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1.
The world population is expected to rise to 9.7 billion by 2050 and to ~11 billion by 2100, and securing its healthy nutrition is a key concern. As global fertile land is limited, the question arises whether growth in food consumption associated with increased affluence surmounts increases in land-use efficiency (measured as food supply per cropland area) associated with technological progress. Furthermore, substantial inequalities prevail in the global food system: While overly rich diets represent a serious health issue for many of the world’s most affluent inhabitants and constitute a critical climate-change driver, undernourishment and hunger still threaten a considerable fraction of the world population, mostly in low-income countries. We here analyze trajectories in cropland demand and their main basic drivers food consumption (measured by a food index reflecting the share of animal products in diets) and land-use efficiency, for 123 countries (clustered in four income groups, covering 94% of the world population). We cover the period 1990–2013 and assess if these trajectories are associated with changes in inequality between countries. We find that while all groups of countries converged towards the high level of the per-capita food consumption of high-income countries, differences between income groups remained pronounced. Overall, cropland demand per capita declined over the entire period in all regions except low income countries, resulting in a tendency towards global convergence. However, the trend slowed in the last years. In contrast, land-use efficiency increased in all income groups with a similar trend, hence international inequalites in land-use efficiency remained almost unaltered. Because population and food requirements per capita are expected to grow in all income groups except the richest ones, failure to improve land efficiency sufficiently could lead to a less unequal but at the same time less ecologically sustainable world. Avoiding such outcomes may be possible by reducing the consumption of animal products in the richer countries and raising land-use efficiency in the poorer countries.  相似文献   

2.
Affluence drives the global displacement of land use   总被引:2,自引:0,他引:2  
Increasing affluence is often postulated as a main driver for the human footprint on biologically productive areas, identified among the main causes of biodiversity loss, but causal relationships are obscured by international trade. Here, we trace the use of land and ocean area through international supply chains to final consumption, modeling agricultural, food, and forestry products on a high level of resolution while also including the land requirements of manufactured goods and services. In 2004, high-income countries required more biologically productive land per capita than low-income countries, but this connection could only be identified when land used to produce internationally traded products was taken into account, because higher-income countries tend to displace a larger fraction of land use. The equivalent land and ocean area footprint of nations increased by a third for each doubling of income, with all variables analyzed on a per capita basis. This increase came largely from imports, which increased proportionally to income. Export depended mostly on the capacity of countries to produce useful biomass, the biocapacity. Our analysis clearly shows that countries with a high biocapacity per capita tend to spare more land for nature. Biocapacity per capita can be increased through more intensive production or by reducing population density. The net displacement of land use from high-income to low-income countries amounted to 6% of the global land demand, even though high-income countries had more land available per capita than low-income countries. In particular, Europe and Japan placed high pressure on ecosystems in lower-income countries.  相似文献   

3.
As global temperatures go up and incomes rise, air conditioner sales are poised to increase dramatically. Recent studies explore the potential economic and environmental impacts of this growth, but relatively little attention has been paid to the implications for inequality. In this paper we use household-level microdata from 16 countries to characterize empirically the relationship between climate, income, and residential air conditioning. We show that both current and future air conditioner usage is concentrated among high-income households. Not only do richer countries have much more air conditioning than poorer countries, but within countries adoption is highly concentrated among high-income households. The pattern of adoption is particularly stark in relatively low-income countries such as Pakistan, where we show that the vast majority of adoption between now and 2050 will be concentrated among the upper income tercile. We use our model to forecast future adoption, show how patterns vary across countries and income levels, and discuss what these patterns mean for health, productivity, and educational inequality.  相似文献   

