Exponential Population Growth and Doubling Times: Are They Dead or Merely Quiescent?

Exponential Growth and Doubling Times: Use of these popular population buzzwords of the last half of the twentieth century was fully justified by the growth rates of that period. However, those growth rates have now all but disappeared and so have the underlying reasons that those buzzwords made sense. Misuse of such expressions today costs credibility. Though the world's population growth certainly does remain vigorous and robust, creating many reasons for concern, nowhere today is growth projected as exponential. The essence of exponential growth is analyzed and distinguished from exponential curves, and non-exponential growth. Several types of current population growth are recognized, none being exponential. In periods of non-exponential growth, a Doubling Time calculated from a single annual growth rate is grossly erroneous and often absurd. Other standard measures of growth are needed. United Nations projections should include figures for percentage growth by 2025 and 2050.     

Managed growth and optimum population: Irreconcilable concepts

Managed growth is a politically popular rallying point which offends no faction by insisting upon nonnegotiable limits. Subscribers to this philosophy focus upon short-run accommodations to growth which apparently mitigate its physical consequences. Managed growthers react to longterm numerical projections with rejection, if not outright hostility. They may be more amenable to quality-of-life rationales for population limitation evolving from the biophilia hypothesis and ecopsychology. These theories claim that our species needs to exist in proximity to untrammelled wilderness and a natural environment for psychic health and creativity.     

Population in context: A typology of environmental driving forces

This paper presents a typology and qualitative model of causation for use in assessing the relative contributions of population growth to problems of pollution, lost biodiversity, and natural resource depletion. Population growth is placed in context as one of eight key driving forces that shape environmental quality today. It is treated primarily as an impact amplifier, along with technology. Root causes are traced to paradigmatic beliefs—especially anthropocentrism and contempocentrism—which find expression in unsustainable consumption patterns and designs of political economy.     

On Exponential Growth and Half-Lives: A Comment on Bermingham

A recent paper (hereafter referred to as the Paper), Bermingham (2003), presented what appeared to be an analytical review of current situation of declining population growth rates in many parts of the world. The Paper suggested that the increasing growth rates before about 1970 constituted exponential growth, but that the currently declining growth rates were not exponential growth. Hence, the paper asserted that we should not use the terms exponential growth and doubling times in describing the current situation. Many of the suggestions in the paper are contrary to established mathematics. These suggestions are examined here in some detail.     

Changing Industrial Metabolism: Methods for Analysis

Research in the field of industrial metabolism traditionally has been focused on measuring and describing physical flows of economic systems. The metabolism of economic systems, however, changes over time, and measuring material flows is insufficient to understand this process. Understanding the relation between economic activities and material flows can help to unravel the socio-economic causes of these physical flows. Three issues are addressed: The importance of spatial scales and trade flows, empirical analysis of relations between economic development and material flows, and treatment of behaviour of and interactions between stakeholders. For each of these issues, methods for analysis are suggested.     

Interstate migration of the US poverty population: Immigration “pushes” and welfare magnet “pulls”

This study evaluates the social and demographic structure of poverty migration during the 1985–90 period based on an analysis of recent census data. Particular attention is given to the roles of two policy-relevant factors that are proposed to be linked to poverty migration. The first of these is the role of immigration from abroad and its effect on the net out-migration of longer-term residents with below-poverty incomes, from States receiving the highest volume of immigrants. Such a response, it is argued, could result from job competition or other economic and social costs associated with immigration. The second involves the poverty population magnet effect associated with State welfare benefits (AFDC and Food Stamp payments) which has come under renewed scrutiny in light of the impending reform of the federal welfare program. The impact of both of these factors on interstate poverty migration is evaluated in a broader context that takes cognizance of other sociodemographic subgroups, and State-level attributes that are known to be relevant in explaining internal migration. This research employs an exceptionally rich data base of aggregate migration flows, specially tabulated from the full migration sample of the 1990 US census (based on the residence 5 years ago question). It also employs an analysis technique, the nested logit model, which identifies separately the push and pull effects of immigration, welfare benefits, and other State attributes on the migration process. Our findings are fairly clear. The high volume of immigration to selected US Statesdoes affect a selective out-migration of the poverty population, which is stronger for whites, Blacks and other non-Asian minorities as well as the least-educated. These results are consistent with arguments that internal migrants are responding to labor market competition from similarly educated immigrants. Moreover, we found that the impact of immigration occurs primarily as a push rather than a reduced pull. In contrast, State welfare benefits exert only minimal effects on the interstate migration of the poverty population—either as pulls or pushes, although some demographic segments of that population are more prone to respond than others. In addition to these findings, our results reveal the strong impact that a State's racial and ethnic composition exerts in both retaining and attracting migrants of like race and ethnic groups. This suggests the potential for a greater cross-state division in the US poverty population, by race and ethnic status.Data Used: 1990 US census tabulations of full migration (residence 5 years ago) sample. Note: Detailed 1990 census statistics on migration of the poverty and nonpoverty populations for individual states can be found in: William H. Frey Immigration and Internal Migration for US States: 1990 Census Findings by Poverty Status and Race, Population Studies CenterResearch Report No. 94-320.This research is supported by the University of Wisconsin Institute for Research on Poverty Small Grants Program and by NICHD grant No. R01 HD29725. The migration data for this paper were prepared at the Population Studies Center, University of Michigan from 1990 US Census files. The authors acknowledge Cathy Sun for computer programming assistance, and Ron Lue-Sang for preparing maps and graphics.     

