Lessons from the Ozone Layer

Out of the many important aspects of the ozone history, I would like to highlight five factors that appear most relevant to the climate negotiations (1) the role of science and scientists (2) the necessity for strong and consistent leadership (3) the flexible design of the Montreal Protocol (4) the technological revolution that emerged from public-private sector partnerships and (5) the involvement of developing countries in the solution. 3.1 Role of Science and Scientists Science played a...

Tortuous Targets in Kyoto

Even industrialized countries differ widely among themselves in geography, population, natural resource base, climatic conditions, industrial structure, and dependence on energy. Since these critical parameters are either intrinsic or immutable in the short run, it is extremely difficult to establish short-term emissions targets that are both economically feasible and equitable. Nevertheless, the Kyoto negotiators tried. The centerpiece of the Kyoto Protocol is the commitment by Annex I...

References

C. (1980). Summer climate, microclimate, and energy budget of a polar semidesert on King Christian Island, N. W. T., Canada. Arctic Alpine Res. 12, 161-170. Alphalo, P. J., and Jarvis, P. G. (1991). Do stomata respond to relative humidity Plant Cell Environ. 14, 127-132. Alphalo, P. J., and Jarvis, P. G. (1993). The boundary layer and the apparent responses of stomatal conductance to wind speed and to the mole fractions of CO, and water vapour in the air. Plant...

Patterns and Controls of Organic Matter Turnover between Ecosystem Types

The present magnitude of soil organic matter accumulation is a function of the balance between organic matter production and decomposition. The decomposition rate generally increases with increased temperature but decreases with soil water saturation at a level where permanent or periodic anoxic conditions are created. On the other hand, net primary production appears to be less affected by anoxia because most plant species in the wettest ecosystems are adapted to anoxic conditions. For...

Climate and Soil Water

Precipitation or water supply is fundamental to terrestrial ecosystem evaporation. In the boreal zone, it is relatively sparse. Precipitation cannot generally be exceeded by evaporation in the long term. Ground water collection areas are exceptional in that water supply for evaporation is greater than the precipitation. An example is the type of wetland known as a fen. However, precipitation is the primary source of water in the boreal zone and besides the orographic effect mentioned earlier,...

Appendix

The advantages of being evergreen. Trends Ecol. Evolut. 10, 402-407. Bakwin, P. S Tans, P. P., White, J. W. C and Andres, R. J. (1998). Determination of the isotopic (l3C l2C) discrimination by terrestrial biology from a global netweork of observations. Global Biogeochem. Cycles 12, 555-562. Bartlein, P. (1998). Personal communication. Buchmann, N. and Ehleringer, J. R. (1998). A comparison of CO concentration profiles, carbon isotopes, and oxygen isotopes in C4 and C, crop...

Kinds of Diversity

When considering the diversity of the biological systems of the earth, we traditionally consider only species. In recent times though, there has been an additional, and important, emphasis on the other dimensions of biological diversity including genetic, population, community, ecosystem, and landscapes diversity. This has been an important change in emphasis since it points to, as one example, the very important role that landscape configuration plays in the transfer of materials in the earth...

Summary

Early evolution produced organisms with generalized compounds and metabolic pathways that have had a profound effect on how the earth system operates. With the development of the an-giosperms and the coincident adaptive radiation of animals, novel and diverse chemical compounds have evolved. Many of these compounds have also had impacts on biogeochemistry, in some cases only locally, but in others more generally. We are now witnessing a major biological revolution with the mixing of biota...

Optimizing C02 Emissions

We turn now to the problem of coupling the impulse-response model summarized above to a simple socioeconomic model. The coupled model will then be applied to determine the optimal C02 regulation policy that would minimize the net impact of climate change. This can be represented generally as the sum of two contributions the direct and indirect costs of climate change itself (termed climate damage costs in the following), and the costs incurred in reducing C02 emissions (abatement costs). We...

Introduction

The protection of the world climate or components thereof has become the object of international agreements since the end of the seventies. The most important agreements to that extent are the Convention on Long-Range Transboundary Air Pollution, 1979' and its Protocols2, as well as the Vienna Convention for the Protection of the Ozone Layer, 19855 and its Protocol (Montreal Protocol on Substances that Deplete the Ozone Layer, 1987).4 However, only the United Nations Framework Convention on...

Observational Evidence

While the variations of climate over time scales of ten thousand to a hundred thousand years in all likelihood are caused by variations in solar irradiation over the year due to orbital effects, the so-called Milankovitch effect (Milankovitch, 1920, 1941 Berger, 1988), climate variations on shorter time scales are still rather mysterious. The most spectacular of these variations, at least as interpreted from ice-core measurements, appear to have amplitudes of several degrees Kelvin and were...

Commitments of States Parties under the Climate Change Regime

It is the ultimate objective of the Framework Convention to stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the sIn addition to carbon dioxide, the concerned gases include nitrous oxide, methane, sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons. Other gases, such as chlorofluorocarbons (CFCs), also exhibit greenhouse effects but are controlled by the Montreal Protocol. As to the scientific and ethical...

Acknowledgments

The author acknowledges the invaluable intellectual input of C. Trudinger, R. Langenfelds, R. Francey, and I. Enting. The author also acknowledges the use of data from CSIRO-GASLAB and the NOAA Climate Diagnostics Monitoring Laboratory. This study was carried out with support from the Australian Government through its Cooperative Research Centres Programme. Balkanski, Y Monfray, P., Battle, M and Heimann, M. (1999). Ocean primary production derived from satellite data An evaluation with...

