Population,Development and Global Warming: Averting the Tragedy of the Climate Commons

Carbon emissions from fossil fuel use and other human activity are predicted to cause a significant warming of the global climate, according to a growing consensus of scientists. Global warming would have substantial negative effects on the world environment and economy. Human population and economic growth continue to drive both energy use and carbon emissions. While the developed countries are the largest source of present and past emissions, developing countries are rapidly catching up. China will probably surpass the United States as the largest carbon emitter early in the next century. The global warming treaty signed in Rio in 1992 relies entirely on voluntary emission caps for developed countries and has had little or no apparent effect on emissions. Much stronger steps must be taken to avoid or lessen potential climate change. A globally determined but nationally imposed carbon tax should be adopted to internalize the future costs of carbon emissions into the present cost of fossil fuel and other carbon sources. This would allow the maximum use of free market forces and individual choice to determine how carbon emission reductions are achieved. In addition, national emission caps for all countries should be established. International trade mechanisms can be used to support universal implementation of these measures. Where possible, global warming policy should include strong but equitable incentives for sustainable development and population stabilization, important goals in themselves regardless of the extent of future climate change.     

人口与消费对二氧化碳排放的动态影响——基于变参数模型的实证分析

近年来,随着全球气候的不断变暖,二氧化碳减排问题已经引起了世界性的关注。中国作为世界上最大的碳排放国,必须逐步降低经济发展过程中的碳排放。基于此,利用1978～2009年的相关数据和变参数模型,分析了人口数量和居民消费对我国二氧化碳排放的动态影响。结果表明,人口、消费与二氧化碳排放之间存在长期稳定的关系,二者对碳排放均有比较显著的影响。从总体来看,人口对碳排放的影响弹性要高于消费对碳排放的弹性,但是近年来两者之间的差距越来越小,说明消费对二氧化碳排放的影响力日益增大;随着时间波动,人口与消费对碳排放的影响弹性会呈现规律性的变化,并且可以将其划分为三个明显的阶段。依据上述结论,文章提出了相关政策建议,以减少由人口和消费带来的二氧化碳排放。     

On Development,Demography and Climate Change: The End of the World as We Know it?

This paper comments on the issue of global warming and climate change, in an attempt to provide fresh perspective. Essentially, five main arguments are made. First, that the process of modern economic development has been based on the burning of fossil fuels, and that this will continue to apply for the foreseeable future. Second, that in large part due to momentum in economic and demographic processes, it is inevitable that there will be a major rise in atmospheric CO₂ during the present century. Third, that available data on global temperatures suggest strongly that the coming warming will be appreciably faster than anything that humanity has experienced during historical times. Moreover, especially in a system that is being forced, the chance of an abrupt change in climate happening must be rated as fair. Fourth, that while it is impossible to attach precise probabilities to different scenarios, the range of plausible unpleasant climate outcomes seems at least as great as the range of more manageable ones. The consequences of future climate change may be considerable; indeed, they could be almost inconceivable—with several negative changes occurring simultaneously and to cumulative adverse effect. There is an urgent need to improve ways of thinking about what could happen. Fifth, the paper maintains that the human response to other difficult ‘long’ threats—such as that posed by HIV/AIDS—reveals a broadly analogous sequence of social reactions (e.g. denial, avoidance, recrimination) to that which is unfolding with respect to carbon emissions and climate change. Therefore the view expressed here is that major behavioral change to limit world carbon emissions is unlikely in the foreseeable future, and that the broad sway of future events is probably now set to run its course.This paper is a personal assessment of what is occurring with respect to the subject of global warming and climate change. Nevertheless it is an attempt to examine the topic objectively. The paper tries to concentrate on the essentials—from both the social and the environmental sciences—and, quite deliberately, it presents basic data on the subject for the reader's own consideration. The paper's subtitle is taken from a television program broadcast in January 2005 as part of UK Channel Four's War on Terra season. I thank Tim Forsyth, Chris Wilson, and especially Brian O'Neill for their help and advice. However, and most certainly, the usual disclaimer applies.     