Transnational Grannies: The Changing Family Responsibilities of Elderly African Caribbean-Born Women Resident in Britain

This paper explores the role and position of grandmothers in African-Caribbean families resident in Britain. The data used for this paper comes fromm a sample of 180 life-history interviews collected in 1995–1996 from three generations of Caribbean-origin people living in Britain and the Caribbean. Findings from this research suggest that African-Caribbean grandmothers resident in Britain have come to play a less active role within their immediate family compared to earlier historical periods. At the same time however, these grandmothers have come to take on a more a transnational emissary role for their family and kin located throughout North America and Europe. Caribbean-born grandmothers appear to be using more modern means for fulfilling certain traditional tasks like child shifting, story telling or acting as a social safety net. Using their agency African Caribbean-born grandmothers have been able to carve out new niches for themselves despite changes in family structure brought about by migration and settlement patterns in Britain.     

Environmental Migration and Sustainable Development in the Upper Reaches of the Yangtze River

This paper explores the demographic impacts of the implementation of the Grand Development in West China policies and environmental rehabilitation projects in the upper reaches of the Yangtze River. It analyses the interaction between the environmental reconstruction and environment-related migration in this region. The intertwined nature of environmental, ethnic, and poverty problems not only bears negatively upon the alleviation of poverty conducing to the accruement of wealth of the poverty-stricken population, but also hinders the rehabilitation of the environment. It brings forth some opinions regarding improving the capacity of regional sustainable development through environmental migration.     

Government fragmentation and suburban services: The equality of consumer choice

The predominant reform tradition of centralizing suburban government to deal with problems of inequality in the distribution of local services has been attacked recently by a new school of thought often labelled New Political Economists. This school believes that the existing structure of local government can maximize citizen choice by allowing citizens to shop around between the level and mix of public goods and services offered by alternate communities. The term polycentricity has been coined to describe this situation. Critics of polycentricity believe that the resulting quasi-market would be unfair to low and moderate income suburbanites. This paper examines the actual extent of choice in service levels available to different income groups located in the suburban ring of six metropolitan areas. The extent of inequality in choice between different income groups is measured and the implications of these findings for the conflict between polycentric and centralizing reformers is discussed.The research reported in this paper was funded by the National Science Foundation, Grant Number SOC7705600     

Do family caps reduce out-of-wedlock births? Evidence from Arkansas,Georgia, Indiana,New Jersey and Virginia

During the 1990s, 23 states implemented family cap policies as a means to reduce the incidence of out-of-wedlock births among welfare recipients. Using Current Population Survey data from 1989 to 1999, we examine the impact of family cap policies on the birth rates of single, less-educated women with children. We use the first five states that were granted waivers from the Department of Health and Human Services to implement family caps as natural experiments. Specifically, we compare trends in out-of-wedlock birth rates in Arkansas, Georgia, Indiana, New Jersey and Virginia to trends in states that did not implement family caps or any other waivers prior to the Personal Responsibility and Work Opportunity Reconciliation Act. We employ several techniques to increase the credibility of results from our natural experiment, such as the inclusion of multiple comparison groups, controls for differential time trends, and difference-in-difference-in-differences estimators. Our regression estimates generally do not provide evidence that family cap policies reduce the incidence of out-of-wedlock births among single, less-educated women with children.     