4.
The foundations of modern society are based on metals, yet their production is currently placing considerable strain on the Earth’s carrying capacity. Here, we develop a century-long scenario for six major metals (iron, aluminum, copper, zinc, lead, and nickel) harmonized with climate goals, with the goal of establishing science-based targets. We show that for the metal sector to contribute proportionally to emission reductions targets of the industrial sector, global in-use metal stocks need to converge from the current level of around 4 t/capita to about 7 t/capita. This will require today’s high-income countries to contract their per capita stock from current levels of about 12 t/capita to make room for growth in countries that are presently classified as middle- and low-income countries. In such a contraction and convergence scenario, primary production of all six metals will peak by 2030, and secondary production will surpass primary production by at least 2050. Consequently, cumulative ore requirements over the 21st century will remain below currently identified resources, implying that natural ore extraction will be limited by emissions budgets before existing resources can be depleted. Importantly, realizing such system changes will require urgent and concerted international efforts involving all countries, but specific responsibilities will vary according to income level. Namely, wealthy countries will need to use existing metal stocks more intensively and for longer periods to reduce stock replacement demand, while poor countries will need to develop long-lasting and material-efficient infrastructure to curtail stock expansion demand in the first half of the 21st century.  相似文献   

5.
Dramatic increases in liquid biofuel production have led to concerns about associated impacts on food prices, with many modeling studies showing significant biofuel-related price inflation. In turn, by changing patterns of food demand, biofuel production may indirectly influence greenhouse gas emissions. We estimated changes to dietary energy (calorie) demand and greenhouse gas emissions embodied in average diets under different biofuel-related food-price scenarios for Brazil, China and the United States, using food-price projections and food-price elasticities. Average energy demand decreased in all countries, from about 40 kcal per person per day in Brazil under a moderate price inflation scenario – a reduction of 1% relative to the (2009) reference scenario – to nearly 300 per day in the United States with high price inflation – almost 8% of reference levels. However, emissions per calorie increased slightly in all three countries. In terms of total greenhouse gas emissions, the results are suggestive of overall reductions only in the United States, where average reductions ranged from about 40 to 110 kg of carbon dioxide equivalent emissions per person per year. In China, the direction of impact is unclear, but the net change is likely to be small. Brazilian results were sensitive to parameter values and the direction and magnitude of impact is therefore uncertain. Despite the uncertainty, even small changes (positive or negative) in individual dietary emissions can produce large changes at the population level, arguing for the inclusion of the dietary pathway in greenhouse gas accounting of liquid biofuels.  相似文献   

6.
This paper examines the dynamics of energy investments and clean energy Research and Development (R&D) using a scenario-based modeling approach. Starting from the global scenarios proposed in the RoSE model ensemble experiment, we analyze the dynamics of investments under different assumptions regarding economic and population growth as well as availability of fossil fuel resources, in the absence of a climate policy. Our analysis indicates that economic growth and the speed of income convergence across countries matters for improvements in energy efficiency, both via dedicated R&D investments but mostly through capital-energy substitution. In contrast, fossil fuel prices, by changing the relative competitiveness of energy sources, create an economic opportunity for radical innovation in the energy sector. Indeed, our results suggest that fossil fuel availability is the key driver of investments in low carbon energy innovation. However, this innovation, by itself, is not sufficient to induce emission reductions compatible with climate stabilization objectives.  相似文献   

7.
Poor countries are more heavily affected by extreme weather events and future climate change than rich countries. One of the reasons for this is the so-called adaptation deficit, that is, limits in the ability of poorer countries to adapt. This paper analyses the link between income and adaptation to climate events theoretically and empirically. We postulate that the adaptation deficit may be due to two factors: A demand effect, whereby the demand for the good “climate security” increases with income, and an efficiency effect, which works as a spill-over externality on the supply-side: Adaptation productivity in high-income countries is enhanced because of factors like better public services and stronger institutions. Using panel data from the Munich Re natural catastrophe database we find strong evidence for a demand effect for adaptation to two climate-related extreme events, tropical cyclones and floods. Evidence on the efficiency effect is more equivocal. There are some indications that adaptation in rich countries might be more efficient, but the evidence is far from conclusive. The implication for research is that better data, in particular on adaptation effort, need to be collected to understand adaptation efficiency. In terms of policy, we conclude that inclusive growth policies (which boost adaptation demand) should be an important component of international efforts to close the adaptation deficit.  相似文献   