The Leverage of Demographic Dynamics on Carbon Dioxide Emissions: Does Age Structure Matter?

This article provides a methodological contribution to the study of the effect of changes in population age structure on carbon dioxide (CO₂) emissions. First, I propose a generalization of the IPAT equation to a multisector economy with an age-structured population and discuss the insights that can be obtained in the context of stable population theory. Second, I suggest a statistical model of household consumption as a function of household size and age structure to quantitatively evaluate the extent of economies of scale in consumption of energy-intensive goods, and to estimate age-specific profiles of consumption of energy-intensive goods and of CO₂ emissions. Third, I offer an illustration of the methodologies using data for the United States. The analysis shows that per-capita CO₂ emissions increase with age until the individual is in his or her 60s, and then emissions tend to decrease. Holding everything else constant, the expected change in U.S. population age distribution during the next four decades is likely to have a small, but noticeable, positive impact on CO₂ emissions.     

The Stern Review on the Economic Effects of Climate Change

In a study of the economics of climate change commissioned by the British government, released on 30 October, the former World Bank chief economist Sir Nicholas Stern presents a vigorously argued case for early curtailment of greenhouse gas emissions and proposes mitigation strategies that appear to offer highly favorable benefit‐cost ratios. An excerpt from the Executive Summary of the Stern Review, concerned with the nature and magnitude of the deleterious economic consequences of anticipated climate change, is printed below. The principal scientific reviews of knowledge of climate change, its consequences, and mitigation strategies are the (roughly) quinquennial reports of the Intergovernmental Panel on Climate Change (IPCC)—the work of hundreds of lead authors, subjected in turn to elaborate peer review and line‐by‐line scrutiny by interested governments. They represent a broad, though not total, expert consensus. The third IPCC assessment was issued in 2001; the fourth, already in draft, will be released next year. The Stern Review draws heavily on this scientific underpinning, but goes further than the IPCC exercise in computing economic values for the projected changes and costing out remedial policy responses. More forthright in style and emphatic in its conclusions, it reads as a resounding call to international action. The Review explores the implications of atmospheric concentrations of carbon dioxide and other greenhouse gases being capped at 550ppm (parts per million), double the preindustrial level, an objective it argues is feasible. That concentration would be reached by 2050 at current emission rates, or by 2035 if emissions rise as expected. The resulting warming, it believes, would be 2‐5°C, roughly in accord with the IPCC's third‐assessment estimates (see the Documents section of PDR 27, no. 1 for the IPCC projections). The positive feedbacks identified in some recent studies, generated by processes such as release of methane from permafrost, could lead to still higher temperatures. The forecast effects described are by now familiar, though no less grim for being so: species extinctions, expanding disease zones, reductions in surface water availability, coastal flooding, ocean acidification, and so on. The Review translates these effects into economic losses, adjusting for risk, using Monte Carlo simulation applied to an integrated assessment model (the so‐called PAGE 2002 model). The exercise, requiring many heroic—and often contestable—assumptions, produces the most quoted figures in the report: that climate change “will reduce welfare by an amount equivalent to a reduction in consumption per head of between 5 and 20%”—now and into the future. The absolute magnitude of those projected economic losses is made arbitrarily large by their permanence. Typical benefit‐cost calculations applied to appraisal of development projects convert such long‐term trajectories into a present value using a discount rate comparable to a market interest rate or some (lower) assumed rate of time preference. The Stern Review, however, argues that any discounting is ethically inappropriate for this global issue: “if a future generation will be present, we suppose that it has the same claim on our ethical attention as the current one” (p. 31). The only exception is an allowance for the possibility that future generations are not present—through human extinction—which is held to justify a minuscule discount rate of 0.1 percent per annum (p. 161). The percentage economic losses from climate change appear less daunting if set against the recent pace of expansion in the world economy. Real per capita income growth since 1990 has averaged about 1.5 percent per year worldwide, and about 3 percent in developing countries. In such a regime, a 5 percent one‐time drop to a lower expansion path is no more than a two‐ or three‐year delay in attaining a given income level. For China and India, whose economies are doubling in size each decade, even a 20 percent reduction in income would be a mere hiccough on the path to affluence—hardly enough to motivate major shifts in lifestyle ambitions. The dire repercussions on global environments of a greenhouse warming at the upper end of the forecast range are poorly captured by those percentages. Demography has a marginal place in the Review. The underlying IPCC emission scenarios incorporate expected population growth, using the UN medium projections. Many of the climate‐change effects incur costs that are similarly magnified by population growth. One‐sixth of the world's population is “threatened” by water scarcities; 1 in 20 people may be displaced by a rising sea level; mortality may increase from vector‐borne diseases and from malnutrition linked to income losses. The later part of the Review is concerned with mitigation and adaptation strategies. It lays out an ambitious set of policies for transition to a low‐carbon economy that could stabilize greenhouse gas concentrations over the next several decades. By 2050, emissions would have to be 25 percent below today's and emissions per unit of GDP 75 percent below. In perhaps the most problematic part of the exercise the Review asserts that such cuts could be achieved at a cost of only around 1 percent of annual global GDP—implying that investment in mitigation should be strongly favored on straightforward economic grounds. (This figure, like others in the Review, is acknowledged to lie within a substantial envelope of uncertainty—here a range of ?1.0 percent to +3.5 percent of global GDP (p. 212), or, drawing on a wider range of models, ?4 percent to +15 percent (p. 241).) In the decades before the investment pays off, adverse consequences of the warming trends already underway must be dealt with by adaptation, such as through better disaster preparedness, lessening the vulnerability of infrastructure, and risk‐pooling measures. The excerpt is from pp. iii–iv and vi–xi. The full Stern Review (579 pages), the executive summary, and the commissioned background papers are available online at « http://www.hm‐treasury.gov.uk/independent_reviews/stern_review_economics_climate_change/sternreview_index.cfm ». A hard copy of the Review will be issued by Cambridge University Press.     