C02Phosphorus Interactions in Tropical Forests

In this section we use a simple model to examine the possible magnitude of phosphorus constraints on the CO, fertilization response of tropical rain forests. The model presented is based on that originally developed by Lloyd and Farquhar (1996) and modified by Lloyd (1999a). In brief, the model consists of a simulation of ecosystem plant growth in response to changing C02 concen trations coupled with the Rothamstead model of soil carbon dynamics (Jenkinson and Rayner, 1977). In Lloyd (1999a),...

Present Status of Global CModels

Recently, Rayner et al (1999) developed a 3D time-dependent inversion model to determine interannual variability in the regional terrestrial and oceanic uptake of fossil-fuel C02 over the last two decades. The Rayner et al. study is used here as a benchmark against which the potential for improved precision and spatial resolution of flux estimates from atmospheric composition measurements is explored. In the Rayner study, extended records of monthly average concentrations of C02 in background...

Woody Plant Encroachment and Ecosystem Biogeochemistry

Changes in soils and microclimate accompanying long-term heavy grazing may have shifted the balance in favor of N2-fixing or evergreen woody plants which are better adapted than grasses to nutrient-poor soils and warmer, drier microenvironments. The establishment of trees and shrubs would have been further augmented by grazing-induced reductions in herbaceous competition and fire (Archer, 1995a). In addition, the woody plants at La Copita are highly unpalatable, and browsing by wildlife or...

Signature of Ecosystem Respiration

Recently, an increasing number of studies have evaluated the 13CO, exchange of terrestrial ecosystems, applying the experimental methods outlined above. Results for 51 different forest and TABLE 2 Plant-Specific Physiological Parameters* Tropical evergreen Tropical raingreeir' Temperate broadleaved evergreen Temperate sumrnergreeir' Subtropical temperate conifer Boreal evergreen Boreal deciduous1' Nontrees Temperate grass'1''' Tropical grass Desert woody shrub''1 Tundra woody shrulr Cold...

Concluding Remarks

Current chemical transport models of the atmosphere, which typically include 50-100 chemical compounds and 150-250 chemical reactions, reproduce with reasonable success the global behavior of the chemical system in the atmosphere. Differences between the results provided by these models remain substantial and will have to be addressed in the future. These models are used to explain the dramatic changes that have occurred in the chemical composition of the atmosphere over the last century and to...

Physiological Basis for C3C4 Plant Distributions

Photorespiration impacts both maximum photosynthetic rate and photosynthetic light-use efficiency (Bjorkman, 1966 Ehleringer and Bjorkman, 1977 Ehleringer and Pearcy, 1983 Sage and Monson, 1999). One consequence is that light-use efficiency or quantum yield for C02 uptake differ between C3 and C4 taxa (Ehleringer and Bjorkman, 1977). The quantum yield is defined as the slope of the photosynthetic light-response curve at low light levels. As the total leaf area within a canopy increases, an...

Biogeochemistry The Jena Perspective

In the late 20th century, biogeochemistry emerged as a new discipline in which the biological, physical, and human sciences collaborate (CGCR, 1999 Schlesinger, 1997). Biological, because the chemical cycles of the planet are mediated by life (Table 1). Physical, because of the strong coupling between climate and atmospheric composition so evident in the glacial-interglacial record of the ice cores (Fig. 1). And, human, because of the massive human disruption of the planet's carbon and nitrogen...

Forest Evaporation Tree Life Form and Nitrogen

Among boreal zone vegetation, forest E is unique in its variable relation with E (Table 3). According to three of these studies that are comparable, the differences in Eeq are associated with the three tree life-forms found in the boreal zone, namely, deciduous broad-leaved, deciduous needle-leaved, and evergreen needle-leaved (Table 6). During summer, the former two life-forms mostly bear fully grown leaves (see Black et al., 1996). However, life-form is not the only cause of difference in E...

Variability in Processes

The Kyoto protocol allows the compensation of fossil fuel emission by biological sinks without defining its components. In contrast to plant physiologists who are mainly concerned with photosynthesis, land managers are mainly interested in growth of products (timber, grain), but the atmosphere integrates carbon assimilation and respiration which includes the soil. In addition, carbon is released from ecosystems not only by respira- -22 -24 -26 -28 -30 -32 -34 -36 -38 -40 -22 -24 -26 -28 -30 -32...

Integrative Research Approach

The brief presentation of the information content of atmospheric molecular oxygen and the oxygen isotopes focused primarily on the individual merits of each tracer. However, as evident from the discussion of the combined CO, and 02 budgets, there exists considerable additional synergy if the tracer information is used in a combined, integrative way. Up to now, studies that combine the information from several of these tracers have not been attempted, in part because abundant atmospheric...

Info

Should Phosphorus Availability Be Constraining Moist Tropical Forest Responses to Increasing C02 Concentrations J. Max Planck Institute lor 1. Biogeochemistry t-.ii . -i r i t rr, lei 1a Germany Phosphorus in the Soils ot the Moist M I Bird States and Fluxes of Phosphorus in Moist Tropical Forests 98 Australian National University 4. Linking the Phosphorus and Carbon 103 Foundation Wageningen, The Netherlands Moist tropical forests account for a substantial amount of global plant productivity....

Foreword

Hspecially during the past century, land use changes and agricultural and industrial activities have been growing so rapidly that their effects on the environment, including the chemical composition of the global atmosphere have bccomc dearly noticcable on all scales. The first realization of the possibility of global effects was conncctcd with the growth of the greenhouse gas carbon dioxide measured by C. 1). Keeling and R. Revelle, on the basis of these measurements they stated that humanity...

Global C02Measurements

The rest of this contribution concentrates on recent and potential progress in the measurement of atmospheric C02 mixing ratios and related species. The challenge for such measurement programs is to monitor, with high precision, the temporal changes and or spatial gradients of CO, and related species. Conventional methodologies for monitoring atmospheric C02, developed over the past 40 years, show a number of shortcomings when examined in the light of the requirements for improved estimates of...