8.
Achieving the international 2 °C limit climate policy requires stringent reductions in GHG emissions by mid-century, with some countries simultaneously facing development-related challenges. South Africa is a middle-income developing country with high rates of unemployment and high levels of poverty, as well as an emissions-intensive economy. South Africa takes into account an assessment of what a fair contribution to reducing global emissions might be, and is committed to a ‘peak, plateau and decline' emissions trajectory with absolute emissions specified for 2025 and 2030, while noting the need to address development imperatives. This work utilizes an economy-wide computable general equilibrium model (e-SAGE) linked to an energy-system optimization model (TIMES) to explore improving development metrics within a 14 GtCO2e cumulative energy sector carbon constraint through to 2050 for South Africa. The electricity sector decarbonizes by retiring coal-fired power plants or replacing with concentrated solar power, solar photovoltaics and wind generation. Industry and tertiary-sector growth remains strong throughout the time period, with reduced energy intensity via fuel-switching and efficiency improvements. From 2010 to 2050, the model results in the unemployment rate decreasing from 25% to 12%, and the percentage of people living below the poverty line decreasing from 49% to 18%. Total energy GHG emissions were reduced by 39% and per capita emissions decreased by 62%.

Policy relevance

Lower poverty and inequality are goals that cannot be subordinated to lower GHG emissions. Policy documents in South Africa outline objectives such as reducing poverty and inequality with a key focus on education and employment. In its climate policy and Intended Nationally Determined Contribution (INDC), South Africa is committed to a peak, plateau and decline GHG emissions trajectory. As in many developing countries, these policy goals require major transformations in the energy system while simultaneously increasing affordable access to safe and convenient energy services for those living in energy poverty. The modelled scenario in this work focuses on employment and poverty reduction under a carbon constraint, a novel combination with results that can provide information for a holistic climate and development policy framework. This study has focused on the long term, which is important in generating clear policy signals for the necessary large-scale investments.  相似文献   

9.
Expansion in the world's human population and economic development will increase future demand for fish products. As global fisheries yield is constrained by ecosystems productivity and management effectiveness, per capita fish consumption can only be maintained or increased if aquaculture makes an increasing contribution to the volume and stability of global fish supplies. Here, we use predictions of changes in global and regional climate (according to IPCC emissions scenario A1B), marine ecosystem and fisheries production estimates from high resolution regional models, human population size estimates from United Nations prospects, fishmeal and oil price estimations, and projections of the technological development in aquaculture feed technology, to investigate the feasibility of sustaining current and increased per capita fish consumption rates in 2050. We conclude that meeting current and larger consumption rates is feasible, despite a growing population and the impacts of climate change on potential fisheries production, but only if fish resources are managed sustainably and the animal feeds industry reduces its reliance on wild fish. Ineffective fisheries management and rising fishmeal prices driven by greater demand could, however, compromise future aquaculture production and the availability of fish products.  相似文献   

10.
To a set of well-regarded international scenarios (UNEP’s GEO-4), we have added consideration of the demand, supply, and energy implications related to copper production and use over the period 2010–2050. To our knowledge, these are the first comprehensive metal supply and demand scenarios to be developed. We find that copper demand increases by between 275 and 350% by 2050, depending on the scenario. The scenario with the highest prospective demand is not Market First (a “business as usual” vision), but Equitability First, a scenario of transition to a world of more equitable values and institutions. These copper demands exceed projected copper mineral resources by mid-century and thereafter. Energy demand for copper production also demonstrates strong increases, rising to as much as 2.4% of projected 2050 overall global energy demand. We investigate possible policy responses to these results, concluding that improving the efficiency of the copper cycle and encouraging the development of copper-free energy distribution on the demand side, and improving copper recycling rates on the supply side are the most promising of the possible options. Improving energy efficiency in primary copper production would lead to a reduction in the energy demand by 0.5% of projected 2050 overall global energy demand. In addition, encouraging the shift towards renewable technologies is important to minimize the impacts associated with copper production.  相似文献   

