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Reflections OR the Second World Climate Conference Victor D. Phillips HawaiiNaturalEnewlnstitute OfHawaii at Manoo Honolulu, HI 96822
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Geneva, November 3,1990 Deep-sea sediments reveal that a natural cycle of planetary cooling and heating (icing and de-icing) occurs as the Earth’s orbit around the s u n fluctuates, and ice core data show that a corresponding natural cycle of low and high CO, concentrations also occurs (11. Apparently, changes in climate and carbon flux are closely linked and are normal, homeostatic responses by Spaceship Earth on her voyage through space. If global warming via the greenhouse effect is an integral component of the routine operation of our home planet, why is there such alarm? Is this an “infrared herring?’’ The reason for alarm is that climate models predict that the Earth’s temperature will exceed any peak value of the natural cycle within a decade or two because of exponential increases in greenhouse gas concentrations from human activi“es. The phenomenal increase of irbon dioxide, chlorofluorocar, o m , m e t h a n e , n i t r o u s oxide, ozone, and other infrared-absorbing gases is largely caused by the combustion of fossil fuels that followed the Industrial Revolution, the destruction of forests at the hands of a burgeoning human population, and the use of various synthetic chemicals in industry and agriculture. Not only will humans experience the
highest temperature since the dawn of civilization, but the rate of temperatwe change (on a time scale of decades rather than millenia) may leave little time to adapt or to implement solutions. Oceanoerauher Wallace Broecker (21 eloqu&tfy describes the potential greenhouse effect crisis as follows: “The inhabitants of planet Earth are quietly conducting a gigantic environmental experiment. So vast and so sweeping will be the consequences that, were it brought before any responsible council for approval, it would be firmly rejected. Yet it goes on with little interference from any jurisdiction or nation. . . . While the international scientific debate over global warming continues, most national leaders are wisely seeking viable remedial actions to turn down the thermostat or are identifying adaptive measures to cope with a changing environment. As is the case with all ecological problems, global warming is the result of many interconnected actions reaching far into all human endeavors: politics, economics, agriculture, energy use, life-style, and population growth. The solution will be found through improved understanding of the interaction between three fundamental systems: nature (ecosystems), technology (production systems), and political economy (economic systems) (3). This paper offers suggestions for basic research that needs to be completed to fill critical gaps in scientific knowledge of global warming and presents some basic concepts of the ’I
0013-936X/91/0925-574$02.50/00 1991 American Chemical Society
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relationship between green plants and climate control, using oceanic phytoplankton, tropical forests, and boreal forests as examples. Also discussed is the potential role of green plants in the remediation of global warming through (1)policy changes addressing deforestation, acid rain, sustainable farming practices, and reforestation, and (2) technical fixes involving plant migrations, plant breeding, and fertilizing the open oceans. Although the measures presented here can provide temporary assistance, a remedial course in human ecology may be the ultimate solution to our survival and quality of life. Critical gaps in knowledge The general climate models that predict an increase in the average surface temperature of 2-5 OC by as soon as the year 2030 are based almost exclusively on physical and chemical data from the atmosphere. They are largely devoid of pertinent information from the oceans and biosphere, and thus are incomplete. The models could more accurately predict rates of warming as well as regional differences and impacts by including oceanic and biotic data. Due to lack of funding (only around $30 million is spent on greenhouse effect research each year worldwide) (41, critical gaps in scientific knowledge exist. These gaps lead to scientific controversies, which will only be resolved when the data are available. Some of the unresolved problems are an inability to balance the global carbon budget, the magnitude of the oceanic sink for uptake of greenhouse gases, whether tropical forest areas are a carbon sink (via CO, fertilization) or source (via increased respiration rates and deforestation), the rate of global warming, and the regional differences and impacts. The most important basic research needed to fill these gaps includes oceanic surfaceatmosphere flux rates; oceanic surface-deep water flux rates: the role of marine phytoplankton in CO, uptake: rates of deforestation: and rates of terrestrial ecosystem-atmosphere flux, especially tropical forests and agricultural crops. Specifically, surfacebased oceanic and terrestrial biome stations, similar to the meteorological stations established as a result of the 1957 International Geophysical Year, are needed to provide oceanic and biotic data to accompany the excellent climatic data now available. To highlight the value of such
