Higher total energy costs strain the elderly, especially low-income, across 31 developed countries.

Addressing the total energy cost burden of elderly people is essential for designing equitable and effective energy policies, especially in responding to energy crisis in an aging society. It is due to the double impact of energy price hikes on households-through direct impact on fuel bills and indirect impact on the prices of goods and services consumed. However, while examining the household energy cost burden of the elderly, their indirect energy consumption and associated cost burden remain poorly understood. This study quantifies and compares the direct and indirect energy footprints and associated total energy cost burdens for different age groups across 31 developed countries. It reveals that the elderly have larger per capita energy footprints, resulting from higher levels of both direct and indirect energy consumption compared with the younger age groups. More importantly, the elderly, especially the low-income elderly, have a higher total energy cost burden rate. As the share of elderly in the total population rapidly grows in these countries, the larger per capita energy footprint and associated cost burden rate of elderly people would make these aging countries more vulnerable in times of energy crises. It is therefore crucial to develop policies that aim to reduce energy consumption and costs, improve energy efficiency, and support low-income elderly populations. Such policies are necessary to reduce the vulnerability of these aging countries to the energy crisis.

Promoting Sustainable Development Goals by Optimizing City-Level Solar Photovoltaic Deployment in China.

Solar photovoltaic (PV) installations, which enable carbon neutrality, are expected to surge in the coming decades. This growth will support sustainable development goals (SDGs) via reductions in power-generation-related environmental emissions and water consumption while generating new jobs. However, where and to what extent PVs should be utilized to support SDGs must be thoroughly addressed. Here, we use multiple PV deployment scenarios to compare the benefits of PVs and related SDGs progress in 366 prefectural-level cities in China. We developed an assessment framework that integrates a PV allocation model, an electricity system optimization model, and a benefit assessment approach. We identify vast differences in PV distribution and electricity transmission and elucidate trade-offs and synergies among the SDGs under various PV implementation scenarios. The water conservation-oriented scenario yields substantial carbon reduction, air pollutant mitigation, and water saving cobenefits, leading to the greatest SDGs improvements. Prioritizing employment creation enhances job-relevant SDGs but inhibits environmental resource benefits. SDGs in less developed cities present greater progress across all scenarios. This study highlights the need to consider spatial heterogeneity and the potential trade-offs between different SDGs and regions when designing energy transition strategies.

Carbon Abatement and Leakage in China's Regional Carbon Emission Trading.

Emission trading schemes (ETS) are increasingly becoming a popular policy instrument to balance carbon abatement and economic growth. As a globally unified carbon pricing system has not yet been established, whether regionally operated ETSs cause carbon leakage remains a major concern. Taking China's regional pilot ETSs as a quasi-natural experiment, the study uses the spatial difference-in-differences method to examine how regional ETSs affect carbon emissions in and outside cities of policy implementation. Our analysis finds that China's regional ETS policy contributes to a 6.1% reduction in urban CO2 emissions and a 6.6% decline in emissions intensity in regulated cities, causing carbon leakages that increase CO2 emissions in neighboring cities by 1.7% on average. Our finding further suggests that regional ETSs mitigate local CO2 emissions through outsourcing production, improving energy efficiency and decarbonizing energy structure, whereas the outsourcing of industrial production drives up CO2 emissions in adjacent cities. Moreover, the performances of regional ETSs vary largely by socioeconomic context and mechanism design. China's regional ETSs reduce CO2 emissions more effectively in central and industrial cities but with more severe carbon leakage, while rigorous compliance mechanisms and active market trading help deepen carbon abatement and alleviate carbon leakage.

International Trade Reshapes the Decoupling of Emissions from Economic Growth.