Immigration and environmental emissions: A U.S. county-level analysis

This paper investigates the immigration–environment association using U.S. county-level data, for a subset of counties (N = ~200), and a model inspired by the STIRPAT approach. The analysis makes use of U.S. census data for the year 2000 reflecting U.S.-born and foreign-born populations, combined with county-level data reflecting emissions of CO₂, NO₂, PM₁₀, and SO₂. With a focus on approximately 200 primarily urban counties for which complete data are available, and after controlling for income, employment in the utilities and manufacturing sectors, and coal consumption for SO₂ estimations, few statistically significant associations emerge between population composition and emissions. Counties with a relatively larger U.S.-born population have higher NO₂ and SO₂ emissions. On the other hand, counties with a relatively higher number or share of foreign-born residents have lower SO₂ emissions. Although limited to cross-sectional analyses, the results provide a foundation for future longitudinal research on this important and controversial topic.     

How do Recent Population Trends Matter to Climate Change?

Although integrated assessment models (IAM) of the Intergovernmental Panel on Climate Change (IPCC) consider population as one of the root causes of greenhouse gas emissions, how population dynamics affect climate change is still under debate. Population is rarely mentioned in policy debates on climate change. Studies in the past decade have added significantly to understanding the mechanisms and complexity of population and climate interactions. In addition to the growth of total population size, research shows that changes in population composition (i.e. age, urban–rural residence, and household structure) generate substantial effects on the climate system. Moreover, studies by the impact, vulnerability and adaptation (IAV) community also reveal that population dynamics are critical in the near term for building climate change resilience and within adaptation strategies. This paper explores how global population dynamics affect carbon emissions and climate systems, how recent demographic trends matter to worldwide efforts to adapt to climate change, and how population policies could make differences for climate change mitigation and adaptation.     

