Perspectives on International Trends and Dynamics in Population and Consumption

There are increasing concerns that global environmental limits may soon be met as a result of increasing numbers of people coupled with increasing consumption of resources. However, the current level and rates of growth in both consumption and population vary systematically among countries grouped according to income levels. Many high income countries have population growth rates at close to replacement levels, but their per capita consumption is consistently several times higher than low income countries. Low income countries need to grow out of poverty and have high population growth rates. Using current population structures for India and the USA in an age-structured demographic model, and simple projections of annual reductions in fertility or consumption per capita over the next 50 years, we show that while reductions in both consumption and fertility are necessary to stabilize impacts, there are short term gains from consumption reductions in high income countries such as the USA, and long term gains from early fertility reductions in growing economies such as India.     

Growth in global materials use, GDP and population during the 20th century

The growing industrial metabolism is a major driver of global environmental change. We present an assessment of the global use of materials since the beginning of the 20th century based on the conceptual and methodological principles of material flow accounting (MFA). On the grounds of published statistical data, data compilations and estimation procedures for material flows not covered by international statistical sources, we compiled a quantitative estimate of annual global extraction of biomass, fossil energy carriers, metal ores, industrial minerals and construction minerals for the period 1900 to 2005. This period covers important phases of global industrialisation and economic growth. The paper analyses the observed changes in the overall size and composition of global material flows in relation to the global economy, population growth and primary energy consumption. We show that during the last century, global materials use increased 8-fold. Humanity currently uses almost 60 billion tons (Gt) of materials per year. In particular, the period after WWII was characterized by rapid physical growth, driven by both population and economic growth. Within this period there was a shift from the dominance of renewable biomass towards mineral materials. Materials use increased at a slower pace than the global economy, but faster than world population. As a consequence, material intensity (i.e. the amount of materials required per unit of GDP) declined, while materials use per capita doubled from 4.6 to 10.3 t/cap/yr. The main material groups show different trajectories. While biomass use hardly keeps up with population growth, the mineral fractions grow at a rapid pace. We show that increases in material productivity are mostly due to the slow growth of biomass use, while they are much less pronounced for the mineral fractions. So far there is no evidence that growth of global materials use is slowing down or might eventually decline and our results indicate that an increase in material productivity is a general feature of economic development.     

中国养活自己能力的长期预测:技术和政策分析

中国拥有世界五分之一强的人口 ,收入又在迅速增长。因此 ,国际上很自然地会考虑或推测她在今后的几十年是否有能力养活自己。中国的人口预计将从 2 0 0 0年的 1 2 8亿增长到 2 0 2 0年的 1 4 6亿 ,和 2 0 3 0年的 1 4 9亿。与此同时 ,人均收入的增长将导致对家畜和鱼类产品更大的需求 ,因而对饲料的需求也将有很大的增长     

GLOBAL POPULATION GROWTH,TECHNOLOGY, AND MALTHUSIAN CONSTRAINTS: A QUANTITATIVE GROWTH THEORETIC PERSPECTIVE

We structurally estimate a two‐sector Schumpeterian growth model with endogenous population and finite land reserves to study the long‐run evolution of global population, technological progress, and the demand for food. The estimated model closely replicates trajectories for world population, GDP, sectoral productivity growth, and crop land area from 1960 to 2010. Projections from 2010 onward show a slowdown of technological progress, and, because it is a key determinant of fertility costs, significant population growth. By 2100, global population reaches 12.4 billion and agricultural production doubles, but the land constraint does not bind because of capital investment and technological progress.     

Bearing many children,morality, and ecology

The relationship between high fertility and population growth on the one hand, and environmental quality on the other, is explored. The author suggests that efforts to decrease the size of the global population will cause more problems than they solve. In contrast, he states that a global population of about 10 to 12 billion by the year 2050 is probably inevitable. Population should level off at that number and be capable of sustaining itself on this planet, providing the political problems the world faces can be resolved by then.     