The Kyoto Protocol as a Learning Treaty

The Kyoto Protocol illustrates the setup of a learning treaty management system. The Protocol spells out the states parties' obligations by stipulating differentiated targets and time tables. It takes a number of institutional steps designed to ensure the implementation of the Protocol as a whole and of the commitments of each single state party.44 The Conference of the Parties shall keep the implementation of the Protocol under regular review and it may take decisions to promote its effective...

Interannual Variability

It is possible to perform a similar analysis of the interannual variability of ocean flux (and its relationship to atmospheric concentration measurements) as for the long-term mean. Once again, one cannot consider the ocean alone when interpreting atmospheric signals, so I will consider the combined effect of various scenarios of land and ocean fluxes in the atmosphere. As with the long-term means, even the broadest question regarding interannual variability in atmospheric CO, growth-rate is...

Types

Carbon sequestration has an additional component, namely, the biology of the species involved. There has been an ongoing discussion about the role of biodiversity in the carbon sequestration process and this is not captured by a classification of species into functional types. In a pan-European field experiment it was shown (Hector et al., 1999) that the aboveground biomass of grasslands during a growing season increased linearly with species richness and richness of functional types (Fig....

Dilemma

Introduction Apples and Bencdick1 2. Montreal An Unlikely Success 3. Lessons from the Ozone 4. Climate Change The Road to 5. The Framework Convention on Climate 6. Tortuous Targets in 7. When Will the Kyoto Protocol Come into 8. Unlearned 9. Time to Move On A Longer Term 10. A Teclmology-Based Strategy for the Future Eight Points for Action 328 References The emotion is to be found in the clouds, not in the green solids of the sloping hills or even in the gray...

The Global C02Measuring Network

It is clear that such unanticipated discrepancies between results from different measuring laboratories are a major obstacle for high-precision merging of data sets. The merging is highly desirable from the point of view of maintaining adequate spatial monitoring of global trends and for identification of regional source sink changes from atmospheric inversion techniques. From this perspective, we conclude this chapter by outlining an international calibration strategy that aims to overcome...

Summary and Conclusions

To summarize the results presented here, long-term trends in concentrations of various atmospheric species provide a reasonable and consistent constraint on the net fluxes of carbon into the ocean and terrestrial biosphere at global scales. At regional scales the picture becomes more confused and the constraint weaker. Agreement over the southern hemisphere oceans appears to be the strongest, at least when considered as a whole. There is less agreement for the rest of the globe, with...

And Managing Risks1

Center of Technology Assessment in Baden-Wuerllendjerg Stuttgiirt, Germany Institute of Soil Science and Forest Nutrition, University of Gottingen, Go lingen, Germany 303 2. Risk Evaluation and Risk 4. Application to Environmental Risks from Subtances2 310 5. Some Conclusions for a Deliberative References

Comparison of Observed and Modeled Ae Estimates

Good agreement between measured and modeled Ae values is found for the boreal zone, the humid tropics as well as for ecosystems in the Southern Hemisphere (Fig. 4). However, measured values for Ae are higher than modeled estimates in the temperate latitudes. In the mid-latitudes, there are several reasons modeled results might differ from observations by up to 5 o. We will discuss several potential explanations in the paragraphs below. The main issue is probably a result of measurement sampling...

Herbaceous Retrogression and Soil Carbon Losses

Simulations with the CENTURY biogeochemistry model (Parton et al, 1987, 1988, 1993) parameterized for assumed presettlement conditions (light grazing, fire at 10-year intervals), soil texture, and climate of the La Copita projected that soil organic carbon (SOC) would have been on the order of 2500 g m-2 to a depth of 0-20 cm (Hibbard, 1995). The SOC values from this assessment were then used as a baseline against which historic effects of heavy, continuous livestock grazing were evaluated. In...

Results from Climate Change Prediction Experiments

Aerosols Transport Cycle

As we have seen in the previous section, there is still a considerable spread between different climate models in the equilibrium response to a given forcing. Similar differences can be found in transient experiments. The main reason is that the degree of climate change strongly depends on the dynamical response of the coupled system. The marked surface warming of the Northern Hemisphere during the past 20 years, for example, is strongly influenced by a positive phase of both ENSO (stronger El...

Nitrogen Supply and Forest Productivity in a Landscape Perspective Hypotheses

There may be several explanations for the increase in forest productivity (and the correlation between base cations and N) down slope major slopes in Fennoscandian forest landscapes (Tamm, 1991 Giesler et al., 1998 Table 1). One category of these explanations (Fig. 3) refers to transport of N toward toe slope areas. As N is lost by leaching from large recharge areas, there should be a concentrated flux of N in the smaller groundwater discharge areas. Rohde (1987) reported that groundwater...

Mechanisms for Enhanced Phosphorus Uptake in Low P Soils

Even in very fertile soils, phosphorus concentrations in the soil solution are low, rarely exceeding 10 M. This is several orders of magnitude lower than the concentration of phosphorus in plant tissues, typically 5-20 mM (Marschner, 1995 Raghothama, 1999). It is therefore not surprising that plants have developed several specialized physiological and biochemical mechanisms for acquiring and utilizing phosphorus. Our purpose here is to consider these mechanisms, especially as they relate to...

Simulated

FIGURE 11 Observed surface temperature trend for 1900-1994 and simulated trend for the same period with the ECHAM4 OPYC3 coupled climate model. FIGURE 11 Observed surface temperature trend for 1900-1994 and simulated trend for the same period with the ECHAM4 OPYC3 coupled climate model. simulation, a reasonably good agreement is found (Fig. 11). We will next investigate the geographical relation between the forcing and the response to forcing in the three transient experiments. This is done by...

