Showing papers by "International Institute for Applied Systems Analysis published in 2003"

An inventory of gaseous and primary aerosol emissions in Asia in the year 2000

Abstract: [1] An inventory of air pollutant emissions in Asia in the year 2000 is developed to support atmospheric modeling and analysis of observations taken during the TRACE-P experiment funded by the National Aeronautics and Space Administration (NASA) and the ACE-Asia experiment funded by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA). Emissions are estimated for all major anthropogenic sources, including biomass burning, in 64 regions of Asia. We estimate total Asian emissions as follows: 34.3 Tg SO2, 26.8 Tg NOx, 9870 Tg CO2, 279 Tg CO, 107 Tg CH4, 52.2 Tg NMVOC, 2.54 Tg black carbon (BC), 10.4 Tg organic carbon (OC), and 27.5 Tg NH3. In addition, NMVOC are speciated into 19 subcategories according to functional groups and reactivity. Thus we are able to identify the major source regions and types for many of the significant gaseous and particle emissions that influence pollutant concentrations in the vicinity of the TRACE-P and ACE-Asia field measurements. Emissions in China dominate the signature of pollutant concentrations in this region, so special emphasis has been placed on the development of emission estimates for China. China's emissions are determined to be as follows: 20.4 Tg SO2, 11.4 Tg NOx, 3820 Tg CO2, 116 Tg CO, 38.4 Tg CH4, 17.4 Tg NMVOC, 1.05 Tg BC, 3.4 Tg OC, and 13.6 Tg NH3. Emissions are gridded at a variety of spatial resolutions from 1° × 1° to 30 s × 30 s, using the exact locations of large point sources and surrogate GIS distributions of urban and rural population, road networks, landcover, ship lanes, etc. The gridded emission estimates have been used as inputs to atmospheric simulation models and have proven to be generally robust in comparison with field observations, though there is reason to think that emissions of CO and possibly BC may be underestimated. Monthly emission estimates for China are developed for each species to aid TRACE-P and ACE-Asia data interpretation. During the observation period of March/April, emissions are roughly at their average values (one twelfth of annual). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of ±16% for SO2 to a high of ±450% for OC.

Speciation along environmental gradients

Abstract: Traditional discussions of speciation are based on geographical patterns of species ranges. In allopatric speciation, long-term geographical isolation generates reproductively isolated and spatially segregated descendant species. In the absence of geographical barriers, diversification is hindered by gene flow. Yet a growing body of phylogenetic and experimental data suggests that closely related species often occur in sympatry or have adjacent ranges in regions over which environmental changes are gradual and do not prevent gene flow. Theory has identified a variety of evolutionary processes that can result in speciation under sympatric conditions, with some recent advances concentrating on the phenomenon of evolutionary branching. Here we establish a link between geographical patterns and ecological processes of speciation by studying evolutionary branching in spatially structured populations. We show that along an environmental gradient, evolutionary branching can occur much more easily than in non-spatial models. This facilitation is most pronounced for gradients of intermediate slope. Moreover, spatial evolutionary branching readily generates patterns of spatial segregation and abutment between the emerging species. Our results highlight the importance of local processes of adaptive divergence for geographical patterns of speciation, and caution against pitfalls of inferring past speciation processes from present biogeographical patterns.

Age and individual productivity: A literature survey

Abstract: This article surveys supervisors' ratings, analyses of piece-rates and employer-employee datasets as well as other approaches used to estimate how individual productivity varies with age. The causes of productivity variations over the life cycle are addressed with an emphasis on how cognitive abilities affect labour market performance. Earnings tend to increase until relative late in the working life, while most evidence suggests that individuals' job performance tends to increase in the first few years of one's entry into the labour market, before it stabilises and often decreases towards the end of one's career. Productivity reductions at older ages are particularly strong when problem solving, learning and speed are important, while older individuals maintain a relatively high productivity level in work tasks where experience and verbal abilities matter more.

Punishment and reputation in spatial public goods games.