11.
Undernutrition, obesity, climate change, and freshwater depletion share food and agricultural systems as an underlying driver. Efforts to more closely align dietary patterns with sustainability and health goals could be better informed with data covering the spectrum of countries characterized by over- and undernutrition. Here, we model the greenhouse gas (GHG) and water footprints of nine increasingly plant-forward diets, aligned with criteria for a healthy diet, specific to 140 countries. Results varied widely by country due to differences in: nutritional adjustments, baseline consumption patterns from which modeled diets were derived, import patterns, and the GHG- and water-intensities of foods by country of origin. Relative to exclusively plant-based (vegan) diets, diets comprised of plant foods with modest amounts of low-food chain animals (i.e., forage fish, bivalve mollusks, insects) had comparably small GHG and water footprints. In 95 percent of countries, diets that only included animal products for one meal per day were less GHG-intensive than lacto-ovo vegetarian diets (in which terrestrial and aquatic meats were eliminated entirely) in part due to the GHG-intensity of dairy foods. The relatively optimal choices among modeled diets otherwise varied across countries, in part due to contributions from deforestation (e.g., for feed production and grazing lands) and highly freshwater-intensive forms of aquaculture. Globally, modest plant-forward shifts (e.g., to low red meat diets) were offset by modeled increases in protein and caloric intake among undernourished populations, resulting in net increases in GHG and water footprints. These and other findings highlight the importance of trade, culture, and nutrition in diet footprint analyses. The country-specific results presented here could provide nutritionally-viable pathways for high-meat consuming countries as well as transitioning countries that might otherwise adopt the Western dietary pattern.  相似文献   

12.
The feasibility of two low-carbon society (LCS) scenarios, one with and one without nuclear power and carbon capture and storage (CCS), is evaluated using the AIM/Enduse[Global] model. Both scenarios suggest that achieving a 50% emissions reduction target (relative to 1990 levels) by 2050 is technically feasible if locally suited technologies are introduced and the relevant policies, including necessary financial transfers, are appropriately implemented. In the scenario that includes nuclear and CCS options, it will be vital to consider the risks and acceptance of these technologies. In the scenario without these technologies, the challenge will be how to reduce energy service demand. In both scenarios, the estimated investment costs will be higher in non-Annex I countries than in Annex I countries. Finally, the enhancement of capacity building to support the deployment of locally suited technologies will be central to achieving an LCS.

Policy relevance

Policies to reduce GHG emissions up to 2050 are critical if the long-term target of stabilizing the climate is to be achieved. From a policy perspective, the cost and social acceptability of the policy used to reduce emissions are two of the key factors in determining the optimal pathways to achieve this. However, the nuclear accident at Fukushima highlighted the risk of depending on large-scale technologies for the provision of energy and has led to a backlash against the use of nuclear technology. It is found that if nuclear and CCS are used it will be technically feasible to halve GHG emissions by 2050, although very costly. However, although the cost of halving emissions will be about the same if neither nuclear nor CCS is used, a 50% reduction in emissions reduction will not be achievable unless the demand for energy service is substantially reduced.  相似文献   

13.
Today Africa is a small emitter, but it has a large and faster-than-average growing population and per capita income that could drive future energy demand and, if unconstrained, emissions. This paper uses a multi-model comparison to characterize the potential future energy development for Continental and Sub-Saharan Africa under different assumptions about population and income. Our results suggest that population and economic growth rates will strongly influence Africa’s future energy use and emissions. We show that affluence is only one face of the medal and the range of future emissions is also contingent on technological and political factors. Higher energy intensity improvements occur when Africa grows faster. In contrast, climate intensity varies less with economic growth and it is mostly driven by climate policy. African emissions could account for between 5 % and 20 % of global emissions, with Sub-Saharan Africa contributing between 4 % and 10 % of world emissions in 2100. In all scenarios considered, affluence levels remain low until the middle of the century, suggesting that the population could remain dependent on traditional bioenergy to meet most residential energy needs. Although the share of electricity in final energy, electric capacity and electricity use per capita all rise with income, even by mid-century they do not reach levels observed in developed countries today.  相似文献   

14.
There is mounting evidence that major improvements in environmental quality in high-income countries over the past decades may have been achieved to a large degree through relocation of environmental impacts of consumption to other, usually poorer countries. While political and academic debates on appropriate policy interventions to address this challenge are gaining ground, we still know rather little about the drivers of international environmental impact shifting, other than international trade flows per se. We address this issue by focusing on the effects of economic inequality and political factors. We argue that income inequality between and within countries as well as variation in political institutions, environmental clauses in preferential trade agreements (PTAs), and participation in international environmental treaties could be important drivers or mitigators of environmental impact shifting between countries. We use novel panel data on five types of environmental impact flows between country dyads (187 countries, 1990–2015) to assess these arguments. We find that richer countries and countries with higher domestic economic equality tend to be the “outsourcers”, and poorer, domestically more unequal countries the “insourcers” of environmental impacts. Discrepancies in democracy levels aggravate the outsourcing from more equal to more unequal societies. In turn, environmental clauses in PTAs have a mitigating effect on environmental impact shifting, but participation in international environmental agreements has no such effect. Our findings highlight the need for green economy policies that reduce environmental footprints of consumption not only within high-income democracies, but also make their global supply chains more sustainable.  相似文献   