Efforts to stabilize the global climate change while also continuing human development depend upon "decoupling" economic growth from fossil fuel CO2 emissions. However, evaluations of such decoupling have typically relied on production-based emissions, which do not account for emissions embodied in international trade. Yet international trade can greatly change emissions accounting and reshape the decoupling between emissions and economic growth. Here, we evaluate decoupling of economic growth from different accounts of emissions in each of the 159 countries and analyze the drivers of decoupling. We find that between 1995 and 2015, although 29 countries exhibited strong decoupling of territorial emissions (growing economies and decreasing emissions), only 19 countries achieved economic growth while their consumption-based emissions decreased. Most developed countries have achieved decoupling of emissions related to domestic goods and services, but have not achieved decoupling of emissions related to imported goods and services. The U-test confirms that the domestic component of consumption-based emissions exhibits a stronger decoupling trend from gross domestic product (GDP) growth than consumption-based emissions, and emissions from imports continue to rise with GDP per capita without a corresponding decline, providing a statistical validation of the decoupling analysis. Moreover, in the countries where economic growth and consumption-based emissions are most decoupled, a key driver is decreasing emissions intensity due to technological progress─and especially reductions in the intensity of imported goods and services. Our results reveal the importance of assessing decoupling using consumption-based emissions; successful decoupling may require international cooperation and coordinated mitigation efforts of trading partners.

Does interstate trade of agricultural products in the U.S. alleviate land and water stress?

Interregional free-trade of agricultural products is expected to transfer embodied (virtual) water from more to less water-productive regions. However, irrigation in semi-arid to arid regions may significantly push up agricultural productivity but cause local water scarcity. This may result in a puzzle: inter-regional trade may save overall water consumption but lead to more severe local water scarcity. An analogous puzzle may exist for farmland, for instance, trade may save farmland but not address farmland scarcity. To test the existence of these two important puzzles, we applied environmentally extended multi-regional input-output models to obtain the inter-regional virtual agricultural water and land transfer across 48 states of the conterminous U.S. and estimated their agricultural land and water footprints in 2017. Such a detailed analysis showed that while the land-abundant Midwestern states exported a sizable amount of virtual farmland to other densely populated areas and foreign nations, the water-stressed Western U.S. and Southwestern U.S. states, like California, Arizona, and New Mexico, exported considerable amounts of water-intensive crops such as fruits, vegetables and tree nuts to the Eastern U.S. and overseas, thus worsen the local water scarcity of those water scarce states. Our analysis highlights a critical dilemma inherent in an economic productivity-focused incentive regime: It frequently leads to increased withdrawal of scarce water. Therefore, resource scarcity rents need to be reflected in inter-regional trade with the support of local environmental policies.

Multiscale Analysis of the Relationship between Toxic Chemical Hazard Risks and Racial/Ethnic and Socioeconomic Groups in Texas, USA.

Although quantitative environmental (in)justice research demonstrates a disproportionate burden of toxic chemical hazard risks among racial/ethnic minorities and people in low socioeconomic positions, limited knowledge exists on how racial/ethnic and socioeconomic groups across geographic spaces experience toxic chemical hazards. This study analyzed the spatial non-stationarity in the associations between toxic chemical hazard risk and community characteristics of census block groups in Texas, USA, for 2017 using a multiscale geographically weighted regression. The results showed that the percentage of Black or Asian population has significant positive associations with toxic risk across block groups in Texas, meaning that racial minorities suffered more from toxic risk wherever they are located in the state. By contrast, the percentage of Hispanic or Latino has a positive relationship with toxic risk, and the relationship varies locally and is only significant in eastern areas of Texas. Statistical associations between toxic risk and socioeconomic variables are not stationary across the state, showing sub-state patterns of spatial variation in terms of the sign, significant level, and magnitude of the coefficient. Income has a significant negative association with toxic risk around the Dallas-Fort Worth-Arlington Metropolitan Statistical Area. Proportions of people without high school diploma and the unemployment rate both have positive relationships with toxic risk in the eastern area of Texas. Our findings highlight the importance of identifying the spatial patterns of the association between toxic chemical hazard risks and community characteristics at the census block group level for addressing environmental inequality.

Agricultural HANPP Embodied in Consumption: Tracing Pressure on Ecosystems Based on an MRIO Analysis.

