Showing papers by "International Institute for Applied Systems Analysis published in 2002"

Volunteering as Red Queen Mechanism for Cooperation in Public Goods Games

Abstract: The evolution of cooperation among nonrelated individuals is one of the fundamental problems in biology and social sciences. Reciprocal altruism fails to provide a solution if interactions are not repeated often enough or groups are too large. Punishment and reward can be very effective but require that defectors can be traced and identified. Here we present a simple but effective mechanism operating under full anonymity. Optional participation can foil exploiters and overcome the social dilemma. In voluntary public goods interactions, cooperators and defectors will coexist. We show that this result holds under very diverse assumptions on population structure and adaptation mechanisms, leading usually not to an equilibrium but to an unending cycle of adjustments (a Red Queen type of evolution). Thus, voluntary participation offers an escape hatch out of some social traps. Cooperation can subsist in sizable groups even if interactions are not repeated, defectors remain anonymous, players have no memory, and assortment is purely random.

Forest carbon sinks in the northern hemisphere

Abstract: There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary greatly. National forest inventories provide strong, measurement-based constraints on the magnitude of net forest carbon uptake. We brought together forest sector C budgets for Canada, the United States, Europe, Russia, and China that were derived from forest inventory information, allometric relationships, and supplementary data sets and models. Together, these suggest that northern forests and woodlands provided a total sink for 0.6–0.7 Pg of C per year (1 Pg = 1015 g) during the early 1990s, consisting of 0.21 Pg C/yr in living biomass, 0.08 Pg C/yr in forest products, 0.15 Pg C/yr in dead wood, and 0.13 Pg C/yr in the forest floor and soil organic matter. Estimates of changes in soil C pools have improved but remain the least certain terms of the budgets. Over 80% of the estimated sink occurred in one-third of the forest area, in temperate regions affected by fire suppression, agricultural abandonment, and plantation forestry. Growth in boreal regions was offset by fire and other disturbances that vary considerably from year to year. Comparison with atmospheric inversions suggests significant land C sinks may occur outside the forest sector.

Measuring probabilistic reaction norms for age and size at maturation

Abstract: We present a new probabilistic concept of reaction norms for age and size at maturation that is applicable when observations are carried out at discrete time intervals. This approach can also be used to estimate reaction norms for age and size at metamorphosis or at other ontogenetic transitions. Such estimations are critical for understanding phenotypic plasticity and life-history changes in variable environments, assessing genetic changes in the presence of phenotypic plasticity, and calibrating size- and age-structured population models. We show that previous approaches to this problem, based on regressing size against age at maturation, give results that are systematically biased when compared to the probabilistic reaction norms. The bias can be substantial and is likely to lead to qualitatively incorrect conclusions; it is caused by failing to account for the probabilistic nature of the maturation process. We explain why, instead, robust estimations of maturation reaction norms should be based on logistic regression or on other statistical models that treat the probability of maturing as a dependent variable. We demonstrate the utility of our approach with two examples. First, the analysis of data generated for a known reaction norm highlights some crucial limitations of previous approaches. Second, application to the northeast arctic cod (Gadus morhua) illustrates how our approach can be used to shed new light on existing real-world data.

Environmental variation, vegetation distribution, carbon dynamics and water/energy exchange at high latitudes

Abstract: The responses of high latitude ecosystems to global change involve complex interactions among environmental variables, vegetation distribution, carbon dynamics, and water and energy exchange. These responses may have important consequences for the earth system. In this study, we evaluated how vegetation distribution, carbon stocks and turnover, and water and energy exchange are related to environmental variation spanned by the network of the IGBP high latitude transects. While the most notable feature of the high latitude transects is that they generally span temperature gradients from southern to northern latitudes, there are substantial differences in temperature among the transects. Also, along each transect temperature co-varies with precipitation and photosynthetically active radiation, which are also variable among the transects. Both climate and disturbance interact to influence latitudinal patterns of vegetation and soil carbon storage among the transects, and vegetation distribution appears to interact with climate to determine exchanges of heat and moisture in high latitudes. Despite limitations imposed by the data we assembled, the analyses in this study have taken an important step toward clarifying the complexity of interactions among environmental variables, vegetation distribution, carbon stocks and turnover, and water and energy exchange in high latitude regions. This study reveals the need to conduct coordinated global change studies in high latitudes to further elucidate how interactions among climate, disturbance, and vegetation distribution influence carbon dynamics and water and energy exchange in high latitudes.