Challenge

E. Allison CSIRO At mospheric Research, Aspendale. Victoria and Cooperath v Research, Centre tor Southern Hemisphere Meteorology, Clayton, Victoria. Australia 2. Present Status of Global C-Models 3. Global 4. The global C02-Measuring The long lifetime and rapid mixing of C02 in the atmosphere provide a large-scale integration of surface fluxes, while, with sufficient measurement precision, signatures of individual surface source or sink regions can still be...

Tropical Plant Responses to Increases in Atmospheric C02 Concentrations

From Sec. 4.1 it can be concluded that plants typically found on nutrient-poor tropical soils may be relatively slow-growing, at least by the standards of the moist tropics. And also given that many species associated with these forests do not appear to be able to respond significantly to phosphorus fertilization (Sec. 4.1) it might also be argued that these species may not be able to significantly increase their growth in response to increases in ambient CO, (Poorter, 1993, 1998). On the other...

New Approaches to Functional Diversity

While traditional functional groups and species concepts have identified problems, other approaches show promise, at least for identifying sensitivities. Global applications of the Century ecosystem model (Parton et al. 1994 Schimel et al., 1996) were carried out. The model was set up with a relatively large number Decreasing species richness (log, scale) Decreasing species richness (log, scale) Decreasing functional group richness Decreasing species richness (log2 scale) FIGURE 8 A...

Distribution of Organic Matter

Compared to other ecosystem types, arctic and alpine vegetation have low plant biomass and stocks of carbon, mainly because of the lack of a tree stratum and the often spotty vegetation. For GLOBAL BIOGEOCHEMICAL CYCLES i.V THE CLIMATE SYSTEM Copyright 200 bv 1 . . Press. A rights of reproduction in ei1 torm reserved. TABLE 1 Comparisons of Carbon Pools in Arctic-Alpine Tundra, in the Neighboring Boreal Zone, and the World's Total. Area (106 km) Soil(gm 2) Vegetation (g m-2) Soil Vegetation...

Recognizing the Presence of C3 and C4 Ecosystems in the Paleorecord

Carbon isotope ratios can be used to identify the presence of C3 versus C4 photosynthesis in the fossil records. Large differences in discrimination against 13C02 by the initial carboxylation reactions in C3 (RuBP carboxylase) and C4 (PEP carboxylase) photosynthesis result in significant differences in the carbon isotope ratios (8I3C) of C, and C4 plants (Farquhar et al., 1989). Modern C, plants average approximately 27 o and C4 plants average approximately 13 o (Fig. 3). The observed ranges of...

The Images Model

One of the exciting challenges for the scientific community in the coming decade will be the development of coupled earth system models that account for the interactions between the biogeochem-ical cycles and the physical climate system. At present, most simulations of the atmospheric composition are performed using chemical transport models in which the atmospheric dynamics are prescribed (based on meteorological analyses) or calculated by an atmospheric general circulation model. Like most...

Degradation Ecological Versus Socioeconomic

Degradation associated with desertification or xerification in arid environments (West, 1986 Rapport and Whitford, 1999) or deforestation in humid environments is in sharp contrast to that associated with thicketization of grasslands and savannas in mesic environments (Fig. 2). Desertification and deforestation typically have negative consequences both ecologically and socioeco-nomically. Thicketization has some adverse socioeconomic implications, as it reduces the capacity of rangelands for...

Responses to Water Applications

Water has been applied to several arctic ecosystem types to simulate increased precipitation, with the expectation that the additions would enhance plant production. The production could be stimulated either directly as a response to decreased drought, most likely to occur in dry polar deserts or semideserts (Aleksandrova, 1988 Bliss et it ., 1984), or indirectly by enhancement of nutrient supply to plants. For instance, increase in soil moisture facilitates the transport of nutrients toward...

Atmospheric Molecular Oxygen 21 Overview

Oxygen is one of the most abundant elements on earth. It is contained in most rocks and it is a fundamental constituent of the water molecule. Oxygen exists in the atmosphere in the form of molecular 02 with a content of 20.95 , it is the second most abundant atmospheric gas after molecular nitrogen. Atmospheric molecular oxygen is produced during photosynthesis by terrestrial vegetation and marine phytoplankton, and it is consumed during autotrophic respiration by plants and respiration of...

Conclusions

In the boreal zone, summer rainfall frequency and quantity decline significantly from south to north, except in maritime Scandinavia. Correspondingly, the vegetation changes from forest to tundra with wetland being relatively ubiquitous. Average rainfall rate and soil water storage capacity range from ca. 0.5-2.0 mm day-1 and 8-13 mm water per 0.1 m soil, respectively. Snowmelt generally ensures a relatively full store of soil water at the beginning of summer. Wetland can receive a supplemental...

Do Species Losses Matter for Biogeochemical Cycling

As in any comparison, one can find similarities among sets or find differences. First, I consider briefly the similarity arguments, that is, the position that species differences are not large enough to affect the kinds of processes that occur at the global level. From a functional point of view one can focus on similarities among species, as Eigen and Schuster (1977) have noted, millions of species, plants and animals, exist, while there is only one basic machinery of the cell one universal...

The Max PlanckInstitut fur Biogeochemie

The Max-Planck-Gesellschaft (Society) has a number of institutes conducting biogeochemical research. The Institutes for Chemistry and Meteorology have long had programs addressing atmosphere-biosphere exchange and the carbon cycle. The MaxPlanck-Institut for Biogeochemistry was set up to provide an intellectual focus for research on the global biogeochemical cycles. Biogeochemistry had emerged in the 1990s as a center of both intellectual and policy ferment and yet the discipline lacked a...