15.
Western diets are characterised by a high intake of meat, dairy products and eggs, causing an intake of saturated fat and red meat in quantities that exceed dietary recommendations. The associated livestock production requires large areas of land and lead to high nitrogen and greenhouse gas emission levels. Although several studies have examined the potential impact of dietary changes on greenhouse gas emissions and land use, those on health, the agricultural system and other environmental aspects (such as nitrogen emissions) have only been studied to a limited extent. By using biophysical models and methods, we examined the large-scale consequences in the European Union of replacing 25–50% of animal-derived foods with plant-based foods on a dietary energy basis, assuming corresponding changes in production. We tested the effects of these alternative diets and found that halving the consumption of meat, dairy products and eggs in the European Union would achieve a 40% reduction in nitrogen emissions, 25–40% reduction in greenhouse gas emissions and 23% per capita less use of cropland for food production. In addition, the dietary changes would also lower health risks. The European Union would become a net exporter of cereals, while the use of soymeal would be reduced by 75%. The nitrogen use efficiency (NUE) of the food system would increase from the current 18% to between 41% and 47%, depending on choices made regarding land use. As agriculture is the major source of nitrogen pollution, this is expected to result in a significant improvement in both air and water quality in the EU. The resulting 40% reduction in the intake of saturated fat would lead to a reduction in cardiovascular mortality. These diet-led changes in food production patterns would have a large economic impact on livestock farmers and associated supply-chain actors, such as the feed industry and meat-processing sector.  相似文献   

16.
Reducing hunger while staying within planetary boundaries of pollution, land use and fresh water use is one of the most urgent sustainable development goals. It is imperative to understand future food demand, the agricultural system, and the interactions with other natural and human systems. Studying such interactions in the long-term future is often done with Integrated Assessment Modelling. In this paper we develop a new food demand model to make projections several decades ahead, having 46 detailed food categories and population segmented by income and urban vs rural. The core of our model is a set of relationships between income and dietary patterns, with differences between regions and income inequalities within a region. Hereby we take a different, more long-term-oriented approach than elasticity-based macro-economic models (Computable General Equilibrium (CGE) and Partial Equilibrium (PE) models). The physical and detailed nature of our model allows for fine-grained scenario exploration. We first apply the model to the newly developed Shared Socio-economic Pathways (SSP) scenarios, and then to additional sustainable development scenarios of food waste reduction and dietary change. We conclude that total demand for crops and grass could increase roughly 35–165% between 2010 and 2100, that this future demand growth can be tempered more effectively by replacing animal products than by reducing food waste, and that income-based consumption inequality persists and is a contributing factor to our estimate that 270 million people could still be undernourished in 2050.  相似文献   

17.
Per capita consumption of plastic continues to increase and remains at high levels in high-income countries, despite obvious contributions to the global problem of plastics pollution. This paper attempts to provide an explanation for this phenomenon based on construal level theory, positing that plastic waste is a problem that is perceived as “out of sight and out of mind” for consumers in high plastic consumption (typically high income) countries and that this is influenced by the export of plastic waste to other (typically lower income and lower consumption) countries for disposal – shifting the burden of mismanaged plastic waste and perceptions of plastics pollution in the countries creating the majority of plastic waste. The apparent lack of plastics pollution in a local environment becomes a mediator, influenced by the export of plastic waste, which may then contribute to further plastics consumption. The theory is tested using structural equation modelling using rare, available matched data for mismanaged plastic waste, plastic waste exports, and plastics consumption at an aggregate country level. All study hypotheses are supported. The paper concludes with recommendations for future research and practice, including potential changes to government policy aimed at reducing future plastics consumption and pollution.  相似文献   