Evolutionary suicide and evolution of dispersal in structured metapopulations

Abstract: We study the evolution of dispersal in a structured metapopulation model. The metapopulation consists of a large (infinite) number of local populations living in patches of habitable environment. Dispersal between patches is modelled by a disperser pool and individuals in transit between patches are exposed to a risk of mortality. Occasionally, local catastrophes eradicate a local population: all individuals in the affected patch die, yet the patch remains habitable. We prove that, in the absence of catastrophes, the strategy not to migrate is evolutionarily stable. Under a given set of environmental conditions, a metapopulation may be viable and yet selection may favor dispersal rates that drive the metapopulation to extinction. This phenomenon is known as evolutionary suicide. We show that in our model evolutionary suicide can occur for catastrophe rates that increase with decreasing local population size. Evolutionary suicide can also happen for constant catastrophe rates, if local growth within patches shows an Allee effect. We study the evolutionary bifurcation towards evolutionary suicide and show that a discontinuous transition to extinction is a necessary condition for evolutionary suicide to occur. In other words, if population size smoothly approaches zero at a boundary of viability in parameter space, this boundary is evolutionarily repelling and no suicide can occur.

Changing Trends in Sulfur Emissions in Asia: Implications for Acid Deposition, Air Pollution, and Climate

Abstract: In the early 1990s, it was projected that annual SO2 emissions in Asia might grow to 80−110 Tg yr-1 by 2020. Based on new high-resolution estimates from 1975 to 2000, we calculate that SO2 emissions in Asia might grow only to 40−45 Tg yr-1 by 2020. The main reason for this lower estimate is a decline of SO2 emissions from 1995 to 2000 in China, which emits about two-thirds of Asian SO2. The decline was due to a reduction in industrial coal use, a slow-down of the Chinese economy, and the closure of small and inefficient plants, among other reasons. One effect of the reduction in SO2 emissions in China has been a reduction in acid deposition not only in China but also in Japan. Reductions should also improve visibility and reduce health problems. SO2 emission reductions may increase global warming, but this warming effect could be partially offset by reductions in the emissions of black carbon. How SO2 emissions in the region change in the coming decades will depend on many competing factors (economic grow...

Estimating Reaction Norms for Age and Size at Maturation with Reconstructed Immature Size Distributions: A New Technique Illustrated by Application to Northeast Arctic Cod

Abstract: Reaction norms for age and size at maturation describe the probability of immature fish maturing at a certain age and size. Knowledge of such reaction norms is increasingly important, both for observing and understanding changes in maturation and for calibrating size- and age-structured population models. Estimating the reaction norms for age and size at maturation by logistic regression requires data on the size and age distribution of immature and maturing fish. To permit such estimation when measurements of the size and age distribution of immature fish are not available, the information can be reconstructed by means of a back-projection procedure. For the reconstruction, only the size and age distribution of maturing fish, or first-time spawners, together with the age-dependent proportion of mature fish, given in the form of maturity ogives, have to be known. The method of Gulland (1964) is used to generate maturity ogives in the absence of data on immature fish. The robustness of the estimation method is demonstrated by analysing artificial data generated with a known reaction norm. Application of the reconstruction method to a set of measurements on Northeast Arctic cod (Gadus morhua) collected between 1933 and 1944 illustrates how the approach allows new information to be extracted from real data. 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd.

Determinants of human population growth.

Abstract: The 20th century has seen unprecedented growth of the human population on this planet. While at the beginning of the century the Earth had an estimated 1.6 billion inhabitants, this number grew to 6.1 billion by the end of the century, and further significant growth is a near certainty. This paper tries to summarize what factors lie behind this extraordinary expansion of the human population and what population growth we can expect for the future. It discusses the concept of demographic transition and the preconditions for a lasting secular fertility decline. Recent fertility declines in all parts of the world now make it likely that human population growth will come to an end over the course of this century, but in parts of the developing world significant population growth is still to be expected over the coming decades. The slowing of population growth through declining birth rates, together with still increasing life expectancy, will result in a strong ageing of population age structure. Finally, this paper presents a global level systematic analysis of the relationship between population density on the one hand, and growth and fertility rates on the other. This analysis indicates that in addition to the well-studied social and economic determinants, population density also presents a significant factor for the levels and trends of human birth rates.