And Climate

Department of Biology 2. A Physiological Basis for C3 C4 Plant Salt Lake City Utah A Brief I Iistory of Atmospheric Carbon Dioxide Levels 268 Thurc E Ccrling 4. Recognizing the Presence of C, and C4 Ecosystems in the Paleorecord 269 Department of Geology and 5. Global Expansion of C4 Geophysics University 6 q q Dynamics during Glacial-Interglacial Salt Lake City Utah Photosynthetic Pathway Distribution in the Modern World 273 8. Photosynthetic Pathway Impacts References

Cellulose

Although cellulose appeared 3.5 billion years ago it was not until the evolution of land plants that it became universally present in plants. Besides providing rigidity, so that cellular turgor could develop, it also provided mechanical strength due to its layered microfibril development. The tensile strength of cellulose microfibrils is over twice that of steel. The strength of cellulose is diminished, however, when it is wet. Materials embedded in the matrix of cellulose, such as lignin,...

Some Conclusions for a Deliberative Process

Central to our concept of risk evaluation and management is the attempt to initiate a deliberative process, because rational criteria of evaluation ought to be applied in discursive settings and communicated to the political decision makers and the public at large. So the deliberation for an adequate risk-policy should take place within a multistage communication process that is characterized by forms of mutual consultation and a public network of communication. To assure a rational...

Nutrient Distribution and Controls of Nutrient Cycling

The ecosystem pools of mineral nutrients are divided between the above- and belowground biota, the dead organic matter, and an inorganic pool, which probably constitutes the major source of plant-available nutrients. The difference in distribution of nutrients between soil and vegetation is still more pronounced than that in the distribution of C because the soil organic matter generally is enriched in nutrients compared with the vegetation (Jonas-son and Miclielsen, 1996). For instance, tlie...

Biogeographical and Historical Contexts

The La Copita Research Area (27 40'N 98 12'W elevation 75-90 m ASL) is situated in the northeastern portion of the North American Tamaulipan Biotic Province (Blair, 1950) in the Rio Grande Plains of southern Texas. The potential natural vegetation of this region has been classified as Prosopis- Acacia -Andropogon-Setaria savanna (Kiichler, 1964). However, the contemporary vegetation is subtropical thorn woodland (McLendon, 1991) and occupies about 12 million ha in Texas alone (Jones, 1975). The...

What Do We Have and What Are We Losing

At present there are 1.7 million described species, nearly a million of which are insects. There are many more. UNEP (1995) gives the best guess that there are six undescribed organisms for every one that has been described. These are very large numbers. The number of these species whose existence is threatened by the activities of humans is considerable. For the better-known groups, such as mammals, birds, fish, and higher plants, we have good estimates of the numbers of threatened species....

Analysis of the Role of Diversity and Biogeochemistry

To this point we have looked to the past to understand the changing relations between biodiversity and biogeochemisry. Recently, there has been considerable research into the role of species richness in ecosystem functioning, including biogeochemistry. There have been explicit experiments on this issue as well as observations on the impact of addition and deletion of species on natural ecosystems. The experimental studies, although the most direct attack on this issue, have been somewhat...

And Biogeochemistry

What Do We I lave and What Are We Stanford University, 2. Do Species Losses Matter for Biogeochemical Stanford, California , T,. , ,-t . 3. Kinds of 4. Evolution of Functional 6. Evolution of Polyphenols 7. Build-Up of Carbon and the Evolution of 8. Analysis of the Role of Diversity and References The phenomenon that I probe here is the relationship between biodiversity and biogeochemistry. To do this I take an evolutionary as well as an ecological approach. The basic question...

Photosynthetic Pathway Distribution in the Modern World

The current distributions of C4 plants within grassland ecosystems at an atmospheric C02 level of 350 ppmV are well predicted by the quantum-yield model (Fig. 1). Across the Great Plains of North America, the crossover between C3- and C4-dominated grasslands is predicted to occur at a latitude of approximately 45 N (Figure 7). Both long-term aboveground harvest studies (Epstein et al, 1997) and belowground soil organic carbon studies (Tieszen et al, 1997) independently indicate a C3 C4...

Global Environment and Society Models

The general structure of an elementary global environment and society (GES) model designed for integrated assessment studies is illustrated in Fig. 1. The various interactions between the global environment, the socioeconomic system, and the policy makers are shown. These include both the direct physical coupling and the communication pathways that transform scientific knowledge and stakeholder positions via the media into public opinion and political action. A more disaggregated representation...

Long Term Mean Ocean Uptake

Here I review three largely independent lines of evidence concerning the net uptake of carbon by the global ocean. At the outset I should address some ambiguity about the word uptake. The word should literally refer to the net storage of carbon in the ocean. However, many of the studies cited here calculate the net flux of carbon across the air-sea interface or deduce the ocean uptake from the terrestrial uptake. Carbon entering the ocean by other routes may not be counted. This becomes...

Are there Unaccounted Plant Sources of Limiting Nutrients

The assumption hitherto has been that plants only, or almost exclusively, take up N in inorganic form as NH44 or NO, - This assumption has been questioned recently, and there are strong FIGURE 2 Biomass and nitrogen accumulation (means SE) in Erio-phontin vaginatiun grown in NO,, NH4, and amino acids (AA) during 24 days. Treatment responses with the same superscript letter above the bars are not significantly different at p 0.05. (Redrawn from Chapin et ill., 1993, with kind permission from...

Interactions between Hydrochemistry N Dynamics and Plants at Betsele A Model System

At Betsele, 64 N in northern Sweden, there is a remarkable N-sup-ply gradient from a groundwater rcchargc area to a discharge area (Giesler et al., 1998). The gradient encompasses a wide range of the variation in soil pH, N in soils, ctc., and in plant community composition found in Fennoscandian boreal forests (Figs. 2 and 4). Similar but less pronounced gradients arc found along any major slope, but this site was chosen to enable studies of large variability on the same type of...