Demographic and Economic Pressure on Emigration out of Africa*

Two of the main forces driving European emigration in the late nineteenth century were real wage gaps between sending and receiving regions and demographic booms in the low‐wage sending regions. Our new estimates of net migration for the countries of sub‐Saharan Africa show that exactly the same forces driving African across‐border migration are at work today. The results suggest that rapid growth in the cohort of potential young emigrants, population pressure on the resource base, and slow economic growth are likely to intensify the pressure for migration out of Africa and into high‐wage OECD countries over the next two decades.     

On the forecasting of the challenging world future scenarios

Logistic and power law methodologies for both retrospective and prospective analyses of extended time series describing evolutionary growth processes, in environments with finite resources, are confronted. While power laws may eventually apply only to the early stages of said growth process, the Allee logistic model seems applicable over the entire span of a long range process. On applying the Allee logistic model to both the world population and the world gross domestic product time series, from 1 to 2008 AD, a projection was obtained that along the next few decades the world should experience a new economic boom phase with the world GDP peaking around the year 2020 and proceeding from then on towards a saturation value of about 142 trillion international dollars, while the world population should reach 8.9 billion people by 2050. These results were then used to forecast the behavior of the supply and consumption of energy and food, two of the main commodities that drive the world system. Our findings suggest that unless the currently prevailing focus on economic growth is changed into that of sustainable prosperity, human society may run into a period of serious economical and social struggles with unpredictable political consequences.     

World population growth and the role of annual energy use per capita

In the context of ongoing world population growth, no permanent growth in materials consumption can be sustained into the future. A sustainable future requires that the world's population stabilize. The author considers the possible coupling of the annual energy use per capita and the population growth rate for each region, and the consequences of such a connection if the world's population is to stabilize. Energy is used as a factor because it is a proactive agent in facilitating increases in the standard of living and changes in the social conditions thought to influence the fertility rate. Historical trends and near-term projections for energy use and population growth rate are used to indicate a possible future path for developing regions. Improvements in the efficiency of energy use and modest cultural changes are used in an example projection of coupled energy use and population growth. For each decade, the incremental increase in annual commercial energy use per capita and a corresponding decrease in population growth rate are chosen to continue the historical trends for developing regions of the world. This approach results in population changes which closely follow the projections of the World Bank for the period up to 2150. World energy use is projected to increase from about 9000 million tons of oil equivalent (Mtoe) today to 15,000-21,000 Mtoe/a by the time the world's population has risen from 6 billion to about 12 billion in the 22nd century. The energy demands of each developing region are compared with potential, indigenous energy sources to determine whether each developing region may be able to cope with its increased energy demand without massive energy imports. The availability of readily moveable, cheap fuels will help the developing world make the transition to a more stable population with a decent standard of living.     

Fertility and climate change*

A quarter of the total increase in emissions is attributable to the growth of emissions per capita, whereas three-quarters are due to population growth. This evidence notwithstanding, demography in climate–economy models typically follows exogenous trends. We develop a climate–economy integrated model with endogenous fertility through a quality–quantity trade-off. The decentralization of the social optimum requires two complementary instruments: a carbon pricing policy and family planning interventions. Global population increases and reaches a peak, depending on the scenario, between 11.6 billion in the social optimum and 14.6 billion if only carbon prices are implemented. Fertility costs (i.e., the net present value of the climate-related costs per child) are in 2020 estimated to be about 22,000 euros in the “social optimum” scenario, and about 88,000 euros in the “second-best with fertility taxes” scenario. Carbon pricing tends to have a rebound effect as it increases population growth leading to higher future emissions. Our results highlight the effects of fertility choices and global population on climate change, quantifying the cost of neglecting the interaction.     