Abstract: The puzzle of the emergence of cooperation between unrelated individuals is shared across diverse fields of behavioural sciences and economics. In this article we combine the public goods game originating in economics with evolutionary approaches traditionally used in biology. Instead of pairwise encounters, we consider the more complex case of groups of three interacting individuals. We show that territoriality is capable of promoting cooperative behaviour, as in the case of the Prisoner's Dilemma. Moreover, by adding punishment opportunities, the readiness to cooperate is greatly enhanced and asocial strategies can be largely suppressed. Finally, as soon as players carry a reputation for being willing or unwilling to punish, highly cooperative and fair outcomes are achieved. This group-beneficial result is obtained, intriguingly, by making individuals more likely to exploit their co-players if they can get away with it. Thus, less-cooperative individuals make more-cooperative societies.

Population growth in space and time: spatial logistic equations

Abstract: How great an effect does self-generated spatial structure have on logistic population growth? Results are described from an individual-based model (IBM) with spatially localized dispersal and competition, and from a deterministic approximation to the IBM describing the dynamics of the first and second spatial moments. The dynamical system incorporates a novel closure that gives a close approximation to the IBM in the presence of strong spatial structure. Population growth given by the spatial logistic model can differ greatly from that of the nonspatial logistic equation. Numerical simulations show that populations may grow more slowly or more rapidly than would be expected from the nonspatial model, and may reach their maximum rate of increase at densities other than half of the carrying capacity. Populations can achieve asymptotic densities substantially greater than or less than the carrying capacity of the nonspatial logistic model, and can even tend towards extinction. These properties of the spatial logistic model are caused by local dispersal and competition that affect spatial structure, which in turn affects population growth. Accounting for these local spatial processes brings the theory of single-species population growth a step closer to the growth of real spatially structured populations.

Long-term development of acid deposition (1880–2030) in sensitive freshwater regions in Europe

Abstract: . Time series of the deposition of acidifying substances are a pre-requisite for the study of the acidification and recovery of ecosystems such as surface waters. This paper reports the derivation and calculation of deposition trends of the potentially acidifying compounds SO2, NOx and NH3 in sensitive freshwater regions in Europe studied in the EU-funded RECOVER: 2010 project. The time interval covered is 151 years: from 1880, which can be considered as the pre-industrial era in most countries, to 2030, taking into account the consequences of current emission reduction agreements in Europe. The historic and predicted emissions for European countries are used to calculate the deposition development in the study areas, using meteorologically averaged atmospheric source-receptor transfer coefficients derived from the EMEP Lagrangian acid deposition model. These time series were used as driving forces for the application of the dynamic acidification model MAGIC to study the acidification and recovery of sensitive freshwater ecosystems in Europe. Keywords: acid deposition, historic depositions, sensitive lake regions, Europe

Europe's population at a turning point

Abstract: Low birthrates in Europe have begun to generate negative population momentum, a new force for population shrinkage over the coming decades. Birthrates are low partly because of the current trend in Europe toward bearing children at later and later ages. A continuation of this trend could substantially exacerbate future aging of the population and contribute to a future decline in population size. Social policies and labor laws aimed at halting further increases in the mean age of childbearing are proposed in this Policy Forum.

Evolution of dispersal in metapopulations with local density dependence and demographic stochasticity.

Abstract: In this paper, we predict the outcome of dispersal evolution in metapopulations based on the following assumptions: (i) population dynamics within patches are density-regulated by realistic growth functions; (ii) demographic stochasticity resulting from finite population sizes within patches is accounted for; and (iii) the transition of individuals between patches is explicitly modelled by a disperser pool. We show, first, that evolutionarily stable dispersal rates do not necessarily increase with rates for the local extinction of populations due to external disturbances in habitable patches. Second, we describe how demographic stochasticity affects the evolution of dispersal rates: evolutionarily stable dispersal rates remain high even when disturbance-related rates of local extinction are low, and a variety of qualitatively different responses of adapted dispersal rates to varied levels of disturbance become possible. This paper shows, for the first time, that evolution of dispersal rates may give rise to monotonically increasing or decreasing responses, as well as to intermediate maxima or minima.