The precision of population projections studied by multiple prediction methods

A population projection is a prediction of a random vector variable X _T . which represents the size and age/sex distribution of the population in year T. The population is assumed to be closed and to develop according to fixed and known schedules of birth and death probabilities as a multitype branching process. The precision of the usual projection e _T (= EX _T) is studied by a family of prediction intervals of linear functions of the vector of deviations X _T — e _T , which has a preassigned probability level. This family is obtained by a multi-normal approximation and an argument similar to the one leading to Scheffé's method of multiple comparison. From the family of prediction intervals, an upper limit of the total absolute deviation Σ |X _iT ? e _it | is obtained, and the ratio of this limit to the projected total population is proposed as a measure of the relative precision of the projection. For a numerical study, Norwegian population data is used.     

The United Nations on World Population in 2300

The Population Division of the United Nations biennially issues detailed population estimates and projections covering the period 1950–2050. The most recent revision of these estimates and projections, the 2002 assessment, was released in February 2003. At irregular intervals, the Population Division also publishes long‐range projections. The most recent of these, covering the period up to 2150, was issued in 2000, based on the 1998 assessment. On 9 December 2003, the Population Division released the preliminary report on a new set of long‐range projections, dovetailing with the 2002 assessment, that extend over a much longer time span: up to 2300 ( http://www.un.org/esa/population/publications/longrange2/longrange2.htm ). Unlike previous long‐range projections, which, apart from China and In‐dia, were prepared for large regional groupings only, the new projections are elaborated separately for 192 countries. Given the enormous uncertainties of the character of demographic trends over such an extended period, the information content of these projections is somewhat elusive. However, they are expected to be used to provide the demographic input for long‐range models of global climate change. Long‐range population projections also serve to demonstrate the unsustainability of certain seemingly plausible assumptions as to the future course of particular demographic parameters. In the present case, for example, the high‐fertility projection, reflecting a sustained total fertility rate at the relatively modest level of 2.35, by 2300 would yield a population of some 32 billion in the countries now classified as less developed. Or, in a yet more extreme exercise 0/reductio ad absurdum, maintaining constant fertility at present rates would result in a population size of some 120 trillion in the countries now classified as least developed. Apart from the “high fertility” and “constant fertility” models just cited, the projections are calculated for three additional instructive variants: “low fertility,”“medium fertility,” and “zero growth.” Underlying each of the five variants is a single assumption on mortality change: expectation of life at birth creeping up, country‐by‐country, to a 2300 level ranging between 88 and 106 years. International migration is set at zero throughout the period 2050‐2300 in each variant. Thus the projections are unabashedly stylized and surprise‐free, providing a simple demonstration of the consequences, in terms of population size and age structure, of clearly stated assumptions on the future course of demographic variables. Reproduced below is the Executive Summary of the preliminary report on the UN long‐range projections presented to a UN technical working group on long‐range projections at its December 2003 meeting in New York and slightly revised afterward. A full final report on this topic by the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat will be published later in 2004.     

Population, climate, and electricity use in the Arctic integrated analysis of Alaska community data

Towns and villages of Arctic Alaska experience substantial year-to-year variations in weather, overlaid on longer-term warming trends. Community populations often are changing as well, reflecting highly variable net migration, overlaid on longer-term trends of natural increase. Both environmental and population change affect Arctic communities?? energy needs. Energy needs in the Arctic tend to be high and expensive, posing challenges to communities?? long-term viability. In this paper, we analyze relationships between weather, population, and one important measured component of energy??community-level electricity consumption. Electricity for the most part is generated locally from diesel fuel, which has a local environmental footprint as well. Taking a new approach to the integrated analysis of climate and human-dimensions data, we apply mixed-effects modeling to time series of electricity, weather, population, and price indicators across 42 Alaska towns and villages. Population dominates annual variations in electricity use, showing both general and community-specific effects that are strongest in the regional centers. Weather also affects electricity use, but for different reasons than it does in more urban areas to the south. Given population stability, a warming climate should lead to lower electricity demand. Population growth can override climate effects, however. Net of population, weather, and price, there has been an upward trend in per capita electricity use.     