Agriculture is one of humankind's most significant sources of biomass; it also places tremendous pressure on ecosystems through its increasing demand for agricultural products. However, few studies have assessed human pressures on ecosystems from agricultural production and consumption based on a whole-supply-chain perspective. Based on the concept of human appropriation of net primary productivity (HANPP), we evaluate trends of agricultural HANPP embodied in consumption from a global perspective and trace the pressure from agriculture production that is exerted on the environment using an environmentally extended multiregional input-output (MRIO) model. The results show that agricultural HANPP embodied in consumption accounted for over two-thirds of total HANPP but brought about less than 7% of global value added. India, Brazil, and China were found to have the highest level of agricultural HANPP embodied in consumption. Agricultural net exporters were found to usually be low- and lower-income countries, while net importers are found to be high-income countries. According to the driving factor analysis, high-income and low-income countries should cooperate by adjusting consumption patterns and sharing agricultural technology to alleviate the pressure from agricultural production. Our study highlights the importance of agrarian expertise sharing and the need to develop sustainable and green agricultural production.

Assessing Transboundary Impacts of Energy-Driven Water Footprint on Scarce Water Resources in China: Catchments under Stress and Mitigation Options.

The energy supply chains operating beyond a region's jurisdiction can exert pressure on the availability of water resources in the local area. In China, however, there is a lack of transboundary assessments that investigate the effects of energy consumption on water stress within and across river basins. In this study, we therefore investigate transboundary impacts on scarce water resources that are induced by energy demands (i.e., electricity, petroleum, coal mining, oil and gas extraction, and gas production). We develop a bottom-up high spatial resolution water inventory and link it to a 2017 multiregional input-output (MRIO) table of China to analyze supply chain scarce water use at provincial and river basin levels. We find that the energy-driven water footprint accounts for 21.6% of national water usage, of which 35.7% is scarce water. Nonelectric power energy sectors contribute to around half of the nation's scarce water transfer. We identify three sets of catchments whose water resources are stressed by energy demand, i.e., (a) from the northern Hai River Basin to the eastern part of the Yellow River Basin and the Huai River Basin, (b) the northern area of the Northwest Rivers, and (c) the developed coastal city clusters in the Yangtze River Basin and the Pearl River Basin. We then evaluate the impacts of eight mitigation options, which may potentially shift around half of the moderate- or high-stress areas in the Hai River Basin and the Northwest Rivers to low to moderate (or even low) stress. We highlight the need for transboundary collaboration to sustain water-constrained energy demand and to develop targeted measures to mitigate stress on water resources within a river basin.

Impact of International Trade on the Carbon Intensity of Human Well-Being.

There has been a longstanding debate about the impact of international trade on the environment and human well-being, yet there is little known about such environment and human well-being trade-off. Here, we explore the effect of international trade on the carbon intensity of human well-being (CIWB) globally under the current global trade system and a hypothetical no-trade scenario. We found that between 1995 and 2015, CIWB of 41% of countries declined and 59% of countries increased, caused by international trade, and this resulted in a reduction of the global CIWB and a decline in CIWB inequality between countries. International trade decreased CIWB for high- and upper-middle-income countries and increased CIWB for lower- and middle-income countries. In addition, our results also show that decreases in emission intensity are the most important driver of lower CIWB and the percentage contribution of emission intensity to the improvement in CIWB increases with income. The reduction of emission intensity, population growth, and increase in life expectancy all contribute to CIWB reduction, while the consumption level is the primary factor driving CIWB growth. Our results underscore the importance of studying the impact of international trade on the CIWB of countries at different stages of development.

Relocating Industrial Plants Delivers Win-Win Emission Reduction Benefits to Origin and Destination Regions.

Relocating pollution-intensive factories is one of the most effective measures to meet mandatory environmental regulations in developed cities while simultaneously imposing environmental pressure on the receiving cities. Existing studies often assume that relocated plants produce the same or higher emissions when relocated. However, the current pollution mitigation policies enforce even higher emission standards in the destination after plant relocation. We employ a bottom-up pollution accounting approach to assess the impact of intraregional or interregional relocation of iron and steel plants in China's Beijing-Tianjin-Hebei (BTH) area on various air pollutants; specifically, seven policy scenarios are modeled, based on stringency, implementation scope, and production technologies. We find that relocation combined with emission standards enforcement and shifts from BOF (basic oxygen furnace) to EAF (electric arc furnace) production technology may significantly reduce emissions within and outside BTH areas by as much as 28.8% compared to business as usual. The observed reduction is mainly due to the requirement of meeting ultralow emission standards directly or indirectly after relocation. Both origin and destination cities benefit from the relocation, with limited emission spillovers (+9.1%) for destinations outside BTH and even a net reduction (9.4%) in Tangshan. We conclude that combining factory relocation with stricter emission standards and production technological innovation could circumvent the Pollution Haven Hypothesis and deliver win-win air pollution reduction benefits for both origins and destinations.