Exploring past and future changes in the ecological footprint for world regions

The Ecological Footprint (EF) has received considerable attention as a useful indicator in the context of sustainable development. So far, it has mostly been applied as a static indicator. Here, we have derived a set of long-term EF scenarios for 17 world regions using the IMAGE 2.2 implementation of the IPCCs SRES scenarios. The scenarios are used to discuss potential trends in EFs in different world regions but also to analyse underlying trends driving changes in the EF. The baseline scenarios show the EF for real land use only (not accounting for CO₂) to increase further in the next few decades in most world regions, being driven by population growth, changes in human diets towards more land-intensive products and overall increases in consumption levels. Future crop yield improvements and technology development will partly offset these trends, resulting in decreasing per capita EFs, but increasing total EFs. In the longer term, EF development may strongly diverge on the basis of assumptions made in the different baseline scenarios (from 5.4 Gha at present to 6.0–8.2 Gha in 2050 depending on the scenario). The aggregated EF following the definition of Wackernagel et al. (Proc. Natl. Acad. Sci. 99 (2002) 9266–9271) (including virtual land for CO₂) increases more strongly, from 12.6 to 20–31 Gha depending on the different scenarios. An alternative scenario was developed to explore whether optimistic assumptions for changes in consumption and production patterns could limit the increase of the global EF, which limited EF increase to 15 Gha in 2050. This scenario still allowed for population growth and strong economic development in low-income regions.     

Preparing Africa for the twenty-first century: Lessons from constitutional economics

In the 1960s, when most African countries gained independence, they had an opportunity to select new political and economic institutions to promote growth and development. After more than three decades of political autonomy, it now appears that the opportunity made possible by decolonization was wasted and never fully utilized to promote sustainable development in the continent. As a result, after more than thirty years of independence, most of Africa remains poor and highly deprived. Political economy in the continent is characterized by opportunism, promoted by political coalitions whose primary objective is to subvert the rules to generate benefits for themselves. The end of the Cold War and the subsequent cessation of superpower rivalry, in addition to the demise of apartheid in South Africa, has provided policy makers in Africa another opportunity to choose new institutions to lead Africans into the twenty-first century. Public choice and constitutional economics provide guidelines that can be utilized to develop efficient and self-enforcing institutions to enhance development and effect significant increases in social welfare in Africa in the next century.     

Is Local Food More Environmentally Friendly? The GHG Emissions Impacts of Consuming Imported versus Domestically Produced Food

With the increased interest in the ‘carbon footprint’ of global economic activities, civil society, governments and the private sector are calling into question the wisdom of transporting food products across continents instead of consuming locally produced food. While the proposition that local consumption will reduce one’s carbon footprint may seem obvious at first glance, this conclusion is not at all clear when one considers that the economic emissions intensity of food production varies widely across regions. In this paper we concentrate on the tradeoff between production and transport emissions reductions by testing the following hypothesis: Substitution of domestic for imported food will reduce the direct and indirect Greenhouse Gas (GHG) emissions associated with consumption. We focus on ruminant livestock since it has the highest emissions intensity across food sectors, but we also consider other food products as well, and alternately perturb the mix of domestic and imported food products by a marginal (equal) amount. We then compare the emissions associated with each of these consumption changes in order to compute a marginal emissions intensity of local food consumption, by country and product. The variations in regional ruminant emissions intensities have profound implications for the food miles debate. While shifting consumption patterns in wealthy countries from imported to domestic livestock products reduces GHG emissions associated with international trade and transport activity, we find that these transport emissions reductions are swamped by changes in global emissions due to differences in GHG emissions intensities of production. Therefore, diverting consumption to local goods only reduces global emissions when undertaken in regions with relatively low emissions intensities. For non-ruminant products, the story is more nuanced. Transport costs are more important in the case of dairy products and vegetable oils. Overall, domestic emissions intensities are the dominant part of the food miles story in about 90 % of the country/commodity cases examined here.     