A synthesis of the impact of Russian forests on the global carbon budget for 1961–1998

Abstract: An attempt is made to synthesize the current understanding of the impact of Russian forests on the global carbon (C) budget for the period 1961–1998 (37 years), based on a detailed inventory of pools and fluxes in 1988–1992, and a historical reconstruction of a full forest carbon budget for 1961–1998. All major intermediate indicators of the budget (phytomass, net primary production, impact of disturbances, soil respiration, etc.) were independently estimated and compared with earlier reported results. During the entire period, the C pools of Russian forest land (FL, 882.0 × 10 6 ha in 1998) increased by 433 Tg C yr −1 , of which 153 Tg C yr −1 are accumulated in live biomass, 57 Tg C yr −1 in above- and below-ground dead wood, and 223 Tg C yr −1 are sequestered in soil. A significant part of this increase deals with land-cover changes. The annual average C uptake by the FL from the atmosphere, defined by a flux-based method, is estimated to be −322 Tg C yr −1 for 1961–1998. The lateral transport to the lithosphere and hydrosphere comprised 47 Tg C yr −1 (including charcoal), which is considered part of the “missing C sink.” The uncertainties (excluding unrecognized biases) of averages for the entire period are estimated to be in the range of ±5–8% and ±24% for major fluxes out/into the atmosphere and for net ecosystem exchange, respectively (a priori confidential probability of 0.9). If the impact of land-cover change is excluded, the average annual sink in 1961–1998, estimated by both pool- and flux-based methods, was 268 ± 94 and 272 ± 68 Tg C yr −1 , respectively. The reported results are in line with recent estimates for Northern Eurasia made by inverse modeling at the continental scale, if land classes other than forests contribute to the total sink of terrestrial vegetation. DOI: 10.1034/j.1600-0889.2003.00046.x

Negative emissions from BioEnergy use, carbon capture and sequestration (BECS)—the case of biomass production by sustainable forest management from semi-natural temperate forests

Abstract: In this paper, we show how nature oriented forestry measures in a typical temperate forest type in combination with bioenergy systems could lead to continuous and permanent removal of CO2 from the atmosphere. We employ a forest growth model suited for modeling uneven-aged mixed temperate stands and analyze the interaction with biomass energy systems that allow for CO2 removal and long-term sequestration in geological formations. On global scales this technological option to convert the global energy system from a CO2 emitter to a CO2 remover has been overlooked by both the science and policy communities. Removal of the major Greenhouse Gas (GHG) CO2 from the atmosphere is possible using biomass energy to produce both carbon neutral energy carriers (e.g., electricity and hydrogen) and, at the same time, offer a permanent CO2 sink by capturing carbon at the conversion facility and permanently storing it in geological formations. This technological option resolves the issues of permanence and saturation of biological sinks while at the same time this option respects the multiple benefits of sustaining diverse, healthy, and resilient forests. Our results indicate that a typical temperate forest in combination with capturing and long-term storage can permanently remove and on a continuous basis about 2.5 t C yr −1 ha −1 on a sustainable basis respecting the ecological integrity of the ecosystem.

IPCC Sres Revisited: A Response:

Abstract: Mr. Castles and Mr. Henderson have criticized the Special Report on Emissions Scenarios (SRES) and other aspects of IPCC assessments. It is claimed that the methodology is "technically unsound" because market exchange rates (MER) are used instead of purchasing power parities (PPP) and that the scenarios themselves are flawed because the GDP growth in the developing regions is too high. The response is: • The IPCC SRES reviews existing literature, most of which is MER based, including that from the World Bank, IEA and USDoE. • Scenarios of GDP growth are typically expressed as MER (the preferred measure for GDP growth, as opposed to PPP which is a preferred measure for assessing differences in economic welfare). • IPCC scenarios did include PPP-based scenarios, which Mr. Castles and Mr. Henderson have conveniently ignored. • Contrary to what Mr. Castles and Mr. Henderson claim, IPCC scenarios are consistent with historical data, including that from 1990 to 2000, and with the most recent near term (up to 20...