stations, recall that continuous 1 measurement of CO, concentrations over the past 30 years at Mauna Loa, Hawaii, has provided the definitive data to determine the current rate of increase, and polar ice cores collected at various stations sponsored by different nations have provided the best and most complete record of CO, concentrations back to 160,000 years ago. Space-based remote sensing via satellites provides information on cloud cover and dynamics, oceanic circulation patterns, magnitude and rates of deforestation, and primary productivity of marine plankton and terrestrial plants (5, 6). Satellite-derived data must be verified on the surface,initially (a costly and time-consuming task) to confirm space-based estimates. Absolute values a n d flux rates between sources and sinks of all greenhouse gases need to be determined (CO, contributes to only half of the projected global warming). Perhaps much of this work could be initiated through the International Year of the Greenhouse Effect 1991, proposed by Representative Bill Green of New York and Senator A1 Gore of Tennessee, via the International Council of Scientific Unions’ “International Geosphere-Biosphere Program-A S t u d y of G l o b a l Change” and the World Meteorological Organization-U.N. Environment Programme’s “World Climate Research Program.” Green plants and climate control Biological control of the Earth’s climate is evident through recent studies of oceanic phytoplankton, tropical forests, and boreal forests. Oceanic phytoplankton. Oceanic phytoplankton may regulate the Earth’s temperature in two ways. One mechanism involves the removal of CO, from the atmosphere via photosynthesis, especially during spring and summer blooms when water temperature, sunlight, andlor nutrients increase. Subsequently, a “rain” of planktonic skeletons containing calcium carbonate (CaCO,) and organic carbon compounds falls from the surface to the ocean floor. This transfer of carbon from the atmosphere to marine sediments via marine algae cools the planet. A comparison of data from polar ice cores and deep-sea cores indicates that variations in CO, concentration and climate are essentially the same (7). The second mechanism of planktonic climate control relates to the
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production of a metabolic waste product, dimethyl sulfide (DMS). An increase in surface water temperature results in greater phytoplankton productivity. More phytop l a n k t o n p r o d u c e m o r e DMS released to the atmosphere. The DMS aerosol provides condensation nuclei, allowing clouds to form over remote oceans. The clouds increase the Earth’s albedo, which in turn cools the surface water and decreases phytoplankton populations and subsequent production of DMS. Deep-sea sediments reveal that a catastrophic decline (90%) of oceanic phytoplankton occurred 65 million years ago when massive extinctions of life forms, including the dinosaurs, took place, and probably resulted in a 10 “C warming of the Earth (8). Tropical forests. The tropical forests are a global pump which moves warm, moist air from equatorial to temperate regions. As much as 75% of the rain falling on moist tropical forests is returned to the atmosphere through direct evaporation and evapotranspiration, having a considerable cooling effect in tropical areas (9). Trade winds deliver the warm, moist air to higher latitudes, and upon precipitation, the latent heat of vaporization is released to warm the temperate zone. In addition to this vital role in the global water cycle, the tropical atmosphere generates hydroxyl radicals, which are effective in removing many trace greenhouse gases from the atmosphere (9). In terms of the global carbon cycle, tropical forests and soils contain approximately half of the total organic carbon on Earth (20). This vast tropical terrestrial carbon reservoir remained relatively constant, with photosynthetic carbon uptake equaling respiratory carbon release (P = R), until humans began clearing the forests. As the human population continues to grow exponentially, the destruction of the forests has accelerated and has resulted in an increasing release of carbon to the atmosphere (P < R). Current estimates of the net carbon flux from the tropical forests and soils to the atmosphere are about 1 x g carbon per year, compared to apg carbon per proximately 5 x year from the combustion of fossil fuels. Of this total carbon release of 6x g carbon per year, increasing CO, concentrations in the atmosphere at + 1.5 ppm annually can account for 3 x g carbon or approximately half ( 2 2 ) . The other 576
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half enters carbon sinks i n the oceans and other regions of the biosphere. Boreal forests. To illustrate the influence of boreal forests on the Earth’s climate, it is first important to note the dominance of the seasonal growth cycle, such that CO, uptake is highest during the summer growing season and lowest during the winter. Tree rings provide a record of growth activity. It has been demonstrated that the rate at which CO, is removed from the atmosphere is positively correlated with variations in tree-ring chronologies, which suggests that recent increases in CO, amplitudes may have been caused partially by seasonally enhanced growth of the boreal forests (12). Whether this growth is the result of CO, fertilization or other environmental factors remains unresolved at this time. In fact, Woodwell (23) testified that as temperature increases, rates of respiration increase without producing a n equivalent change in rates of photosynthesis. This has the effect of releasing more carbon to the atmosphere. Woodwell also challenged the belief that any forest growth has occurred recently, and suggested that most data indicate that forests have declined over recent decades.