18.
Today, the agricultural sector accounts for approximately 15% of total global anthropogenic emissions, mainly methane and nitrous oxide. Projecting the future development of agricultural non-CO2 greenhouse gas (GHG) emissions is important to assess their impacts on the climate system but poses many problems as future demand of agricultural products is highly uncertain. We developed a global land use model (MAgPIE) that is suited to assess future anthropogenic agricultural non-CO2 GHG emissions from various agricultural activities by combining socio-economic information on population, income, food demand, and production costs with spatially explicit environmental data on potential crop yields. In this article we describe how agricultural non-CO2 GHG emissions are implemented within MAgPIE and compare our simulation results with other studies. Furthermore, we apply the model up to 2055 to assess the impact of future changes in food consumption and diet shifts, but also of technological mitigation options on agricultural non-CO2 GHG emissions. As a result, we found that global agricultural non-CO2 emissions increase significantly until 2055 if food energy consumption and diet preferences remain constant at the level of 1995. Non-CO2 GHG emissions will rise even more if increasing food energy consumption and changing dietary preferences towards higher value foods, like meat and milk, with increasing income are taken into account. In contrast, under a scenario of reduced meat consumption, non-CO2 GHG emissions would decrease even compared to 1995. Technological mitigation options in the agricultural sector have also the capability of decreasing non-CO2 GHG emissions significantly. However, these technological mitigation options are not as effective as changes in food consumption. Highest reduction potentials will be achieved by a combination of both approaches.  相似文献   

19.
Book review     
《Climate Policy》2013,13(4):395-396
In 2007 the US Congress began considering a set of bills to implement a cap-and-trade system to limit the nation's greenhouse gas (GHG) emissions. The MIT Integrated Global System Model (IGSM)—and its economic component, the Emissions Prediction and Policy Analysis (EPPA) model—were used to assess these proposals. In the absence of policy, the EPPA model projects a doubling of US greenhouse gas emissions by 2050. Global emissions, driven by growth in developing countries, are projected to increase even more. Unrestrained, these emissions would lead to an increase in global CO2 concentration from a current level of 380 ppmv to about 550 ppmv by 2050 and to near 900 ppmv by 2100, resulting in a year 2100 global temperature 3.5–4.5°C above the current level. The more ambitious of the Congressional proposals could limit this increase to around 2°C, but only if other nations, including developing countries, also strongly controlled greenhouse gas emissions. With these more aggressive reductions, the economic cost measured in terms of changes in total welfare in the United States could range from 1.5% to almost 2% by the 2040–2050 period, with 2015 CO2-equivalent prices between $30 and $55, rising to between $120 and $210 by 2050. This level of cost would not seriously affect US GDP growth but would imply large-scale changes in its energy system.  相似文献   

20.
This article simulates deep decarbonization pathways for a small open economy that lacks the usual avenues for large CO2 reductions – heavy industry and power generation. A computable general equilibrium model is used to assess the energy and economic impacts of the transition to only one ton of CO2 emissions per capita in 2050. This represents a 76% reduction with respect to 1990 levels, while the population is expected to be 46% larger and GPD to increase by 90%. The article discusses several options and scenarios that are compatible with this emissions target and compares them with a reference scenario that extrapolates already-decided climate and energy policy instruments. We show that the ambitious target is attainable at moderate welfare costs, even if it needs very high carbon prices, and that these costs are lower when either CO2 can be captured and sequestered or electricity consumption can be taxed sufficiently to stabilize it.

Policy relevance

In the context of COP 21, all countries must propose intended contributions that involve deep decarbonization of their economy over the next decades. This article defines and analyses such pathways for Switzerland, taking into consideration the existing energy demand and supply and also already-defined climate policies. It draws several scenarios that are compatible with a target of 1 ton of CO2 emissions per capita in 2050. This objective is very challenging, especially with the nuclear phase out decided after the disaster in Fukushima and the political decision to balance electricity trade. Nevertheless, it is possible to design several feasible pathways that are based on different options. The economic cost is significant but affordable for the Swiss economy. The insights are relevant not only for Switzerland, but also for other industrialized countries when defining their INDCs.  相似文献   


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