Reduced carbon emission estimates from fossil fuel combustion and cement production in China.

Nearly three-quarters of the growth in global carbon emissions from the burning of fossil fuels and cement production between 2010 and 2012 occurred in China. Yet estimates of Chinese emissions remain subject to large uncertainty; inventories of China's total fossil fuel carbon emissions in 2008 differ by 0.3 gigatonnes of carbon, or 15 per cent. The primary sources of this uncertainty are conflicting estimates of energy consumption and emission factors, the latter being uncertain because of very few actual measurements representative of the mix of Chinese fuels. Here we re-evaluate China's carbon emissions using updated and harmonized energy consumption and clinker production data and two new and comprehensive sets of measured emission factors for Chinese coal. We find that total energy consumption in China was 10 per cent higher in 2000-2012 than the value reported by China's national statistics, that emission factors for Chinese coal are on average 40 per cent lower than the default values recommended by the Intergovernmental Panel on Climate Change, and that emissions from China's cement production are 45 per cent less than recent estimates. Altogether, our revised estimate of China's CO2 emissions from fossil fuel combustion and cement production is 2.49 gigatonnes of carbon (2 standard deviations = ±7.3 per cent) in 2013, which is 14 per cent lower than the emissions reported by other prominent inventories. Over the full period 2000 to 2013, our revised estimates are 2.9 gigatonnes of carbon less than previous estimates of China's cumulative carbon emissions. Our findings suggest that overestimation of China's emissions in 2000-2013 may be larger than China's estimated total forest sink in 1990-2007 (2.66 gigatonnes of carbon) or China's land carbon sink in 2000-2009 (2.6 gigatonnes of carbon).

Tension of Agricultural Land and Water Use in China's Trade: Tele-Connections, Hidden Drivers and Potential Solutions.

Interregional trade can potentially extend the management of scarce resources beyond a region's territory along supply chains. Here we combined the multiregional input-output model with structural decomposition analysis to reveal the distant connections of agricultural land and water use as well as the drivers behind their variations in China. Our results show that trade-embodied agricultural land use increase by 2.3-fold and 2.5-fold for virtual agricultural water use flows from 2002 to 2012. The water-starved northern China with abundant agricultural land is the main exporter of virtual (also called trade-embodied) agricultural land and water. Moreover, the role of the virtual water use importers and exporters were determined by the availability of land, rather than water resources. Based on scenario analysis, we found that if agricultural water use efficiency of north China reached the world's top-level but agricultural land use efficiency remained unchanged, the virtual water flows would be reduced by 32% and only water resources, not agricultural land, would be able to sustain future economic development. Our findings may provide significant information for potential solutions to China's regional water shortage from a land-water nexus perspective.

Drivers toward a Low-Carbon Electricity System in China's Provinces.

Decarbonization of the power sector is one of the most important efforts to meet the climate mitigation targets under the Paris Agreement. China's power sector is of global importance, accounting for ∼25% of global electricity production in 2015. The carbon intensity of China's electricity is still much higher than the global average, but the country has made important strides toward a low-carbon transition based on two main pillars: improvement of energy efficiency and decreasing the share of fossil fuels. By applying a decoupling indicator, our study shows that 21 provinces achieved a "relative decoupling" of carbon emissions and electricity production and the remaining nine provinces achieved "absolute decoupling" between 2005 and 2015. We updated China's emission factors based on the most recent data by also considering the quality of imported coal and compared our results with the widely used Intergovernmental Panel on Climate Change coefficients to show the sensitivity of results and the potential error. Our decomposition analysis shows that improvement of energy efficiency was the dominant driver for decarbonization of 16 provincial power sectors, while the access to low-carbon electricity and substitution of natural gas for coal and oil further accelerated their decarbonization.