Role of green plants The remediation of global warming via green plants can proceed on two routes: policy changes that prevent further destruction of natural ecosystems and that promote the restoration of degraded ecosystems, and technical fixes that enable threatened plants to survive and that can help plants alleviate the dramatic climate changes now occurring. We humans and all other life forms on the planet can greatly benefit from the emergency assistance provided by green plants to help control global warming, but until we recognize that our existence, maintenance, and civilization are only possible in a functional biosphere and act accordingly, these remedial actions will be tem-, porary treatments of symptoms, and our life-support system will continue to deteriorate. Policy changes. The most urgent policy change is to stop deforestation. Although the rates of global deforestation are uncertain (most estimates are approximately 30 million hectares per year) [ Z O ) , the release of CO, as a result of this destruction is greater than the uptake of GO, by terrestrial plants ( 2 4 ) .
This leads to the paradoxical result that tropical forest regions are a carbon source and not a carbon sink. In effect, we are literally “putting more logs on the fire” of global warming. We are systematically sacrificing the most vital component of our global air conditioning system at a time when we need it the most. We must replace this careless destruction with careful stewardship. Encouragingly, a policy change to help protect Amazonian rain forests has been implemented recently in Brazil. Another careless treatment of the world’s forests involves their exposure to acid rain and other toxic air pollutants (1 5 ) . This physiological burden imposed on t h e forests weakens them and limits their ability to respond to common stresses and to perform routine ecological functions. The extra duty of detoxifying our waste products and ameliorating the climate may be overwhelming. This chemical onslaught may alter plant life cycles, resulting in early senescence and death, and thus contributes to additional CO, build-up and global greenhouse warming. A healthy forest can provide essential ecosystem services such as fresh water, clean air, and fertile soil. Increased energy conservation and improved energy efficiency will result in a lighter load of toxins for the forests to process. A switch to renewable energy and a return to natural products, instead of synthetic ones, would be beneficial. The enforcement of stronger policies that protect the biosphere from poisoning are needed. Another policy change involves more intensive and sustainable farming practices. Permaculture (“permanent” + “agriculture”), organic farming, and agroforestry are all attempts to restore vitality and long-term productivity to croplands and to provide multiple farm products on a sustainable basis. This intensive care emphasizes biological control of pests: fertilizing with crop residues, animal wastes, and legumes: and minimum tillage. The crop yields from these alternative farming practices often exceed yields from farms heavily subsidized with petrochemicals (2 6). By engaging in permaculture, we largely avoid “eating oil,” which decreases CO, emissions to the atmosphere. I spell relief from global warming: “R-E-L-E-A-F.”An aggressive reforestation campaign similar to the Ci-
vilian Conservation Corps program i m p l e m e n t e d b y F r a n k l i n D. Roosevelt is needed to expand the total area of forests worldwide. This extensive care program will have the extra benefits of improving watersheds and water quality, preventing soil erosion and flooding, and providing jobs, in addition to helping reduce global warming. The selection of tree species for successful establishment in changed climatic conditions of different regions is crucial. Technical fixes. The most important of the technical fixes that will assist green plants in responding favorably to a changing climate is the preservation of plant species (with their “green blueprints” of DNA). Because trees cannot travel quickly enough to cope with the dramatic climate changes that are forecast, especially at high latitudes (1 3). human-assisted migrations of plant propagules to suitable regions for survival would be money well spent. This could be another job for the