20253 research outputs found
Sort by
Clean Air for Hanoi: What will it Take?
Get PDFVietnam has achieved great progress in both economic growth and poverty reduction; nevertheless, this economic growth is accompanied by an increase in resource use and other negative externalities, such as air pollution. This contributes significantly to environmental degradation and public health issues, particularly regarding air quality in some major cities in the country, including Hanoi, the capital of Vietnam. The current air quality situation in Hanoi and its neighboring provinces of Bac Ninh and Hung Yen necessitates urgent action to reduce pollution levels, and, consequently, population exposure to harmful PM2.5 concentrations. Newly announced air quality-related policies, which will be in effect between 2021 and 2030, are an important step towards decreasing air pollution but do not appear to be sufficient to protect health in the medium-term, that is, until 2030. To explore management options available to policy makers in the near term, this study has developed new data and alternative scenarios analyzing the impact of various air quality measures and policies. Opportunities to achieve national standards across Hanoi and its surrounding areas were identified and provide input into policy discussions on an Air Quality Management (AQM) Plan for Hanoi and its surrounding provinces, as well as for Vietnam in general
National Land-based Climate Mitigation Scenarios Dataset
Get PDFGiven the need to reduce greenhouse gases emissions to meet the 2 °C or 1.5 °C target of the Paris Agreement, over 150 countries currently have net-zero targets. National inventories and projections of land-based emissions and mitigation strategies have not been well developed and remain limited compared to energy sectors. Here, we provide worldwide national land-based emission and mitigation scenario data with a detailed portfolio of mitigation options. This information contributes to filling the gap between integrated assessment model estimates and national greenhouse gas inventories for land-based emissions through estimation of carbon sequestration in managed forests. Second, these data can be used as a benchmark for countries developing national targets or strategies for agriculture, forestry, and other land use sectors as well as for reviewing national contributions in global assessments in a manner consistent with integrated assessment model estimates
Prospective metal requirements assessment of China's wind-power and photovoltaics: Implications for emerging anthropogenic mines
No full textChina's carbon neutrality target requires large-scale deployment of wind-power and photovoltaics (PV) technologies. The uncertainties of their pathways will not only trigger potential metal supply-demand mismatch, but also hinder the better understanding of future anthropogenic mines. Here, we conducted a prospective assessment of metal requirements under multi-model comparison framework (MMCF). The results show that:(1) The installed capacities of China's wind-power and PV are 1900 GW respectively 3100 GW by 2060 averagely under MMCF. (2) Overall metal requirement of China's wind-power and PV sector is estimated at 0.88–1.38 billion tons from 2000 to 2060. (3) The scale of anthropogenic mine in China's wind-power and PV sector is around 0.56–0.72 billion tons by 2060. (4) Secondary base metals and scarce metals account for 19–21 % respectively 23–26 % of total metal inflow when the contribution of metal recyling is taken into consideration. We highlight that the policies of energy-metal nexus are neglected nowadays, while they need strengthening to deal with the issue of emerging anthropogenic mines in energy sector
Revisiting the role of education in attitudes toward immigration in different contexts in Europe
Get PDFAmong the individual determinants of attitudes toward immigration, the liberalising role of education is well known—those with higher levels of education tend to be more in favour of immigration. However, recent socioeconomic changes and idiosyncratic differences between European countries prompt us to reassess the role of education, given these contextual differences. Does it still apply, and is it universal? Moreover, does this relationship apply to both cultural and economic attitudes toward immigration? Using data from the European Social Survey, we analyse the role of education and socioeconomic changes in shaping economic and cultural attitudes toward immigration in 15 European countries over 16 years using a hierarchical model with cross-classified random effects. In our analysis, we distinguish between Eastern European and non-Eastern European countries. Our results indicate a robust positive and significant association between higher levels of education and more tolerant attitudes toward immigration in both aspects. However, they also reveal that the strength of this relationship varies between the two attitudes by context and region. For example, higher migrant inflow rates attenuate education’s liberalising and empowering role in shaping cultural attitudes in non-Eastern European countries but are not significant in Eastern European countries. Thus, our findings contribute to the literature examining the role of context in the established relationship between education and immigration attitudes while providing insights into regional differences
Contributions of countries without a carbon neutrality target to limit global warming
Get PDFBioenergy with carbon capture and storage (BECCS) is a key negative emission technology for climate mitigation. Some countries have made no commitment to carbon neutrality but are viewed as potential BECCS candidates (hereafter, non-CN countries). Here we analyze contributions of these countries to global climate mitigation with respect to BECCS using an Earth system model with explicit representations of bioenergy crops. Switchgrass cultivation in these non-CN countries can further remove atmospheric CO2 by 9.1 ± 2.8 and 19.9 ± 5.2 PgC in the low-warming and overshot scenarios, resulting in an extra biogeochemical cooling effect of 0.01 ± 0.04 to 0.02 ± 0.06 °C. This cooling is largely counterbalanced by the biophysical warming, but the net effect is still an extra cooling. The non-CN countries play a more important role in the low-warming scenario than in the overshoot scenario, despite the inequality of temperature change among countries. Our study highlights the importance of a global system for climate mitigation