Household carbon and energy inequality in Latin American and Caribbean countries.

Reducing inequality, eradicating poverty and achieving a carbon-neutral society are recognized as important components of the United Nations' Sustainable Development Goals. In this study, we focus on carbon and energy inequality between and within ten Latin American and Caribbean (LAC) countries. Detailed carbon and energy footprint were estimated by combining the consumption profiles (2014) in ten LAC countries with environmental extended multi-regional input-output (MRIO) analysis. Our results show significant inequality of regional total and per capita carbon and energy footprint across the studied LAC countries in 2014. The top 10% income category was responsible for 29.1% and 26.3% of the regional total carbon and energy footprint, and their per capita carbon and energy footprint were 12.2 and 7.5 times of the bottom 10% earners in that region. The average carbon footprint of studied LAC countries varied between 0.53 and 2.21 t CO2e/cap (ton of CO2 equivalent, per capita), and the energy footprint ranged from 0.38 to 1.76 t SOE/cap (ton of Standard Oil Equivalent, per capita). The huge difference in total and per capita carbon emissions and energy consumption of different income groups suggests notable differences in climate change responsibility, and supports policies for achieving sustainable consumption in terms of carbon tax, renewable energy subsidy, and decarbonizing the consumption structure in different LAC countries.

Impacts of Urban Expansion on Terrestrial Carbon Storage in China.

Urban expansion is one of the main factors driving terrestrial carbon storage (TCS) changes. Accurate accounting of TCS and rigorous quantification of its changes caused by historical urban expansion may help us to better predict its changes in the future. This study focuses on the carbon impacts of urbanization in China where the share of the urban population has increased from 18% in 1978 to 59% in 2017 and the growing will continue in the coming decades. Our results show that China's TCS decreased at an accelerating pace over the past three decades with an average reduction of 0.72TgC/y in 1980-1990 and 8.72TgC/y in 2000-2010, mostly due to conversion from cropland and woodland to urban land. Through simulating urban expansion under four scenarios from 2010 to 2050, we found a potential increasing trend in land conversion from woodland to urban land. This conversion trend would result in carbon storage loss at an average rate of 9.31TgC/y ∼ 12.94TgC/y in 2010-2050. The increasing trend in both land conversion and carbon storage loss is especially visible in the population centers of the Yangtze River Delta and the Pearl River Delta. Considering that the indirect emission effects of urbanization, such as farmland displacement, population migration, and land degradation, may be much larger, the overall emission impact of forthcoming urban expansion in China would increase the uncertainty of the nation's carbon emissions and potentially undermine China's targets as committed in the Paris Climate Agreement.

The determinants of China's national and regional energy-related mercury emission changes.

As the world's largest energy-related mercury emitter, proper reduction policy is urgently needed in China. However, a quantitative analysis on how different factors affect China's national and regional mercury emissions has been lacking, which hinders the design and implementation of mercury control strategies. To fill the knowledge gap, this study applies a temporal and spatial logarithmic mean divisia index (LMDI) model to reveal the important determinants of mercury emissions across China from 2007 to 2015. The results show a descendant trend generally in energy-related mercury emissions at both national and regional level. Economic scale is the main driving factor while its effect is largely offset by the decreasing mercury emission and energy intensities. However, Jiangsu and Shanxi in 2012-2015 are exceptions with emission growth because of their rebounded emission factors and energy intensities. Moreover, a decoupling effect between energy-related mercury emissions and GDP growth is found, reflecting that there is ongoing green energy transition in China. The spatial decomposition verifies that effects of economic scale and energy intensity are the mainly determinants for mercury emission differences between national average and provincial emissions. Other factors' effects are prominent in several provinces such as Xinjiang, Chongqing and Heilongjiang, where the emission gap is primarily resulted by the differences between national and local mercury intensities. By identifying the determinants of emission changes as well as the differences between the national average and provincial emissions, this study provides insights for formulating more targeted mercury mitigation strategies.

Environmental impacts of dietary quality improvement in China.