The future of world population

Analysis of future population trends reveals a regional pattern of continued growth, dependent upon basic assumptions about demographic factors and the priority given to human rights, socioeconomic development, and global interdependence. Developing countries will account for 85-87% of world population growth, and the most rapid increase will occur in Africa. The optimum size of population remains debatable. Ecologist argue for a reduction to 1-2 billion people in order to be in balance with nature and maintain a high quality of life. A rapid, but plausible, fertility decline would result in a population of 10 billion by 2070. The lowest feasible UN projection is 8 billion. A 1-2 billion world population would not be feasible without drastic mortality increases and fertility declines. Population control is a highly charged and complex issue; feminists are not about to place responsibility for environmental degradation on women's excess fertility. The spirit of the UN Universal Declaration of Human Rights is that women have the right to determine family size with personal integrity and freedom rather than suffer coercion for the rights of society. Family planning is a necessary ingredient for achieving the goal of desired family size. The quality of life may be undermined by upholding human rights, without recognition of the context of socioeconomic development and global interdependencies. Global economic conditions, political crises, and environmental degradation can undermine even the best national development efforts. The most difficult task ahead is addressing priorities and forming a consensus. Human rights, socioeconomic conditions, and global interdependencies must be satisfied in a mutually beneficial way. When national and global goals conflict, a compromise must be reached. There are many unknowns. The challenge is to "identify a set of policies that will stabilize world climatic conditions, promote economic development, enhance the quality of life, and respect human rights." Investment in human capital, such as education and health, will help women to avoid unwanted pregnancies. Improving the status of women is key to socioeconomic development, human rights, and global interdependencies.     

Energy, population and the environment: exploring Canada’s record on CO2 emissions and energy use relative to other OECD countries

Across the OECD, Canada??s record on CO₂ emissions is particularly poor, with overall emissions up 32% over the 1990?C2007 period. The current paper seeks to better understand this situation by making systematic comparisons of Canada with other OECD countries. For Canada overall, the rapid increase in emissions over the 1990?C2007 period can be explained by several factors, including major population growth, increased affluence (although to a lesser extent than elsewhere in the OECD), a continued dependence on fossil fuels, while continuing to increase its overall demand for energy. While the energy intensity of Canada??s economy has declined somewhat over recent years, it actually lagged behind most OECD countries on this front and remains one of the most energy intense economies in the world (2nd highest in the OECD on our indicator of energy intensity). While there are many factors responsible for this, Canada??s particularly energy-intensive industrial structure is certainly relevant, as is the importance of its primary sector relative to most developed nations.     

The Census Bureau on Prospects for US Population Growth in the Twenty‐First Century

The U.S. Census Bureau periodically releases projections of the US resident population, detailed by age, sex, race, and Hispanic origin. The most recent of these, issued 13 January 2000, for the first time extend to the year 2100 and also include information on the foreign‐bom population. (Earlier projections were carried up to 2080.) The extensive tabulations presenting the new set, and detailed explanation of the methodology and the assumptions underlying the projections, are accessible at the Census Bureau's web site: http://www.census.gov . A brief summary of some of the main results of these projections is reproduced below from United States Department of Commerce News, Washington, DC 20230. (The Census Bureau is an agency of the Department of Commerce.) Uncertainties as to future trends in fertility, mortality, and net migration over a period of some 100 years are very great, as is illustrated by the massive difference in the projected size of the population for 2100 in the three variants produced. The “middle” projected population figure of 571 million (which represents a growth of some 109 percent over its current level) is bracketed by “lowest” and “highest” alternative projections of 283 million and 1.18 billion, respectively. With somewhat lesser force, the point also applies to the 50‐year time span considered in the well‐known country‐by‐country projections of the United Nations. These projections are also detailed in three variants: low, middle, and high. The UN projections (last revised in 1998) envisage less rapid growth in the United States during the first part of the twenty‐first century than do the Census Bureau's. The projected population figures for 2050 in the three variants (low, middle, and high) are as follows (in millions):

我国人口-经济-二氧化碳排放的关联研究

通过全国1995～2008年各省区二氧化碳排放和人口发展状况对比发现,人口与二氧化碳排放之间并不呈现简单的正相关关系。本文引入经济系统对人口与二氧化碳排放之间的关系进行关联分析。研究发现,在短时期内,人口增长对二氧化碳排放的影响不可忽视,但从长远来看,经济增长对二氧化碳排放影响更为重要。值得注意的是,虽然人口和经济增长是二氧化碳排放变化的原因,但当滞后期延长,人口和经济系统之间将互为因果,使得人口和二氧化碳排放的关系将更为复杂。     