Net CarbonGain

Gross-Primary-Productivity-GPP ( photosynthesis) Net-Primary-Productivity-NPP 50 ( plant growth) Net-Ecosystem-Exchange-NEE Net-Ecosystem-Productivity-NEP ( change in litter & organic layer) ( change in charcoal & r siliant humus) respiration of microbes, disturbance by trends (C02 & climate change) episodic disturbancees (harvest & fire) accumulates organic material in the organic layer. This material is being decomposed to a level, that the local decomposers cannot digest this...

Response to Forcing of the Climate System

Climate 60n And 60s

Over a time span of a few years the heat balance of the earth can generally be considered to be in balance, which means that the incoming solar radiation, S, is balanced by the outgoing long wave radiation, F. What happens then when suddenly there is a change in either S or F Let us assume, for example, that there is a sudden increase in C02 concentration to twice the present value. The immediate response is a reduction in the outgoing longwave radiation at the tropopause of about 3.1 W nT2 and...

Biogeochemical Cycles in the Climate System

Ernst-Detlef Schulze, Martin Heimann, Sandy Harrison, Elisabeth Holland, Jonathan Lloyd, Iain Colin Prentice, and David Schimel Max-Planck-Institute for Biageochemistry Jena, Germany San Diego San Francisco New York Boston London Sydney Tokyo A Harcourt Science and Technology Comj This book is printed on acid-free paper. & Copyright 2001 by ACADEMIC PRESS All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical,...

Research Challenges

The discipline of biogeochemistry confronts a wide array of scientific and methodological challenges, as is evident in the balance of this book. These are not limited to the cycles of carbon and nitrogen, but include the role of phosphorus, iron, calcium, aluminum, and acidity, to name just a few. In this section, I will identify four cross-cutting challenges that illustrate aspects of the science. 1.1 Large-Scale Carbon Sinks Detection and Attribution The problem of the terrestrial missing...

Applicability of Experimental Manipulations

Experimental manipulations of the environment have been a common way of exploring how tundra ecosystems and their components react to environmental changes. Such experiments have, indeed, given valuable information on environmental controls at various levels of resolution, although of necessity the information is limited by observation series over relatively short time spans. Hence, the time constraints of experimentation set a limit to the observations of long-term responses, which must be...

Experimental Evidence

Since the 1940s, experiments with additions of nutrients on hundreds of plots in the field have shown a more or less strong N limitation on forest growth in Fennoscandian forests (Tamm, 1991 Binkley and Hogberg, 1997). In such trials, additions of NII4NO, increase forest production, but they frequently acidify the mineral soil (Fig. 5 Tamm, 1991 Binldey and Hogberg, 1997). This means that the BC A1 (or Ca Al) ratio is lowered, while forest production increases, and definitely implies that the N...

Trees in Grasslands Biogeochemical Consequences of Woody Plant Expansion

Biogeochemical Cycling Trees

Woody Plant Encroachment in Grasslands and The La Copita Case Degradation Ecological versus Implications for Ecosystem and Natural Resources Management Summary Steve Archer, Thomas W. Boutton, and K. A. Hibbard Key Words carbon, disturbance, grazing, fire, global change, hydrocarbons, land cover, modeling, nitrogen, NOx, savanna, sequestration, soil respiration, succession, tree-grass interactions, vegetation dynamics, woody plant encroachment The term savanna typically denotes plant...

Biogeophysical Feedbacks and the Dynamics of Climate

Potsdam-lastimte for 2. Klimafolgenforschung ' , . . Potsdam, Germany 3- Multiple 4. Transient 5. Perspectives Traditionally, vegetation has been considered a more or less passive component of climate. For example, Alexander von Humboldt (1849) imagined the desertification of North Africa to be caused by an oceanic impact. He argues that somewhere in the dark past, the subtropical Atlantic gyre was much stronger and flooded the Sahara, thereby washing away vegetation and fertile...

Stable Isotopes of Oxygen 31 Overview

The three stable oxygen isotopes, 'O, ''O, and lsO in both, C02 and 02, constitute important tracers of the global carbon and oxygen cycles. Besides revealing crucial information in local process studies (see Lloyd, this volume), they may also be observed and modeled on the global scale. Unlike carbon or oxygen, however, these isotopes are not conserved in the carbon or oxygen cycle, but are constantly exchanged at a few critical connection points with the hydrological cycle (which contains...

Montreal An Unlikely Success Story

As a historian once observed, all revolutions seem impossible before they occur and inevitable afterwards. Now that chlorofluo-rocarbons (CFCs) have become a household word, we forget the global firestorm of controversy that was provoked by a technical article written in 1974 by two scientists at the Universe of California at Irvine. Sherwood Rowland and Mario Molina hypothesized that certain anthropogenic chemicals could damage ozone molecules 30-50 kilometers above the earth's surface (Molina...

Implementation Measures

The Kyoto Protocol provides some guidance as to how the obligations under Article 3 are to be implemented by states parties. Article 2 of the Protocol provides a list of potential policies and measures that aim, generally speaking, at the enhancement of energy efficiency and promotion of sustainable agricultural practices. This list, however, is only illustrative. At the national level, each state party may select its own policies and measures provided that it produces the required results. The...

Paleobiogeochemistry

Methane Carbon Mineral Dust Aerosol Scientific Challenges Posed by the Ice-Core Records G ophysique de Environnement St. Martin d H res. France Toward an Integrated Research Strategy for Paleobiogeochemistry Paleobiogeochemistry this word, as far as we know, did not previously exist. It defines a newly emerging research field that, we believe, will within the next decade come to play a central role in our understanding of the earth system and of how human activities are modifying that system....