Dynamics of Russian Forests and the Carbon Budget in 1961–1998: An Assessment Based on Long-Term Forest Inventory Data

Abstract: Development trends of Russian forests and their impact on the global carbon budget were assessed at the national level on the basis of long-term forest inventory data (1961–1998). Over this period, vegetation of Russian forest lands are estimated as a carbon sink, with an annual average level of carbon sequestration in vegetational organic matter of 210 ± 30 Tg C · yr−1 (soil carbon is not considered in this study), of which 153 Tg C · yr−1 were accumulated in live biomass and 57 Tg C · yr−1 in dead wood. The temporal variability of the sink is very large; for the five-year averages used in the analysis, the C sequestration varies from about 60 to above 300 Tg C· yr−1. It is shown that long-term forest inventory data could serve as an important information base for assessing crucial indicators of full carbon accounting of forests.

Boreal forest fires in Siberia in 1998: Estimation of area burned and emissions of pollutants by advanced very high resolution radiometer satellite data

Abstract: [1] The NOAA 12 advanced very high resolution radiometer detected extensive forest fires in boreal Siberia and northern Mongolia during April through October 1998, a year of extremely dry weather, in particular, in the Russian Far East. Analysis of the satellite data has been carried out to estimate the area burned and gaseous emissions to the atmosphere from the point of view of ozone precursors. The fires started in western and eastern Siberia and moved eastward during the summer, until they were concentrated in the Russian Far East, near Sakhalin Island, in the period of July to October. Satellite observations for the fire season and detailed characteristics of terrestrial vegetation in the form of multilayer geographic information systems were used along with published emission factors from similar fires to calculate the gaseous emissions. The total area burned is estimated to be 1.1 × 107 ha with 350 Tg of biomass consumed and 176 Tg of carbon released into the atmosphere. The carbon released into the atmosphere is calculated to contribute 516 Tg of CO2, 50 Tg of CO, 1.6 Tg of CH4, 1.1 Tg of NMHC, and 9.5 Tg of C particles as smoke. In addition, we estimate that 1.8 Tg of NOx (as NO2) were released.

Ecological bistability and evolutionary reversals under asymmetrical competition

Abstract: How does the process of life-history evolution interplay with population dynamics? Almost all models that have addressed this question assume that any combination of phenotypic traits uniquely determine the ecological population state. Here we show that if multiple ecological equilibria can exist, the evolution of a trait that relates to competitive performance can undergo adaptive reversals that drive cyclic alternation between population equilibria. The occurrence of evolutionary reversals requires neither environmentally driven changes in selective forces nor the coevolution of interactions with other species. The mechanism inducing evolutionary reversals is twofold. First, there exist phenotypes near which mutants can invade and yet fail to become fixed; although these mutants are eventually eliminated, their transitory growth causes the resident population to switch to an alternative ecological equilibrium. Second, asymmetrical competition causes the direction of selection to revert between high and low density. When ecological conditions for evolutionary reversals are not satisfied, the population evolves toward a steady state of either low or high abundance, depending on the degree of competitive asymmetry and environmental parameters. A sharp evolutionary transition between evolutionary stasis and evolutionary reversals and cycling can occur in response to a smooth change in ecological parameters, and this may have implications for our understanding of size-abundance patterns.

Carbon in Russian Soils

Abstract: Soil carbon densities and pools have been estimated for Russia. The estimate was derived from the generalized version of the soil map of the country at the scale 1:2.5 million (Fridland, 1988), which has been designated a countrywide standard. At the pre-developed stage, the soils in Russia captured about 373 Pg of organic and 75 Pg of inorganic C in the 0–2.0 m layer. Organic C is intensively accumulated in the topsoil. Inorganic C tends to concentrate in deep soils and is of non-pedogenic origin. The mass of organic matter is captured in the tundra, pre-tundra, and the northern and middle taiga of Russia. Anthropogenic impacts have led to a loss of about 5 Pg of C in the 0–1.0 m layer, which is some 2% of the total C content in Russian soils. From this amount, the topsoil of cropland has lost 2.6 Pg (20% of the initial C content in soils), including 0.4 Pg caused by erosion. The deep soil (0.3–1.0 m) of cropland has lost 1 Pg. Some 0.5 Pg of C are removed from the topsoil (7%) and 0.6 Pg by the deep soil from pastures. Forest soils have roughly lost about 0.3 Pg of C due to the decline of C input into soils caused by various disturbances. The predicted climate warming is expected to enhance the C sequestration by soil in Russia.