Spatial models of prebiotic evolution: soup before pizza?

Abstract: The problem of information integration and resistance to the invasion of parasitic mutants in prebiotic replicator systems is a notorious issue of research on the origin of life. Almost all theoretical studies published so far have demonstrated that some kind of spatial structure is indispensable for the persistence and/or the parasite resistance of any feasible replicator system. Based on a detailed critical survey of spatial models on prebiotic information integration, we suggest a possible scenario for replicator system evolution leading to the emergence of the first protocells capable of independent life. We show that even the spatial versions of the hypercycle model are vulnerable to selfish parasites in heterogeneous habitats. Contrary, the metabolic system remains persistent and coexistent with its parasites both on heterogeneous surfaces and in chaotically mixing flowing media. Persistent metabolic parasites can be converted to metabolic cooperators, or they can gradually obtain replicase activity. Our simulations show that, once replicase activity emerged, a gradual and simultaneous evolutionary improvement of replicase functionality (speed and fidelity) and template efficiency is possible only on a surface that constrains the mobility of macromolecule replicators. Based on the results of the models reviewed, we suggest that open chaotic flows ('soup') and surface dynamics ('pizza') both played key roles in the sequence of evolutionary events ultimately concluding in the appearance of the first living cell on Earth.

Unexpected discontinuities in life-history evolution under size-dependent mortality

Abstract: In many organisms survival depends on body size. We investigate the implications of size-selective mortality on life-history evolution by introducing and analysing a new and particularly flexible life-history model with the following key features: the lengths of growth and reproductive periods in successive reproductive cycles can vary evolutionarily, the model does not constrain evolution to patterns of either determinate or indeterminate growth, and lifetime number and sizes of broods are the outcomes of evolutionarily optimal life-history decisions. We find that small changes in environmental conditions can lead to abrupt transitions in optimal life histories when size-dependent mortality is sufficiently strong. Such discontinuous switching results from antagonistic selection pressures and occurs between strategies of early maturation with short reproductive periods and late maturation with long reproductive cycles. When mortality is size-selective and the size-independent component is not too high, selection favours prolonged juvenile growth, thereby allowing individuals to reach a mortality refuge at large body size before the onset of reproduction. When either component of mortality is then increased, the mortality refuge first becomes unattractive and eventually closes up altogether, resulting in short juvenile growth and frequent reproduction. Our results suggest a new mechanism for the evolution of life-history dimorphisms.

Anti-cancer selection as a source of developmental and evolutionary constraints

Abstract: Recently at least two papers have appeared that look at cancer from an evolutionary perspective. That cancer has a negative effect on fitness needs no argument. However, cancer origination is not an isolated process, but the potential for it is linked in diverse ways to other genetically determined developmental events, complicating the way selection acts on it, and through it on the evolution of development. The two papers take a totally different line. Kavanagh argues that anti-cancer selection has led to developmental constraints. Leroi et al. argue that cancer is a side-effect of recent evolutionary changes that usually will disappear over time through anti-cancer selection. Here we place the papers in a wider perspective, and in so doing discuss various alternative developmental links cancer may have together with their evolutionary implications.

Modeling knowledge: Model-based decision support and soft computations

Abstract: This chapter provides an overview of model-based support for modern decision making. It starts with discussing basic elements of decision making process, including characteristics of complex decision problems, concepts of rationality, and various requirements for model-based support at different stages of decision making process. Then the characteristics of models, and of modeling processes aimed at decision-making support for complex problems are presented. In this part guidelines for model specification and instantiation are illustrated by an actual complex model. This is followed by a discussion of modern methods of model analysis, which include a more detailed discussion of reference point optimization methods, and an outline of methods for sensitivity analysis, and of softly constrained inverse simulation. Finally, an overview of architecture of model-based decision support system is presented.