Evolution of Polyphenolic Compounds

Lignin plays an enormously important role in determining the utility of cellulose as described above, by adding strength to it as well as by protecting it from pathogens. Lignin, however, also plays a number of different roles in plants and has done so through time. It is thought that the aromatic amino acids, which are the precursors to lignin, as well as tannins and flavonoids, evolved in aquatic algae as protectants against high UV-B radiation (Rozema et al, 1997 Lowry et al., 1980)....

When Will the Kyoto Protocol Come into Force

In an attempt to maximize the efficiency of investments and thereby lower the economic costs of emissions reductions, the Kyoto Protocol established three flexibility mechanisms (1) joint implementation, whereby an Annex I country could invest in emissions-reducing projects in another Annex I country and receive some credit against its own target, provided that such project entails a reduction in emissions by sources, or an enhancement of removals by sinks, that is additional to any that would...

Historical Perspective

That N can limit production in temperate forests was first revealed through experiments conducted by Mitchell and Chandler in the U.S. (1939) and Hesselman and Romell (Fig. 1) in Sweden (reviewed by Tamm, 1991). Meanwhile, many forest soil scientists tended to focus on the role of other elements, notably the so-called base cations, possibly because benefits of liming had been recognized in agriculture. The first generation of liming trials in forests were, thus, initiated to see if the...

Woody Plant Encroachment in Grasslands and Savannas

Woody plant encroachment has been widespread in grassland and savanna ecosystems of North and South America, Australia, Africa, and southeast Asia over the past century (Table 1). This encroachment, typically by unpalatable trees and shrubs, has gone to completion on some landscapes and is in progress on others. It jeopardizes grassland biodiversity and threatens the sustainability of pastoral, subsistence, and commercial livestock grazing (Rappole et al, 1986 Noble, 1997). As such, it may...

Risk Evaluation and Risk Classification

2.1 Main Characteristics of Risk Evaluation The two central categories of risk evaluation are the extent of damage and the probability of occurrence (for definitions see Knight, 1921 National Research Council, 1983 Fischhoff ct al 1984 Fritzsche, 1986 Short, 1984 Bechmann, 1990 IEC, 1993 Kolluru and Brooks, 1995 Banse, 1996 Rosa, 1997). Damage should generally be understood as negatively evaluated consequences of human activities (e.g., accidents by driving, cancer by smoking, fractured legs by...

Input Output Balances and Nitrogen Limitation in Terrestrial Ecosystems

California 2. Long- Term Nutrient 3. A Simple 4. Pathways of N Loss 5. Constraints on N Fixation 6. Conclusions Why does the availability of N often limit net primary production (NPP) and other processes in terrestrial ecosystems For N to limit NPP in the long term, two conditions must be met N must be lost from terrestrial ecosystems by pathways that cannot be prevented fully by N-demanding organisms, and the power of N2 fixation to add new N to N-limited...

Changes in the Chemical Composition of the Global Troposphere

Ozone Column Abundance

The IMAGES model has been used to assess the impact of human activities on the chemical composition of the global troposphere. To quantify past, current, and future changes in tropospheric composition, IMAGES was used to simulate the preindustrial atmosphere (year 1850), a contemporary atmosphere (year 1990), and a future atmosphere (year 2050), respectively. As expected, the largest increase in ozone occurs in the lower troposphere in the Northern Hemisphere with changes of more than 70 at...

Technology Based Strategy for the Future Eight Points for Action

What kind of actions might these be The dangers of long-term global warming can only be averted if we (1) bring to market a new generation of technologies that will drastically reduce dependence on fossil fuels and or will capture and sequester carbon, and (2) gain the cooperation of key developing countries to limit their rapidly rising emissions. Fortunately, the two conditions are interrelated as we achieve the first, we will get the second. As the ozone history amply demonstrated, when...

Evaporation during Summer and Rainfall

The first boreal ecosystem we consider is that most analogous to water, namely, the wetland. During summer, P averaged 0.8 mm day-1 less than E for wetlands (Table 3). However, by definition, this comparison is incomplete for fens because water supply to this system exceeds rainfall by virtue of ground-water intrusion, although this is often difficult to quantify with certainty. In Table 3, the Saskatchewan, Zotino, and Schefferville sites were fens but it is not clear if ground water...

Physical Rationale

Stochastic forcing as originally suggested by Hasselmann (1976), is a mechanism that can generate low-frequency variations in the climate system. How does it work The atmosphere is constantly in motion and, while we do not think of atmospheric motion as being decadal in nature, atmospheric motion can readily induce decadal and longer motions in the more slowly varying systems (such as the ocean) that are coupled to the atmosphere. Sarachik et al. (1996) have suggested the analogy of the tossing...

Application to Environmental Risks from Substances2

4.1 Global Biogeochemical Cycles Are Influenced by Human Activity Carbon, nitrogen, and sulfur are essential to the life of animals, plants, and microbes. Interactions between these elements link the internal biogeochemistry of terrestrial ecosystems. Naturally, the availability of these substances is limited in terrestrial ecosystems and this has led to various adaptations of the biota. Nowadays, high anthropogenic emissions of various compounds of carbon, nitrogen, and sulfur have created a...

Nutrient Mineralization and Plant Nutrient Uptake

The net mineralization of nutrients is about an order of magnitude lower in arctic ecosystems than in the boreal region, largely because of constrained microbial activity (Nadelhoffer et al, 1992). There is also a pronounced seasonal variation in net mineralization. Several studies of both litter and soil organic matter mineralization have shown that winter mineralization is higher than summer mineralization (Giblin et al, 1991 Hobbie and Chapin, 1996 Shaver et al, 1998), which is surprising...