Dietary-related risks rank top among all the health risks in many countries. The 2nd United Nations Sustainable Development Goal aims to end hunger, achieve food security and improved nutrition and promote sustainable agriculture. Yet whether improving nutritional quality also benefits the environment is still under-explored, particularly for developing countries. China is an interesting and important case because of its rapidly changing dietary patterns distinct from the western countries studied in the literature, sub-national level heterogeneity, socio-economic characteristics and lifestyles, as well as its considerable population. This paper evaluates greenhouse gas (GHG) emissions, water consumption, and land appropriation resulting from shifting the Chinese population to healthy diets. We quantify the environmental impacts of individual diets using the latest available data of China Health and Nutrition Survey (2011), and compare them with the environmental impacts of suggested healthy dietary patterns in accordance with the 2016 Chinese Dietary Guidelines. If all Chinese would follow healthy diets rather than their current diets revealed in the survey, GHG emissions, water consumption, and land occupation would increase by 7.5% (63.9 Mt CO2e annually), 53.5% (510 billion m3), and 54.2% (1256 billion m2), respectively. Urban and high-income groups have higher diet-related environmental impacts but could achieve less additional environmental impacts when moving to healthier diets. These findings indicate an expense of increased GHG emissions, and consumption of water and land resources in improving health. They also highlight the need to focus on the effects of improved economic conditions and urbanization in reconciling environmental impacts and human nutritional adequacy.

Kazakhstan's CO2 emissions in the post-Kyoto Protocol era: Production- and consumption-based analysis.

The first commitment period of the Kyoto Protocol came to an end in 2012 and more developing countries began to participate in the new phase of world carbon emission reduction. Kazakhstan is an important energy export country and a pivot of the "Belt and Road Initiative" (BRI). Despite its emissions are relatively small compared with huge emitters such as China and the US, Kazakhstan also faces great pressure in terms of CO2 emission reduction and green development. Accurately accounting CO2 emissions in Kazakhstan from both production and consumption perspectives is the first step for further emissions control actions. This paper constructs production-based CO2 emission inventories for Kazakhstan from 2012 to 2016, and then further analyses the demand-driven emissions within the domestic market and international trade (exports and imports) using environmentally extended input-output analysis. The production-based inventory includes 43 energy products and 30 sectors to provide detailed data for CO2 emissions in Kazakhstan. The consumption-based accounting results showed that certain sectors like construction drive more emissions and that the fuel consumption in different sectors varies. Furthermore, Russia and China are major consumers of Kazakhstan's energy and associated emissions, with the construction sector playing the most important role in it. The results suggested that both technology and policy actions should be taken into account to reduce CO2 emissions and that the BRI is also a good chance for Kazakhstan to develop a "Green Economy".

Virtual flows of aquatic heavy metal emissions and associated risk in China.

Heavy metal pollution is posing a serious threat to ecosystem and human health in China. In addition to being emitted into the atmosphere, heavy metals generated by industrial processes are also emitted into water bodies. However, there is a lack of research exploring trade-induced aquatic heavy metals (AHM) emissions hidden in cross-regional supply chain networks. Such information can provide both consumer and producer perspectives on stakeholders' responsibility and involve them in pollution control along the entire supply chain including influencing consumption choices. Using a bottom-up AHM emission inventory (including mercury (Hg), cadmium (Cd), chromium (Cr), arsenic (As), and lead (Pb)) in 2010, we firstly accounted for production- and consumption-based AHM emissions and their virtual flows between China's 30 provinces. Additionally, we developed an integrated index, i.e. Equal Risk Pollution Load, to measure the risk associated with five AHM based on the corresponding reference dose. We found that richer provinces Guangdong, Jiangsu and Zhejiang through their consumption of metal products caused aquatic Hg, Cd, As and Pb pollution in provinces with nonferrous-metallic mineral resources such as Hunan, Yunnan, and Inner Mongolia. However, virtual aquatic Cr emissions were incurred in richer coastal regions (e.g. Guangdong, Zhejiang) for producing and exporting high value added products (electroplated products, printed circuit board and leather products) to less developed inland provinces. Finally, we propose measures from a supply chain perspective to mitigate aquatic pollution.