RELEAF Project. An aggressive plant breeding program to help protect economically important plants such as agricultural crops, medicinal plants, and trees for fuelwood and lumber would be worthwhile. By developing genetic strains exhibiting tolerance to beat, drought, and salt stresses, as well as resistance to pathogens and pests, the potential impacts to agriculture and forestry could be minimized. In C, plants (e.g., wheat and rice), as much as half of the photosynthetically fixed carbon may be reoxidized to CO, during photorespiration (171, w h i c h decreases net photosynthetic efficiency and contributes to global warming. Efforts to breed for low rates of photorespiration in C, crop plants are wmanted. Also, by selecting and cloning individual plants that exhibit superior growth, total yield per unit area can be increased and more carbon can be captured. In Hawaii, highyielding Brazilian clones of eucalyptus and giant leucaena from Mexico demonstrate the potential for genetic improvement [these trees are candidates for producing methanol or ethanol from biomass feedstocks to replace imported oil). Another genetic improvement would be to decrease the amount of carbon compounds extruded by roots, which is returned as CO, to the atmosphere via bacterial metabolism. As much as 40% of all photosynthate is lost through the roots of many grain crops in this process of
rhizodeposition (1 8). At increased temperatures, most plants respond physiologically such that the rate of respiration exceeds the rate of pho- I tosynthesis, thus aggravating the greenhouse effect problem (13). It would be desirable to genetically induce plants to stimulate photosynthetic reactions and depress respiratory pathways at higher heat , loads. As a final example, some d plants manufacture insoluble calcium oxalate crystals as excretory products (19). By enhancing this ability to “grow rocks,” living “pet- 4 rified forests” could remove carbon from the atmosphere and bury it underground, provided that the crys- , tals remain insoluble and unavailable as food for microbes. Aside from preventing global deforestation, perhaps the next most potentially promising remedial action via green plants involves marine algae, or phytoplankton. Generally, the open oceans are characterized as “wet deserts,” that is, having low net primary production levels similar to those of arid deserts. The reason for this low productivity has been attributed to a lack of nitrogen (201.Recent evidence has revealed, however, that iron may be more limiting than nitrogen in the open oceans (21). Covering almost three-quarters of t h e p l a n e t ’ s s u r f a c e , t h e open oceans make the largest contribution to the total net primary production on Earth, followed closely by tropical forests, then temperate forests (22). With so much open ocean surface area and with so little human impact on it, the potential for blue-water solutions to the greenhouse effect is enormous. However, as we probe and manipulate the open oceans-one of the Earth’s ecosystems with which we are least familiar scientifically-it is prudent to proceed cautiously with the completion of comprehensive basic ecoloeical research and thorouh envi-
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oceans [Le., removal of carbon through deposition of CaCO, at the seabed) is greater than the release of CO, by food chain metabolism in the surface water is critical.
as we accelerate the extinction of other species and lose forever the benefits of their contributions to the life support system within the terrarium, we become endangered. Human ecology, the ultimate solution, is a remedial course in preventive care and self-preservation. As if launching this new awareness and bringing metaphor to life, a 2.5acre terrarium called "Biosphere II" has been constructed in Oracle, Arizona, by Space Biosphere Ventures, Inc. This pioneering research facility, which features seven interconnected ecosystems including a tropical rain forest and a coral reef, will be home to eight researchers sealed within its glass structure for a two-year experiment on life-support systems in 19911992. In their miniature version of Spaceship Earth, the lessons they learn about human ecology will serve as a basic curriculum guiding the rest of us passengers into the 21st century and beyond. Welcome aboard!