The evolution of self-fertilization in density-regulated populations

Abstract: The evolution of selfing in hermaphrodites has been studied to reveal the demographic conditions that lead to intermediate selfing rates. Using a demographic model based on Ricker-type density regulation, we assume first that, independent of population density, inbred individuals survive less well than outbred individuals and second, that inbred and outbred individuals differ in their competitive abilities in density-regulated populations. The evolution of selfing, driven by inbreeding depression and the cost of outcrossing, is then analysed for three fundamentally different demographic scenarios: stable population densities, deterministically varying population densities (resulting from cyclical or chaotic population dynamics) and stochastic fluctuations of carrying capacities (resulting from environmental noise). We show that even under stable demographic conditions evolutionary outcomes are not confined to either complete selfing or full outcrossing. Instead, intermediate selfing rates arise under a wide range of conditions, depending on the nature of competitive interactions between inbred and outbred individuals. We also explore the evolution of selfing under deterministic and stochastic density fluctuations to demonstrate that such environmental conditions can evolutionarily stabilize intermediate selfing rates. This is the first study, to our knowledge, to consider in detail the effect of density regulation on the evolution of selfing rates.

A Methodology to Estimate Changes in Statistical Life Expectancy Due to the Control of Particulate Matter in Air Pollution

Abstract: Studies in the United States have shown that those living in less polluted cities live longer than those living in more polluted cities. After adjustments for other factors, an association remained between ambient concentrations of fine particles and shorter life expectancy. This paper presents a methodology to apply the findings of these epidemiological studies to scenarios to control fine particulate matter in Europe and to estimate the resulting losses in statistical life expectancy that can be attributed to particulate matter pollution. Calculations are carried out for all of Europe with a 50*50 km resolution, distinguishing higher PM2.5 levels in urban areas. The methodology uses population statistics and projections from the United Nations, and applies changes in mortality risk identified by the epidemiological studies to the life tables for the individual countries. The preliminary implementation suggests that, for constant 1990 pollution levels, statistical life expectancy is reduced by approximately 500 days (95 percent confidence interval ranging from 168 - 888 days). By 2010, the control measures presently decided for emissions of primary particles and the precursors of secondary aerosols are expected to reduce these losses to about 280 days (94 -497), while the theoretical maximum technically feasible emission reductions could bring reduced life expectancy below 200 (65 -344) days. While the quantifications in this study must be considered as preliminary, the methodology will allow the introduction of health impacts from fine particulate matter into a multi-pollutant/multi-effect framework so that control measures can be explored taking full account of their ancillary benefits for acidification, eutrophication and ground-level ozone.

Environmental impact of photovoltaic electrification in rural areas

Abstract: The environmental impact of photovoltaics (PV) is discussed to ascertain how well it can aid solving the dual problem of meeting the demand for electricity in rural areas and of mitigating the energy-related environmental problems. It is noted that all emissions from PV are indirect and result mainly from the energy used in producing PV equipment. They are compared with the emissions that can be offset by the use of PV. It is concluded that PV is environmentally benign, and in some cases the cheapest way of providing electricity in rural areas. Nevertheless, its currently high costs and small electric capacity mean that there are cheaper and more effective methods for solving environmental problems in the short run. It is observed, however, that the costs of emission abatement are much higher if only the emissions from existing energy uses that are replaced by PV are considered than if the emissions and costs of alternative power production methods that are offset are also included. In the longer run, PV is seen to have very high potential for growth, lower costs, and environmental benefits. Issues affecting the success of PV dissemination in rural areas of developing countries are discussed, and policy suggestions are given.

Carbon Dioxide Emission from Soils of Russian Terrestrial Ecosystems

Abstract: In order to estimate the total, heterotrophic and autotrophic respiration of Russian soils, a special soil respiration database (SRDB) was compiled based on published results and the author's own measurements. The SRDB includes 95 regional studies and contains 375 records. It has been found that the contribution of the summer CO2 flux to the annual carbon dioxide flux (ACDF) is adequately quantified by linear and polynomial regressions. The total soil respirations of individual ecosystems were computed based on these models and the measured summer CO2 fluxes. The mean and median values of root respiration by five aggregated land classes were estimated, based on experimental data. By using the obtained results we calculated the heterotrophic and autotrophic components of the total CO2 by land classes. The total, heterotrophic and autotrophic ACDF from Russian soils were assessed based on the distribution of areas of different land classes within the total area of soil units. The total, heterotrophic and autotrophic ACDF from Russian soils were estimated to be 5.67, 2.78 and 2.89 PgCy-1, respectively. The maps of total, heterotrophic and autotrophic soil respiration were developed using a geographic information system (GIS) approach. The summarized heterotrophic CO2 flux and mean weighted heterotrophic respiration of soils by different land use categories and location in different bio-climatic zones were computed using a GIS approach, based on a heterotrophic soil respiration map, a land use/land cover map and a vegetation map. The results obtained contribute to current understanding of the full terrestrial biota carbon balance of Russia.