Causal Relationships among Population and Carbon Dioxide Emissions

The carbon dioxide emissions of the provinces would be calculated from 1995 to 2008.And we compare the provinces’ carbon dioxide emissions and population development.We found that the relationship between population and carbon dioxide emissions are not a simple correlation.In order to probe the relation,we introduce the economic variable into the research,take advantage the cointegration analysis and Granger causality test.The paper found that the population and economic growth is the main reason of carbon dioxide emission change.In short run the population growth would impact the carbon dioxide emissions,and increase in carbon dioxide emissions cannot be simply attributed to overpopulation,economic growth impact on carbon dioxide emissions more strongly.     

Global Warming: New Scenarios from the Intergovernmental Panel on Climate Change

The Intergovernmental Panel on Climate Change (IPCC) was set up in 1988 by the World Meteorological Organization and the United Nations Environment Programme to review the state of knowledge about human‐induced climate change and assess possible responses. Most of its activities are conducted by three working groups, concerned respectively with scientific aspects of the climate system, with the vulnerability of human and natural systems to climate change, and with options for mitigating that change. The major IPCC reports have been highly detailed statements of scientific consensus on changes in the climate system, issued at roughly five‐year intervals. These reflect the input of some hundreds of scientists, with drafts scrutinized by expert reviewers, revised to attain consensus, and eventually approved (or “accepted”) by the full Panel. The first such assessment, published in 1990, was influential in formulating the Framework Convention on Climate Change adopted at the 1992 Rio conference. The second assessment report (SAR), Climate Change 1995, produced the widely cited estimate that global warming would raise average temperatures by 1°–3.5°C by 2100, with a “best estimate” of 2°C, and produce a sea‐level rise of 0.13 – 0.94 meters. That report took the further step of explicitly linking the warming to anthropogenic (human‐caused) emissions of greenhouse gases. Its cautious conclusion: “The balance of evidence suggests a discernible human influence on global climate.” Climate Change 2001: The Scientific Basis is Working Group I's contribution to the third IPCC assessment. The document was finalized at the Group's meeting in Shanghai in January 2001. A brief (18‐page) “Summary for Policymakers” was also released at this meeting, distilling the findings of the full report and putting them in more accessible language. Two sections of this summary document, presenting the Group's projections of atmospheric temperature trends and sea‐level rises, are reproduced below. The procedure followed was to assemble hypothetical alternative combinations of future greenhouse gas emissions in the form of emission scenarios, which were fed into large‐scale climate models to produce estimates of future temperature and sea‐level trends. For the third assessment report the scenarios used were set out in the IPCC Working Group Ill's Special Report on Emission Scenarios (March 2000), and are referred to below as the “SRES scenarios.” There are 35 of them in all. They fall into six groups, detailed in the text box, from each of which an illustrative case is plotted in the charts. (The shaded areas in the charts are envelopes spanning the 35 scenarios. Some additional details shown in the original charts have been omitted here for clarity.) The SAR scenarios are referred to as IS92. The major difference from the second assessment is in the projected temperature increase, which is now put at 1.4°–5.8°C (or in Fahrenheit degrees, 2.5°–10.4°). The projected sea‐level rise is slightly smaller, at 0.09 – 0.88 meters. There is also a strengthening of the statement on anthropogenic causes, which now reads: “There is new and stronger evidence that most of the [atmospheric] warming observed over the last 50 years is attributable to human activities.” The report notes that even with stabilization of greenhouse gas emissions, there may be continuing climate effects beyond the twenty‐first century. One such effect is the “weakening of ocean thermohaline circulation “—the ocean currents that, for example, transport heat into high northern‐hemisphere latitudes and moderate the coastal climates of those regions. The summary report is available online at the IPCC's website, www.ipcc.ch . The complete third assessment report, covering also the conclusions of Working Groups II and III (particularly on the social and economic costs of forecast climate change), will be released shortly.     