Universal Pensions in Mauritius: Lessons for the Rest of Us

Abstract: That the Government of Mauritius provides nearly every resident over the age of 60 with a non-contributory, basic pension is one of the best-kept secrets in the world. The scheme dates from 1950 and became universal in 1958, following abolition of a means test. Remarkably, introduction of a compulsory, contributory scheme for workers in the private sector appears to have strengthened the non-contributory regime without affecting its universality. This paper examines the past and future of non-contributory, universal pensions in Mauritius, and draws lessons that might be useful for other countries, especially those in the developing world.

Cooperation and competition in heterogeneous environments: The evolution of resource sharing in clonal plants

Abstract: Plant species show great variation in the degree of physiological integration between developmental units (modules). When this physiological integration is minimal, individual modules are self-supporting and compete with other modules. When there is greater physiological integration, modules remain physiologically connected and ‘cooperate’ by sharing resources like water, nutrients and photoassimilates taken up from their local environments. Thus, local differences in habitat quality can be diminished within a group of modules. Here we examine how the evolutionarily optimal amount of integration depends on habitat type – with habitats being characterized by the proportion of resource-rich and resource-poor sites and by the turnover rate between them. Two main questions are addressed: First, how does spatial heterogeneity influence natural selection for or against integration? Second, can adaptation, under reasonable ecological conditions, stabilize partial integration? A non-spatial version of the model, which assumes well-mixed populations, predicts the complete physiological independence of modules as the only evolutionarily stable outcome in any realistic habitat type. By contrast, a spatially explicit version of the model reveals the adaptive advantage of integration in typical high-risk habitats, where resource-rich sites are sparsely distributed in space and transient in time. We conclude that habitat diversity without spatial population structure is sufficient to explain the evolutionary loss of physiological integration. But only the additional consideration of spatial population structure can convincingly explain any backward transition and the stable existence of partial integration.

Speciation in multidimensional evolutionary space.

Abstract: Adaptive dynamics in two-dimensional phenotype space is investigated by computer simulation. The model assumes Lotka-Voltera-type competition and a stochastic mutation process. The carrying capacity has a single maximum in the origin of the strategy space and the competition coefficient decreases with strategy difference. Evolutionary branching, an asexual analog of adaptive speciation, is observed with suitable parameters. The branching at the singular point, which is a fixed point of the directional evolution, may occur into two or three, but not more, directions. Further branchings may occur after the initial separation. The probability of three-branching is studied as a function of several parameters. We conclude that the two-way branching is the predominant mode of adaptive speciation.

Long‐Term Population Decline in Europe: The Relative Importance of Tempo Effects and Generational Length

Abstract: It has recently been suggested that an end to further increases in the mean age of child-bearing in Europe (ending the negative tempo effect on fertility) would have a substantial effect on population dynamics in terms of slowing population aging and decline and weakening the negative momentum affecting population size over the coming decades On the other hand, stable population theory suggests that under sub-replacement fertility conditions, a longer mean length of generations implies slower shrinking, and thus a relatively larger population in the very long run This note compares the relative importance of the two effects analytically and with data for the 15-country European Union It also considers whether an increase in the mean age of childbearing will decrease the quantum of fertility This question is highly relevant in the context of the effects of possible policies aiming to influence the tempo of fertility rather than the quantum directly The results show that for the coming 200 years the effect of tempo changes clearly dominates, with the effect of a shorter mean length of generation only becoming visible thereafter Even small tempo-quantum interactions can overwhelm the generation-length effect

Planning for Future Energy Resources

Abstract: We disagree with M.I. Hoffert et al.'s (Advanced technology paths to global climate stability: Energy for a greenhouse planet, Reviews, 1 Nov., p.981) characterization of the IPCC Third Assessment Report's conclusion that known technological options could achieve a broad range of atmospheric stabilization levels, such as 550 ppm, 450 ppm or below over the next hundred years or more, as a misperception of technological readiness."...