Human ecology The ultimate solution to this crisis will involve an international effort to think globally and a commitment by individual nation states to implement agreed-on strategies locally. The solution will have many facets depending on local ecosystems, culture, and political economy, but will have in common a fundamental change in how we humans perceive nature. The solution involves how to live within the natural limits imposed upon us by the laws of thermodynamics and ecology. The familiar litany of environmental ills has been a prelude to global warming. We are becoming increasingly alert to these warning signals and are beginning to recognize that our health and economic security are threatened. At present, we choose to treat the symptoms of environmental diseases so that business-as-usual can continue. Until we choose to tackle the cause of the problems, however, the problems will only get worse. The fundamental flaw is failing to understand not only that nature provides the resource base for all economic activity, but that this same resource base is our life-support system on the planet. A healthy, sustainable Victor D. Phillips is the manager of economy is based on a healthy envi- bioresources and e n v i r o n m e n t a l reronment. When decisions are made search a t the Hawaii Natural Energy Inin which economic considerations s t i t u t e at t h e University af Hawaiiexclude or override ecological ones, Manoa (Honolulu). He coordinates a n environmental crises such as global international effort io remediate global warming a n d h a s a Ph.D. in ecology greenhouse warming result. Immediate stop-gap measures from the University of Colorado. that treat symptoms, both technical fixes and policy changes, are none- References theless worthwhile because they (1) Gribbon. I. New Scientist 1988, limit the current rate of destruction 118(1613). 32-33. and prevent further damage. A dras- (2) Broecker. W. S. Nature 1987. 328. 123-26. tic re-education effort, which will enable us to retool our technologies (3) Commoner. B. The Poverty of Power: Energy a n d the Economic Crisis: and economies for permanence and Knopf: New York. 1976. compatibility with nature, needs to (4) Woodwell, G. M. Testimony before the be initiated in our schools as soon US.Senate Committee on Envimnment and Public Works, June 10. 1986 US. as possible. Basic concepts of popuGovernment Printing Office: Washinglation growth, life-style, resource ton. Dc,1986 Y4.P96/1OS.hrg./9%723. utilization, appropriate technology, (5) Woodwell. G. M. et al. I. Geophys. energy efficiency, conservation, Res. 1 9 8 7 , 9 2 , 2 1 5 7 4 3 . sustainable economics, and peace (6) Tucker. C. J. et al. Nature 1986. 319, need to be re-examined. 195-99. By acting as if we live in a terrari- (7) Genthon. C. et al. Nature 1987. 329, 414-18. um in the sunshine, and recognizing that there is no "away" in which (8) Rampino. M.R.; Volk. T. Nature 1988,332,6365. to dump our expanding wastes or to (9) Bunyard. P. The Ecologist 1987. 17. which we can escape when over13941. crowded, we will have begun to (101 Houghton. R. A. et al In Atmospheric Corbon Dioxid? and the Global Corbon make progress. We must realize that 578 Environ. Sci. Technol., VoI. 25. No. 4, 1991
C cle U S Department of Energy: dashiigton: Dc.1985. pp. 113-40. (11) Woodwell, G.M. Oceonus 1986, 29, 71-75. (12) D'Arrigo. R.. Jacoby. G C , Fung. I Y Noturr 1987, 328.321-23 (13) Woodwell. C M In The Nat,onol Ch.
mate Pmgmm Act and Global Climate Change Hearings, July. Sept. 1987: US. House Committee on Science. Space, and Technology: US. Government Printing Office: Washington, DC, 1987: Y4.Sci2:100-73. (141 Detwiier, R. P.; Hall, C.A.S. Science 1988,239.42-47. (151 Postel. S. Air Poilution, Acid Rain. and
the Future ofForests; Worldwatch Institute: Washingion. Dc.1984. (161 Jackson. W. New Roots for Agriculture: Friends of the Earth: San Francisco. CA,1980. (17) Raven, P. H.: Evert, R. F.: Curtis, H. The Biology of Plants, 3rd ed.: Worth New York, 1981. (18) Lynch, I. New Scientist, 1988. li8(1610),4 5 4 9 . I191 . . Zwindler-Frank. E. Z.Pnanzenohvsiol.1976.80.1-13. (20) McCarthy. J. I.: Carpenter, E.J. In N i b
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gen in the Marine Environment Carpenter, E. I.; Capone. D. G..Eds.: Academic Press: New York. 1983, pp. 487-512. (21) Martin, J. H.; Fitzwater, S. E. Nature 1988,331,34143. (22) Miller. G. T. Living in the Environ-
ment: An Introduction to Environmpntol Sciencc. 4th ed.; Wadsworth: Relmont. CA. 1985.
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