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)....

References

Mycorrhizas in tropical forests. In Mineral Nutrients in Tropical Forest and Savanna Ecosystems (J. Proctor, Ed.), pp. 169-188. Blackwell Scientific Publications, Oxford. Almeida, J. P. F., Ltischer, A., Frehner, M Oberson, A., and N sberger, J. (1999). Partitioning of P and the activity of root acid phosphatase in white clover (Trifolium repens L.) are modified by increased atmospheric CO, and P fertilisation. Plant and Soil 210, 159-166. Arnone, J. A., Ill and K rner...

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...

Conclusions

Single species appear to determine the NPP processes in the ecosystem in a more than proportional manner. It will be a major task of future research to identify these species and their characteristics and develop modeling approaches. 2. Current identification of biomes is not based on a functional analysis, and while some major biomes function similarly in carbon uptake (e.g., European conifer and deciduous forest), within-biome or-species effects can be extremely large. New ways of organizing...

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

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...

Summary and Conclusions

Observational data in combination with theoretical studies and modeling experiments suggest that the surface temperature of the Northern Hemisphere during the past 1000 years could be characterized as follows First, a slow ongoing cooling is by and large consistent with orbital forcing or the so-called Milankovitch effect. This amounts to an annual cooling of some 0.2 K over 900 years. Second, a rapid temperature increase starting at the beginning of the 20tli century remained more or less...

BuildUp of Carbon and the Evolution of Decomposers

By the Robinson (1990) hypothesis, effective lignin degradation did not appear until some 200 million years after lignin evolved with the appearance of basidiomycetes in the Pennsylvanian. This could explain the build-up of organic compounds during the late Mesozoic. With increasing oxygen content of the atmosphere, the increase in basiodimycetes and the evolution of angiosperms with lower lignin-content in the Late Cretaceous, carbon stores in the soils decreased. The events discussed so far...

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...

Plant Compounds and Their Turnover and Stabilization as Soil Organic Matter

Types Compounds Plant Residues

Czimczik, Christiane Kramer, Barbara L hkcr, and Michael W.I. Schmidt 2. Pathways of Soil Organic Matter 3. Stabilization of Soil Organic 4. Turnover of Soil Organic Matter The increase in atmospheric CO, because of fossil fuel emissions has been identified as a major driving force for global climate change. Soil organic matter (SOM) is expected to be an important sink for this carbon (Ciais et al., 1995 Schimel, 1995 Steffen et al., 1998). However, at higher mean...

Ecophysiological Information from Ae

It is well established that leaf carbon-isotope discrimination provides valuable information about the ratio of leaf assimilation to stomatal conductance (intrinsic water-use efficiency Farquhar et at, 1989). Based on field observations of Ac, Buchmann ct al. (1998) postulated that ecosystem discrimination might increase with decreasing ratio of ecosystem assimilation to canopy conductance (A Gc, in mol CO, per mol II,0). Using BIOME3.5, we tested this hypothesis for the 22 biomes simulated by...