An eco-physiological model of forest photosynthesis and transpiration under combined nitrogen and water limitation
Get PDFAlthough the separate effects of water and nitrogen (N) limitations on forest growth are well known, the question of how to predict their combined effects remains a challenge for modeling of climate change impacts on forests. Here, we address this challenge by developing a new eco-physiological model that accounts for plasticity in stomatal conductance and leaf N concentration. Based on optimality principle, our model determines stomatal conductance and leaf N concentration by balancing carbon uptake maximization, hydraulic risk and cost of maintaining photosynthetic capacity. We demonstrate the accuracy of the model predictions by comparing them against gross primary production estimates from eddy covariance flux measurements and sap-flow measurement scaled canopy transpiration in a long-term fertilized and an unfertilized Scots pine (Pinus sylvestris L.) forest in northern Sweden. The model also explains the response to N fertilization as a consequence of (i) reduced carbon cost of N uptake and (ii) increased leaf area per hydraulic conductance. The results suggest that leaves optimally coordinate N concentration and stomatal conductance both on short (weekly) time scales in response to weather conditions and on longer time scales in response to soil water and N availabilities
Learning, economies of scale, and knowledge gap effects on power generation technology cost improvements
Get PDFCost reductions are essential for accelerating clean technology deployment. Because multiple factors influence costs, traditional one-factor learning models, solely relying on cumulative installed capacity as an explanatory variable, may oversimplify cost dynamics. In this study, we disentangle learning and economies of scale effects at unit and project levels and introduce a knowledge gap concept to quantify rapid technological change's impact on costs. Our results show that a substantial proportion of cost declines in several technologies is attributable to economies of scale rather than learning processes. Thus, relying on one-factor learning may underestimate cost declines during upscaling periods for technologies with strong economies of scale effects and overestimate reductions for those approaching maximum size. Notably, the knowledge gap concept can endogenously capture how rapidly technology sizes can evolve through learning. These insights can improve decision-making and highlight the benefits of separating learning and economies of scale effects to estimate technology costs
Warming Promotes Nitrogen and Carbon Cycles in Global Grassland
No full textGrasslands, standing as one of Earth’s major ecosystems, offer numerous services vital to human well-being. The productivity of grasslands hinges on the availability of soil reactive nitrogen, which is highly sensitive to climatic variations. Using an extensive synthesis of 1242 experimental observations, reinforced by multiple models, we show that warming as a single driver of climate change intensifies nitrogen dynamics in grasslands. This could lead to increases in net primary productivity of 1% to 9% and escalate nitrogen leakage into the environment by 22% to 141%. Under the warming SSP2-4.5 scenario, we foresee an annual boost of 17 million tons per year (Tg yr–1) of nitrogen inputs, predominantly via biological nitrogen fixation, compared to the baseline scenario by 2050. Total nitrogen harvest is projected to climb by 12 Tg yr–1. However, the nitrogen surplus surge is expected to increase by 5 Tg yr–1, potentially intensifying nitrogen pollution. To counter this, adaptation measures must aim at curtailing reactive nitrogen losses while preserving increased nitrogen harvest. This could reduce nitrogen input and surplus by 10 and 20 Tg yr–1, respectively, while boosting nitrogen harvest by 10 Tg yr–1, potentially yielding economic gains of up to 121 billion USD by 2050. In shaping climate change adaptation policies, it is critical to balance the potential benefits and drawbacks of forging effective management approaches
Representing gender inequality in scenarios improves understanding of climate challenges
Get PDFAchieving gender equality can increase societies’ capacities to deal with climate change. Here we highlight empirical connections between gender equality and climate change adaptation and mitigation to propose a structured and detailed inclusion of gender-related aspects in the Shared Socioeconomic Pathway framework. The introduction of hypothetical pathways of gender (in)equality in the scenario space can help analyse interactions with other socioeconomic drivers and subsequent implications for adaptation and mitigation options. The extent of challenges to climate change adaptation and mitigation may substantially change depending on the rate at which societies progress towards equal access to resources and opportunities for self-realization for all genders. We propose steps that the scenario community could take to enrich the next generation of socioeconomic pathways
Electricity- and hydrogen-driven energy system sector-coupling in net-zero CO2 emission pathways
Get PDFElectricity- and hydrogen-based sector coupling contributes to realizing the transition towards greenhouse gas neutrality in the European energy system. Energy system and integrated assessment models show that, to follow pathways compatible with the European policy target of net-zero greenhouse gas emissions by 2050, large amounts of renewable electricity and H2 need to be generated, mostly by scaling-up wind and solar energy production capacity. With a set of such models, under jointly adopted deep decarbonisation scenario assumptions, we here show that the ensuing direct penetration of electricity and H2 in final energy consumption may rise to average shares of around 60% and 6%, respectively, by 2050. We demonstrate that electrification proves the most cost-efficient decarbonisation route in all economic sectors, while the direct use of H2 in final energy consumption provides a relatively small, though essential, contribution to deep decarbonisation. We conclude that the variance observed across results from different models reflects the uncertainties that abound in the shape of deep decarbonisation pathways, in particular with regard to the role of H2