A worldwide view of population trends

The UN Population Commission held its 20th session in New York from 29 January to 9 February, with an agenda that included reviews of UN action to implement recommendations of the 1974 World Population Conference; of progress in population work by the UN Population Division; and of the medium-term plan, 1980-1983. Of a total of 29 countries and 22 organizations participating, 5 countries were Asian--India, Indonesia, Japan, the Philippines, and Thailand. The report on monitoring of trends and policies was the most detailed examination of the global demographic situation yet available, and revealed the following facts: 1) 80% of the population of the developing countries are in countries which the governments have considered that a slower rate of population growth would be desirable; 2) among developed countries, nearly all governments preferred their rate of population growth to remain as high as or become higher than at present; 3) among the developing countries, 6 of the 8 nations having a population greater than 50 million wished to reduce their rate of growth; 4) 80% of all countries considered the rate of population growth the be of basic importance for development; and 5) with respect to mortality, about 75% of all governments of developing countries considered the prevailing level to be unsatisfactory; while among developed countries the same proportion considered the prevailing level to be acceptable. As a result of its deliberations on the report, the Population Commission endorsed the Population Information Network concept of a decentralized network for the coordination of regional, national, and nongovernmental population information activities.     

Operationalising the Concept of Motility: A Qualitative Study

Abstract

This article aims to be a contribution towards an understanding of the interplays between subjective, situated and normative justifications for traveling and the imaginary of class and global warming in Brazil. Taking as its empirical reference the largest favela in Rio de Janeiro, it focuses on how people who are having the opportunity to travel by plane for the first time accommodate three interrelated issues: their willingness to experience an energy intensive way of travelling, their affective and material realities, and their awareness about the changing of the world’s climate. The article concludes with some reflections on how to reintegrate global knowing with local meaning around travel and climate change.     

Prospects for fertility reduction and projections for future population growth in Kenya

In 1979 Kenya's annual rate of natural population growth was 3.8%. Data from the1989 Kenya Demographic and Health Survey indicate that significant decreases in fertility levels were experienced during the 1980s. Factors associated with conditions supportive of high fertility in Kenya are discussed, and progress toward attaining significant fertility reduction thresholds during the 1980s is assessed. Findings from recent fertility surveys are presented, and 1969–1989 national level family planning data are evaluated. Four population projections for 1985–2025 are presented and analyzed. One projection is based on official government growth targets; two are based on estimates provided by the United Nations and the Population Reference Bureau, and a fourth projection is based on the assumption that Kenya will attain an annual natural population growth rate of less than 1% by the year 2025. Each projection assumes that fertility declines will be experienced. Kenya's prospects for reducing the annual population growth rate to 1% within the next sixty years and a cost-sharing development policy are addressed briefly in the concluding section. Recent data suggest that Kenya will probably not complete the demographic transition before the year 2050, but Kenya should continue to move through the transition stage.     

Estimating Traffic Emissions Using Demographic and Socio-Economic Variables in 18 Chilean Urban Areas

A macro-scale methodology for vehicle emissions estimation is described. The methodology is based on both correlations between activity level and PM, CO, THC and NO _x vehicle emissions and relationships between demographic and socio-economic variables and transportation activity level. First, pollutant emissions were correlated with transportation activity, expressed as vehicle-km/year, using existing data collected from mobile sources emission inventories in nine urban cities of Chile. Second, demographic and socio-economic variables were pre-selected from those that could intuitively be correlated with vehicle activity level and considering the data availability. Using the individual R ² correlation coefficient as variable selection criterion, population, the number of vehicles, fuel consumption, gross domestic product, average family incomes and road kilometers were finally chosen. A different set of explicative variables was considered for different vehicle categories, based on the selection criterion above mentioned. Then, correlation functions between these variables and transport activity were obtained by non-linear Gauss–Newton least square method. This methodology was applied to eighteen provinces of the country obtaining total annual emission for mobile sources, divided into six main vehicles categories.