Native wage impacts of foreign labor: a random effects panel analysis

Natives often fear labor market competition of foreigners, as they may induce declining wages and rising unemployment as in the case of natives and immigrants being substitutes. However, there is also the potential that they are complements, producing positive wage and employment effects. This issue is examined in a framework with two types of labor, such that low qualified native and immigrant workers (blue collar), although substitutes for one another, are potentially complements to high qualified native workers (white collar). This is thought to accurately reflect the past West German immigration experience. Examining the wage functions of white and blue collar natives in a random effects panel model using a vast sample of micro data, we actually find that foreigners negatively affect the wages of Germans on the whole. Relatively small gains are made by white collar employees with less than 20 years experience, but these are outweighed by the larger negative effects experienced by blue collar employees.We wish to thank Don DeVoretz, Riccardo Faini, Andrea Ichino, and participants at the following 1993 conferences for their valuable comments where drafts of this paper were presented: The Economics of International Migration: Econometric Evidence at the University of Konstanz, Internationale Migration und Arbeitsmarkt der Schweizerischen Gesellschaft fur Statistik und Volkswirtschaftslehre at the University of St. Gallen, Adjustment Policies in Previously Centrally Planned Economies: Which Lessons from Developing Countries Experiences at the University of Brescia, and Congress of the European Society for Population Economics in Budapest. Substantial revisions were made following the valuable suggestions of two anonymous referees and the special issue editor Wolfgang Franz, for which we are grateful.     

Multiple-Scale Integrated Assessments of Societal Metabolism: Integrating Biophysical and Economic Representations Across Scales

The crucial challenge for integrated analyses of socioeconomic systems is keeping coherence in their multidimensional representation. Our approach describes the hierarchical structure of socioeconomic systems using the profile of allocation of human activity over a set of compartments defined at different hierarchical levels (e.g., whole countries, economic sectors, individual households). Compartments are characterized in terms of intensive variables (intensity of both exosomatic energy flows and added value flows per unit of human activity) and the extensive variable Total Human Activity population. In this way, relations of congruence across hierarchical levels can be used to link non-equivalent analyses. That is, changes in demographic variables, economic variables, technical coefficients, indices of environmental loading, institutional settings, and social aspirations are no longer independent of each-other even if described within different scientific disciplines.     

Three Centuries of Global Population Growth: A Spatial Referenced Population (Density) Database for 1700–2000

The Earths surface has changed considerably over the past centuries. Since the start of the Industrial Revolution in the early 1700s, humans from the Old World started to colonize the New World. The colonization processes lead to major changes in global land use and land cover. Large parts of the original land cover have been altered (e.g., deforestation), leading to extra emissions of GHGs to the atmosphere and enhancing global climate change. The spatial and temporal aspects are still not very well known. More and more global integrated environmental assessments concerning global sustainability require long time series of global change indicators, of which population is an important one. This study presents an update of the geo-referenced historical population maps for the period 1700–2000, part of the History Database of the Global Environment (HYDE), which can be used in integrated models of global change and/or global sustainability.     

Societal Metabolism and Multiple-Scale Integrated Assessment: Empirical Validation and Examples of Application

This paper presents empirical data to validate two points. (1) An integrated analysis of societal metabolism bridges an economic view of changes in socioeconomic systems with a biophysical representation of them. To obtain this check, it compares a biophysical indicator of development BEP with 24 traditional indicators of material economic development. The comparison covers a sample of 107 countries of the world, comprising more than 90% of the total world population (year 1993). (2) The concept of societal metabolism is useful to make biophysical analysts aware of constraints implied by economic viability and to make economic analysts aware of constraints implied by biophysical viability. To prove this point three practical examples of misunderstanding in the field of sustainability analysis are discussed.     

“Replacement Migration”: The UN Population Division on European Population Decline

The imminent decline of populations in Europe, Japan and South Korea has generated widespread apprehension, largely because of fears that there will not be enough working age people to support the elderly. The UN Population Division has seemed to endorse those fears by an analysis of the levels of immigration needed to provide a constant number or ratio of workers, and by writing of the need for a solution to population decline. On the other hand, smaller populations would be environmentally advantageous in those countries. They must return to replacement level fertility or risk replacement by other populations, but they would benefit if they reached stationarity at a smaller population level. The transition is manageable if a higher proportion of working age people go to work. Right now, though dependency ratios are supposedly highly favorable, most of those countries are plagued by high unemployment levels.     