Repeated Play of Potential Games

Abstract: So-called potential functions are important, prominent, and common to many diverse fields, including optimization, dynamic processes, and physics. Monderer and Shapley have added a class of noncooperative games to that list. In the present paper, their notion is extended and repeated play of such games is considered. A unified convergence analysis is provided and procedures that account for efficiency or viability are shown.

Optimal trajectories of the innovation process and their matching with econometric data

Abstract: A dynamical model of optimal economic growth is used for the comparison of catalogs of real econometric data and synthetic growth scenarios. The model is calibrated on a database of the Tokyo Institute of Technology. Special attention is paid to the aggregated data of the Japanese manufacturing industry in the period 1960-92. A description of an algorithm modeling optimal trends in the technological dynamics is given.

Technological Progress towards Sustainable Development

Abstract: The purpose of this paper is twofold First, to present an analysis of a comprehensive set of global energy scenarios that has been undertaken to identify key energy technologies for achieving sustainable development Secondly, to describe tools that could aid policy makers using insights in the dynamics of technological progress to promote the development of promising technologies throughresearch and development (R&D) and procurement As an operational working definition of sustainable development we use the following four criteria: (1) Economic growth sustains throughout the whole time horizon; (2) socio-economic inequity among world regions is reduced "significantly" during this century; (3) reserves-to-production (R/P) ratios of exhaustible primary energy carriers do not decrease substantially from today's values; and (4) short- to medium-term environmental impacts (eg, acidification) are reduced towards meeting critical loads and carbon emissions at the end of the century are below today's levels Applying these criteria in an analysis of a representative set of global economy-energy-environment scenarios shows that in sustainable-development scenarios, hydrogen fuel cells and solar photovoltaic cells emerge as key technologies in the long run Natural gas technologies, in particular fuel cells and combined-cycle power plants, could provide for an efficient medium-term transition to these key technologies The question then becomes which policies can promote the development of these technologies We think that an important tool to tackle this question is provided by an improved concept of technological learning According to that concept, technological progress, expressed as specific technology cost, is a regular function of not only cumulative installed capacity but also of R&D expenditures This tool can assist in determining how much money should be spent for which energy technology on procurement (capacity expansion) and how much money for R&D The results of first model runs aiming at eventually formulating policy guidance are presented

Methane as an energy source for the 21st century

Abstract: Today, fossil fuels supply about 80% of global primary energy. The consequences are severe for human health from indoor and regional air pollution, acidification due to sulphur and nitrogen oxide emissions and climate change due to rapidly growing greenhouse gas emissions. Therefore, there is a clear need to improve the efficiency and the environmental compatibility of fossil technologies, shift to fossil energy sources with lower environmental impacts such as natural gas, or shift away from fossil energy use to renewable sources and nuclear power. This is an especially challenging prospect for the rapidly developing countries of Asia. Wider use of natural gas and electricity in Asia would help promote higher energy efficiencies, better quality of energy services and substantially lower environmental impacts especially at the level of energy end use. Such a transition would require new continental-scale infrastructures including natural gas and electricity grids and distribution systems.

Dynamic Model of Market of Patents and Equilibria in Technology Stocks

Abstract: The paper presents a dynamic model of trading on market of patents. It is assumed that each firm participating in market produces its own technologies, whereas its manufacturing sector utilizes both originally produced technologies and those produced in other firms. The firms are therefore interdependent through the technology stocks used in manufacturing, which provides a basis for the emergence of market of patents. In our model, a firm has three actions in market, prior announcement, offering payoffs, and making decisions. Three-stage trading is repeated periodically, and thus, drives the evolution of the firms' technology stocks. We show that, under reasonable assumptions, the proposed pattern allows the firms to act so that, first, their individual decisions are subjectively best in every period of trading, and second, current combinations of their technology stocks gradually approach a state which maximizes the total profit of the firms' community. An important feature of the model is that the described market operations imply the minimum exchange in individual information.