Implications for Ecosystem and Natural Resources Management

Marine Based Ice Sheet

Woody plant encroachment has been and continues to be a major problem in grasslands and savannas worldwide (e.g., Grossman and Gandar, 1989). Because of its direct effects on livestock production, FIGURE 11 Feedbacks between climate and atmospheric processes, ecosystem structure and function, and human activities. Dashed lines depict traditional research and public awareness solid lines denote areas requiring increased research emphasis. Understanding global change will ultimately hinge on...

Experimental and Analytical Methods

Flask samples of canopy air from a variety of ecosystems were generally taken from different heights within the canopy at different times during the day and the night. These measurements represent a wide range of canopy CO, concentrations ( C02 ). Dried canopy air was drawn through glass flasks, C02 were measured before the flasks were closed, and flasks were brought to the lab for further analyses (For more details on how to sample and how to prepare the air samples for mass spectrometric...

C3C4 Dynamics during Glacial Interglacial Periods

The quantum-yield model predicts that important changes in the global proportions of C4 biomass occurred during the Pleistocene glacial-interglacial transitions. Figure 1 shows that at very low atmospheric C02 levels, C4 plants can be favored even at moderately low temperatures. The oscillation between glacial and interglacial conditions reflected an oscillation between about 180 and 280 ppmV (Fig. 2, middle), respectively, based on the CO, concentrations in the Antarctic ice cores (Petit et...

Photosynthetic Pathway Impacts Herbivores

Megafaunal changes are correlated with a shift between C3- and C4-dominated ecosystems. Several lines of evidence suggest relationships between turnover of mammalian grazing taxa and the shifts between C3 C4 vegetation types. Cerling et al (1998a) reported abrupt changes in mammalian lineages in East Africa asso- 813C tooth ename equid ( ) other ( ) FIGURE 9 Faunal Change Index from the Pakistan, represented by the number of first (nf) and last n ) occurrences, including only occurrences (n0),...

Global Soil Organic Carbon Pool

Global Potential Soil Carbon

Introduction the Soil Carbon Pool and Global 2. Factors Affecting the Distribution of Soil Organic 3. Global Variations in the SOC 4. Limitations of Available Observational SOC 5. A Stratified Sampling 6. Conclusions Sandworld and 1. Introduction the Soil Carbon Pool and Global Change Estimates of the size of the global soil organic carbon (SOC) pool have ranged between 700 Pg (Bolin, 1970) and 2946 Pg (Bohn, 1976), with a value of around 1500 Gt now generally accepted as the most appropriate...

Global Expansion of C4 Ecosystems

Figure 5 shows that between 8 and 6 Ma there was a global expansion of C4 ecosystems (Cerling et al, 1997, 1998a). There is no conclusive evidence for the presence of C4 biomass in the diets of mammals before 8 Ma (Cerling et al, 1997 1998a), although the presence of small amounts of C4 biomass in diets is not excluded because of the uncertainty in the SI3C endmember for C, plants. By 6 Ma there is abundant evidence for significant C4 biomass in Asia (Cerling et al, 1993 1997 Morgan et al,...

Description of the Model

BIOME3.5 is an equilibrium terrestrial biosphere model based largely on the BIOME3 model of Haxeltine and Prentice (1996). BIOME3.5's main differences from its predecessor include the addition of a module to calculate isotopic discrimination during photosynthesis (Aleaf), the reparameterization of the original plant functional types (PFTs), and the addition of several new PFTs to reflect poorly represented vegetation types in the arctic and arid subtropics. Like BIOME3, BIOME3.5 is a coupled...

Introduction Apples and Oranges

In December 1997, after nights of bargaining that culminated two years of hard negotiations, representatives of 160 governments wearily agreed in Kyoto, Japan, on a protocol to supplement the 1992 United Nations Framework Convention on Climate Change. It was hoped that the Kyoto Protocol would represent a major step forward by the international community to mitigate emissions of greenhouse gases that could alter future climate. Before long, however, doubts emerged on whether the treaty was...

Past and Future Forest Response to Rapid Climate Change

University of Minnesota, St, Paui, Minnesota 2. Long-Distance 3. Estimating Jump 4. Interactions with Resident Vegetation Constraints on 5. Interactions with Resident Vegetation Competition for Light and Resulting Constraints on Population Growth 7. Conclusions References In response to large changes of climate during the Ilolocene, geographical ranges of tree species shifted northward in eastern North America, with range extensions occurring at rates of 10-100 km per century. Long-distance...

Monitoring Compliance and Enforcement

It has been frequently emphasized that the effectiveness of international environmental law depends on establishing international procedures or mechanisms that may be used to ensure compliance.3, International environmental law has developed several such mechanisms, one of them being the obligation of states parties to regularly report the national measures undertaken to pursuent to the respective international agreement. However, international environmental law does not entrust particular...

Impulse Response Climate Models

For any complex, nonlinear system such as climate, it is permissible, for sufficiently small perturbations, to describe the response of the system to external forcing in terms of a linearized response model. In the case of the climate system, the linearization condition is approximately satisfied for the external forcing due to anthropogenic greenhouse gas emissions if the temperature change remains below about 2-3 C. Measured in Kelvin relative to absolute zero temperature at 273 C, the global...

The IGBP Transect Approach

Although new satellite images allow a more and more detailed observation of the earth surface (e.g., Defries et al., 2000), the ground truth remains essential. This was recognized by IGBP as a significant problem because it remains impossible to study processes with global coverage. Continental transects were suggested that represent the major climatic regions of the globe and allow repeated observations at the same time (Walker et al., 1999). Continental transects were suggested for the boreal...