On the relationship between population change and sustainable development

This paper investigates the relationship between population growth and economic growth, through the study of fertility choices and their effects on natural resources. It aims at analyzing the interactions between endogenous fertility choices and the environment and their link to the sustainable matter. We analyze a growth model driven by natural resources and without production, where agents have jointly to determine consumption and fertility, taking into account the effects of their decisions on the dynamics of natural resources. We adopt the most optimistic view on natural capital (it generates endogenous growth) and the weakest notion of sustainable paths (all variables are positive): in such a framework we expect that sustainable paths exist. We instead show that this is not always true. In fact, even if renewal capacity of natural resources is unbounded, not always can a sustainable path be found: this depends on the difference between the stationary fertility rate and the mortality rate. If the stationary fertility is lower than the mortality rate, a sustainable path will not be found, and in such a case public intervention is necessary in order to address the economy along a sustainable path. This can simply be done through policies affecting public attention to environmental protection or the intensity of the dilution effect.     

The Helios strategy: An heretical view of the potential role of solar energy in the future of a small planet

Over the next hundred years there must be a worldwide transition from reliance on fossil fuels to the use of some combination of long-term and abundant primary sources for the production of heat, electricity, and synthetic fuels. The rate at which such options can be developed and employed, as well as the maximum rate at which they can provide energy at a sustained rate, will place important constraints on the rate and limits to growth of other human activities. It is generally argued that only the fission option, in the form of the fast-breeder and high-temperature reactors, can provide the energy required for a livable world, particularly if this means a world of 10 billion people living at the present energy level of Western Europe. However, a careful examination indicates that the use of solar energy, through a menu of technological options, can provide the needs of a world at this scale of energy use, and that this can be accomplished within the constraints of land availability and requirements for energy, materials, and labor. No scientific breakthroughs are required, although a number of these would be helpful, but very substantial engineering advances are required, and the transition of such a world-wide system would take no less than a century. However, the feasibility of such large-scale use of solar energy will substantially alter those aspects of the “limits to growth” discussions in which future growth strategies are constrained by available and acceptable energy alternatives. This paper outlines a global solar-energy system considered feasible for more than 10 billion people living at 5 kW per capita.     

Out of Africa? Using the Past to Project African Emigration Pressure in the Future

The paper uses analysis of the mass emigration from poor Europe in the late nineteenth century to project the future mass emigration potential from Africa, especially to the economically more mature Mediterranean economies. The economic and demographic fundamentals driving both experiences are likely to be the same, but their magnitudes are likely to be far bigger in the African case over the next few decades. Efforts to restrict the migration and to seal porous borders may be partially successful; but, if so, they are certain to create unpleasant side–effects. European restrictions will create a greater share of illegals and thus greater absorption problems in recipient nations: European restrictions will create more poverty in African sending regions. And European restrictions will create considerable diplomatic problems between the two regions.     

Assessing the impact of AIDS on the growth path of the Malawian economy

More than 1% of people of sub-Saharan Africa aged 15-49 years are infected with HIV, with over half likely to develop AIDS in the next decade. As rates of HIV infection continue to climb, there will be staggering financial consequences to bear in the years ahead in terms of high medical treatment costs and crippled macroeconomies. The authors employ a modified Solow growth model to simulate the impact of the AIDS epidemic on output capacity and other key macroeconomic aggregates in Malawi. They compare a counterfactual no-AIDS scenario to medium and extreme AIDS projections and find that average real GDP growth over the 1985-2010 period will be 0.2-0.3 percentage points lower in the medium case and 1.2-1.5% lower in the extreme case relative to the no-AIDS case. The size of the economy by 2010 will therefore be reduced from a real GDP of 5.03 billion (constant 1985) Kwacha without AIDS to 4.81-4.77 and 3.80-3.46 billion Kwacha in the medium and extreme scenarios, respectively.     

Rapid industrialization and market for energy and minerals: China in the East Asian context

The mainland of China’s rapid pace of industrialization and trade expansion have led many to ask whether its ever-increasing demand for resources can be met without disruption to economic stability and growth in the country and the world as a whole. The article examines the experience of growth in resource demand and the associated pressure on global markets from Japan, Taiwan Province of China and Korea during their periods of sustained, rapid economic growth for periods in the second half of the twentieth century. It seeks to draw lessons for the twenty-first century. The article points out that because of its size the mainland of China may cause the resources boom, associated with the later decades of its period of sustained rapid growth, to raise the prices of resource-intensive products by a large amount, not for a few years, but for several decades. This will have important implications for economic development and the distribution of incomes within and between all countries, and on power relations between states in the Asia-Pacific and throughout the global community.     