A modelling assessment of acidification and recovery of European surface waters

Abstract: . The increase in emission of sulphur oxides and nitrogen (both oxidised and reduced forms) since the mid-1800s caused a severe decline in pH and ANC in acid-sensitive surface waters across Europe. Since c.1980, these emissions have declined and trends towards recovery from acidification have been widely observed in time-series of water chemistry data. In this paper, the MAGIC model was applied to 10 regions (the SMART model to one) in Europe to address the question of future recovery under the most recently agreed emission protocols (the 1999 Gothenburg Protocol). The models were calibrated using best available data and driven using S and N deposition sequences for Europe derived from EMEP data. The wide extent and the severity of water acidification in 1980 in many regions were illustrated by model simulations which showed significant deterioration in ANC away from the pre-acidification conditions. The simulations also captured the recovery to 2000 in response to the existing emission reductions. Predictions to 2016 indicated further significant recovery towards pre-acidification chemistry in all regions except Central England (S Pennines), S Alps, S Norway and S Sweden. In these areas it is clear that further emission reductions will be required and that the recovery of surface waters will take several decades as soils slowly replenish their depleted base cation pools. Chemical recovery may not, however, ensure biological recovery and further reductions may also be required to enable these waters to achieve the "good ecological status" as required by the EU Water Framework Directive. Keywords: Europe, acid-sensitive, waters, predictions, recovery, protocols

Determining Factors of the Czech Foreign Trade Balance: Structural Issues in Trade Creation

Abstract: Using panel data for 29 industries, we test alternative specifications of Czech export and import functions. The balance of trade is primarily influenced by the real exchange rate, aggregate demand and tariff changes. Reduced growth of the Czech economy after 1996 was an important factor that has kept the balance of trade at a sustainable level in the medium-term, contributing even to the appreciation of the real exchange rate. The secondary fundamental factors, relevant for structural adjustments, a sustainable trade balance and an equilibrium exchange rate, rest, however, on supply-side characteristics such as changes in endowments of physical and human capital, inflows of FDI and growing competitiveness of domestic production. We can argue that appreciation of the real exchange rate is a handicap to Czech exports, especially to exports to non-EU countries. Nevertheless, in the EU case, the appreciation of koruna was countervailed by tariff concessions, improved quality, switchover to commodities with higher contents of value added, gains associated with FDI and growing foreign demand absorption. At the same time, appreciation of the real exchange rate has significantly opened the Czech market to imports but the unconstrained import penetration remained blocked by the growing competitiveness of Czech products in costs, prices and quality.

Carbon trading with imperfectly observable emissions

Abstract: The Kyoto Protocol foresees emission trading but does not yet specify verification of (uncertain) emissions. This paper analyses a setting in which parties can meet their emission targets by reducing emissions, by investing in monitoring (reducing uncertainty of emissions) or by (bilaterally) trading permits. We derive the optimality conditions and carry out various numerical simulations. Our applications suggest that including uncertainty could increase compliance costs for the USA, Japan and the European Union. Central Europe and the Former Soviet Union might be able to gain from trading due to higher permit prices. Emissions trading could also lower aggregate uncertainty on emissions.

Learning Curve Analysis for Energy Technologies: Theoretical and Econometric Issues

Abstract: In bottom-up energy models endogenous technical change is introduced by implementing socalled energy technology learning rates, which specify the quantitative relationship between the cumulative experience of the technology and cost reductions. The main purpose of this paper is to survey and critically analyze the choice of modeling and estimation strategies in learning curve analyses of power generation costs. We identify and discuss a number of theoretical and econometric issues involved in the estimation of learning curves. These include, for instance, the presence of omitted variable bias and simultaneity. We illustrate the importance of these issues by employing panel data for wind power installations in four European countries, which are used to compare the results from different learning curve model specifications. The results illustrate that the empirical estimates of learning rates may differ significantly depending on the choice of model specification and econometric approach. The paper ends by outlining a number of recommendations for energy model analysts, who need to select appropriate energy technology learning rates from the empirical literature, or who choose to perform the empirical work themselves.