomposition of wastes; the pollination of crops and natural vegetation; control of the vast majority of potential agricultural pests; and partial control of climate. This array of services is generated by a complex interplay of natural cycles powered by solar energy and operating across a wide range of space and time scales. These services operate on such a grand scale, and in such intricate and little-explored ways, that most of them could not be replaced by technology -- even if no expense were spared, as Biosphere 2 showed. Ecosystem services are worth trillions of dollars annually, but since they are not traded in economic markets, they do not carry prices. If they did, changes in those prices might serve to alert society to reductions in their supply or to deterioration of the underlying ecological systems that generate them. Moreover, humanity came into being after the underlying systems had been in operation for hundreds of millions to billions of years. Thus it is easy to take ecosystem services for granted and hard to imagine their disruption beyond repair. No one knows precisely which, or approximately how many, species are required to sustain human life; but to say, as Sagoff does, that "there is no credible argument ... that ... all or even most of the species we are concerned to protect are essential to the functioning of the ecological systems on which we depend" is dangerously absurd. Until science can say which species are essential in the long term, we exterminate any at our peril. Shaheed Naeem, a leading ecologist who has been working on the biodiversity/ecosystem functioning area for a number of years, was asked for his opinion on how to make Biosphere 2 viable. His answer? "Burn the whole thing down, and let the system build itself up from scratch". This may sound like a rash observation but it perfectly encapsulates what we ecologists know: that using current knowledge, we cannot replicate a self-perpetrating, stable and viable ecosystem, and that we won't have this "knowledge" in the near future, either. Jeff Harvey Transcribed from a contribution to Ecological Economics 11 March 2002. Footnotes by ecoglobe: 1 Dr. Jeffrey A. Harvey is Senior Scientist at the Netherlands Institute of Ecology, Centre for Terrestrial Ecology, Boterhoeksestraat 48, NL-6666 Heteren, The Netherlands. Tel: (+31) (26) 4791 306 2 See ecological economics discussion records at csf.colorado.edu [Link opens in a new window.] ** This material is distributed for research and educational purposes only. ** email feedback to<welcome@ecoglobe.org.nz> - on-line feedback |
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11 March 2002
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