COVID-19 and Long-Term Economic Growth

This article investigates the impact of the COVID-19 pandemic on the long-term economic growth of South Africa. We embed an epidemiological model in a modified Solow–Swan model and explore various channels such as morbidity, mortality, unemployment, loss of school days and capital accumulation. We demonstrate that COVID-19 will lower the average annual growth rate of GDP per capita of South Africa by 0.07 percentage points in the next four decades, a 25 per cent decline relative to the no-COVID benchmark. We show that human capital losses due to school closures account for more than half of the economic slowdown.     

Global patterns of socioeconomic biomass flows in the year 2000: A comprehensive assessment of supply, consumption and constraints

Human use of biomass has become a major component of the global biogeochemical cycles of carbon and nitrogen. The use of land for biomass production (e.g. cropland) is among the most important pressures on biodiversity. At the same time, biomass is indispensable for humans as food, animal feed, raw material and energy source. In order to support research into these complex issues, we here present a comprehensive assessment of global socioeconomic biomass harvest, use and trade for the year 2000. We developed country-level livestock balances and a consistent set of factors to estimate flows of used biomass not covered by international statistics (e.g. grazed biomass, crop residues) and indirect flows (i.e. biomass destroyed during harvest but not used). We found that current global terrestrial biomass appropriation amounted to 18.7 billion tonnes dry matter per year (Pg/yr) or 16% of global terrestrial NPP of which 6.6 Pg/yr were indirect flows. Only 12% of the economically used plant biomass (12.1 Pg/yr) directly served as human food, while 58% were used as feed for livestock, 20% as raw material and 10% as fuelwood. There are considerable regional variations in biomass supply and use. Distinguishing 11 world regions, we found that extraction of used biomass ranged from 0.3 to 2.8 t/ha/yr, per-capita values varied between 1.2 and 11.7 t/cap/yr (dry matter). Aggregate global biomass trade amounted to 7.5% of all extracted biomass. An analysis of these regional patterns revealed that the level of biomass use per capita is determined by historically evolved patterns of land use and population density rather than by affluence or economic development status. Regions with low population density have the highest level of per-capita biomass use, high-density regions the lowest. Livestock, consuming 30-75% of all harvested biomass, is another important factor explaining regional variations in biomass use. Global biomass demand is expected to grow during the next decades; the article discusses some options and possible limitations related to such a scenario.     

Challenging the human crisis: “The trilemma”

The great increase in world population in the coming century will result in a human crisis of worldwide proportions. A new concept for describing and proposing solutions to this crisis, called the Trilemma, is described by the authors. To feed large and growing populations, humankind is now being forced to make the difficult choice between producing sufficient food for the world population and preserving the environment, or generating economic growth, requiring the consumption of energy and natural resources. These difficult choices present the Trilemma, a new concept that is composed of three dimensions: economic growth, resources such as energy and food, and the environment. None of these three dimensions can be optimized individually as they are mutually interdependent.This paper describes a possible world energy condition in the 21st century. Three scenarios of this energy consumption are presented and compared with the possible energy supply at that time. This supply is estimated from the extrapolation of the renewable energy development of the past and the possible fossil fuel supply. The comparison of the energy supply and the energy consumption indicates that the annual rate of economic growth in the developed region would be only 1% if the gross national product (GNP) per capita of the developing region increases gradually from 1/26 of the GNP of the developed regions in 1990, to 1/10 in 2020, and finally to 1/3 in 2100.Another possibility is that if the GNP per capita of the developing region remains 1/26 of the GNP of the developed regions between 1990 and 2100, the economic growth rate in the developed region could be as large as 3%. In the latter case, an energy shortage would develop in the middle of the 21st century, even if the fast breeder reactor were fully operational by the year 2030. Energy technological developments in Japan are also described as a part of the possible countermeasures against the Trilemma.