Sexual and Reproductive Strategies Among Serbian Gypsies

This paper deals with a full range of sexual and reproductive behaviors among different tribes of Gypsies in Serbia. The examined traits include rates of fertility, mortality, age distribution, education, crime rates, and parental care. In addition, Gypsy traditions of culturally prescribed sexual behavior are also studied. It is found that Gypsy tribes employ different reproductive strategies, ranging from an extreme, for humans, r (reproductive) strategy to a more typical K (parental) strategy. The reasons bringing about these differences come from the Gypsies' readiness to adjust their behavior and reproduction in order to create the most favorable strategy in a given environment. This paper elucidates and contrasts the more typical r-selected Gypsies with a group of K-selected Gypsies living in a Serbian village.     

Migrant stock vs. lagged migrant flow as a determinant of migrant settlement. A comment on Anjomani and Hariri

In a recent contribution to this Journal Anjomani and Hariri present an interesting study of United States interstate migration which explicitly incorporates so-called flow diversion and flow creation effects. Their discussion and evaluation of the model, however, are marred by several factors. This paper contrasts the roles of migrant stock and lagged migration in migration analysis and then addresses (a) the problems encountered when the family-friends effect is proxied with measures of lagged migrant flows, (b) the problem of using a two-period lagged value of earlier migrant flow as an explanatory variable, and (c) this paper suggests an alternative method of correcting the Anjomani-Hariri model's problems with multicollinearity.The author is grateful to Walter J. Wadycki and to David A. Macpherson for helpful comments and suggestions. The author, of course, bears full responsibility for all errors that remain. This research benefited from a grant from the Miami University Committee on Faculty Research.     

Macro-effects of changes in household preferences for children

The basic ideas underlying the analysis in this paper are that family size can be viewed as an economic life cycle decision and that there are decision trade-offs among fertility, consumption, and leisure. A micromodel of life cycle choice is developed and embedded in an economic-demographic macromodel. The macromodel is then used in a series of computer experiments to assess the effects on the population and the economy of changes in household preferences for children. The experiments include factual and counterfactual simulations of Canadian historical demographic experience and simulations of alternative future scenarios. The analysis and conclusions have general relevance for countries that have been through a fertility boom-and-bust sequence.We are grateful for the support received from Health and Welfare Canada's Review of Demography and Its Implications for Social and Economic Policy and from the Social Sciences and Humanities Research Council of Canada. We are grateful also to Christine H. Feaver, who carried out the computer-related aspects of the work on which this paper is based.     

Interpreting demographic effects in duration analyses of first birth intervals

Estimated demographic effects in proportional hazard models of first birth intervals could reflect time-invariant differences in the risk of a birth, or differences in the timing of a shift in the risk, or both. This paper attempts to distinguish between these possibilities. The procedure is to estimate a more general model than the proportional hazard specification, in which the evolution of the risk of a birth can differ with demographic characteristics. The proportional hazard specification is nested within this more general model. Consequently, the consistency of the data with the risk or the timing interpretation of demographic effects can be tested. The data studied do not lead to a rejection of the proportional hazard specification.Department of Economics, University of Pennsylvania. The initial stage of this research was supported by a National Science Foundation Graduate Fellowship. I have benefited from insightful comments from David Bloom, Andrew Foster, Zvi Griliches, V. Joseph Hotz, Duncan Thomas, anonymous referees, and participants in seminars at Harvard University and the University of Pennsylvania, and in the Economic Demography sessions of the 1988 Population Association of America annual meetings. Any remaining errors are my own.     

Reflections on sustainability,population growth,and the environment

The related terms, sustainable and sustainability, have become popular and are used to describe a wide variety of activities which are generally ecologically laudable. At the same time, the term compromise is heard more frequently because the needs of the environment often are in conflict with the needs of humans. A brief examination of the question of compromise shows that a series of ten compromises, each of which saves 70% of the remaining environment, results in the saving of only 3% of the environment. Judging from the ways in which the terms sustainable and sustainability are used, their definitions are not very precise, especially when compromises are involved. An attempt is made here to give firm definition to these terms and to translate the definition into a series of laws and hypotheses which, it is hoped, will clarify the implications of their use. These are followed by a series of observations and predictions that relate to sustainability.