Climate Benefits Research Articles

Climate change impacts of e-fuels for aviation in Europe under present-day conditions and future policy scenarios

‘E-fuels’ or ‘synthetic fuels’ are hydrocarbon fuels synthesized from hydrogen (H2) and carbon dioxide (CO2), where H2 can be produced via electrolysis of water or steam reforming of natural gas, and CO2 is captured from the combustion of a fossil or biogenic source or directly from the atmosphere. E-fuels are drop-in substitutes for fossil fuels, but their climate change mitigation benefits are largely unclear. This study evaluates the climate change impacts of e-fuels for aviation by combining different sources of CO2 and H2 up to 2050 under two contrasting policy scenarios. The analysis includes different climate metrics and the effects of near-term climate forcers, which are particularly relevant for the aviation sector. Results are produced for European average conditions and for Poland and Norway, two countries with high and low emission intensity from their electricity production mix. E-fuels can either have higher or lower climate change impacts than fossil fuels, depending on multiple factors such as, in order of importance, the electricity mix, the origin of CO2, the technology for H2 production, and the electrolyzer efficiency. The climate benefits are generally higher for e-fuels produced from CO2 of biogenic origin, while e-fuels produced from CO2 from direct air capture or fossil fuel combustion require countries with clean electricity to outperform fossil fuels. Synthetic fuels produced from H2 derived from natural gas have higher impacts than fossil fuels even when coupled with carbon capture and storage, if CO2 is sourced from fossil fuels or the atmosphere. Climate change impacts of e-fuels improve in the future, and they can all achieve considerable climate change mitigation in 2050relative to fossil jet fuel, provided that strict climate policy measures are implemented to decarbonize the electricity sector. Under reduced policy efforts, future climate impacts in 2050 of e-fuels from atmospheric or fossil CO2 are still higher than those of fossil jet fuels with an average European electricity mix. This study shows the conditions to maximize the climate change mitigation benefits of e-fuels, which essentially depend on progressive decarbonization of the electricity sector and on reduced use of CO2 sourced from fossil fuels.

Adapting ecosystem restoration for sustainable development in a changing world

Adapting ecosystem restoration for sustainable development in a changing world

De-Fueling Externalities: Causal Effects of Fuel Taxation and Mediating Mechanisms for Reducing Climate and Pollution Costs

De-Fueling Externalities: Causal Effects of Fuel Taxation and Mediating Mechanisms for Reducing Climate and Pollution Costs

Plants of place: justice through (re)planting Aotearoa New Zealand’s urban natural heritage

Climate change has led to urgent calls for environmental action and justice, which is likely to include increased urban vegetation. The benefits of this planting could go beyond ecological and climate benefits to contribute to decolonisation and environmental and spatial justice and build on the well-documented links between ecological and human wellbeing. In Aotearoa New Zealand, past and ongoing injustices resulting from colonisation have disconnected Māori (the Indigenous people) from their land. Māori see themselves reflected in the landscape and te taiao (the natural world). The process of colonisation has mostly erased natural heritage, intrinsic to Māori identity, from urban areas. Many plants in urban areas represent colonial identity rather than this natural heritage, and many of the native plants that have been planted originate from other parts of the country. Through reviewing the literature, this article argues for research that determines the benefits of urban planting design prioritising plants that naturally occurred in the past, termed here ‘plants of place’, in public places. In settler colonial countries, where it is an accepted practice to acknowledge built and predominantly colonial heritage, making pre-colonial natural heritage visible can have many co-benefits. It has the potential to contribute to climate change mitigation and adaptation, decolonisation efforts, spatial justice and environmental justice. Celebrating natural heritage and planting ‘plants of place’ can contribute in some part to righting past injustices and preparing for a changing future.

An Assessment of the Climate Damage Costs of European Short-Lived Climate Forcers

AbstractIn addition to effects from greenhouse gases, climate change is affected by short-lived climate forcers (SLCF). These are often co-emitted with carbon dioxide, and some are regulated air pollutants. In the governance of these pollutants, established estimates of damage costs of pollution inform benefit–cost analyses. However, climate change impact of SLCFs is omitted from these estimates. The purpose of this study is to calculate economic damage costs of air pollutants’ effect on climate change and compare these with established damage costs. Focus is on European emissions governed in the EU National Emission Reduction Commitments Directive during 2020–2050. We use well-known SLCF emission metrics and multiply with literature values on social costs of methane to calculate climate damage costs of SLCFs. The results indicate that average absolute climate damage costs are highest for black carbon ($59,500/ton in 2050) and lowest for nonmethane volatile organic compounds ($661/ton). Our indicative values are likely underestimations. Indicative climate damage costs are usually lower than established damage costs, with notable exceptions. We propose that more detailed studies are necessary, and that inclusion of climate damage costs into economic valuation of SLCFs is important for future air pollution and climate benefit–cost analyses.

Strategic uses for ancillary bioenergy in a carbon-neutral and fossil-free 2050 European energy system

Biomass is a growing renewable energy source in Europe and is envisioned to play a role for realising carbon neutrality, predominantly using dedicated energy crops. However, dedicated biomass is controversial for reasons including its competition with food production or its land-use and emissions impacts. Here we examine the potential role of a land-free alternative: ancillary bioenergy (AB) from biomass sources not primarily grown for energy and without land/food/feed competition. We provide the first dataset of 2050 ancillary biomass potential using the agricultural system model SOLm, which encompasses untapped by-/co-products and detailed agricultural residues. Results show that there is a limited future potential for AB in Europe (2394–10 342 PJ, which is 3–6 times lower than other estimates including dedicated biomass). We design and investigate alternative scenarios where this bioenergy resource can be fully utilised, not utilised at all, or utilised optimally by the sector-coupled energy system model Euro-Calliope. We find that fully utilising ancillary biomass can help phase out controversial nuclear or land-intensive dedicated biomass, so might achieve higher societal acceptability. Using all ancillary biomass as a negative-emissions source at stationary bioenergy carbon capture and storage plants in a nuclear-free system provides additional climate benefits. It is also possible to leave the AB potential completely unused, which barely increases total system cost, but would preserve agricultural nutrients. We conclude that there are synergies and trade-offs among possible strategic uses of AB, which can provide guidelines for a more coherent European bioenergy strategy. Although the 2050 potential of AB is limited, our findings suggest that it could fill critical strategic niches for realising carbon-neutrality.

Economic and environmental assessment of asphaltene-derived carbon fiber production

The asphaltene-derived carbon fiber production route demonstrates significant potential, emerging as a highly cost-effective alternative with promising climate benefits compared to the incumbent carbon fiber production methods.

A laboratory assessment of how biomass pellets could reduce indoor air pollution, mitigate climate change and benefit health compared to other solid fuels used in Ghana

To reduce indoor air pollution, the government of Ghana in 2019 formulated the renewable energy master plan to help disseminate biomass pellets and stoves to 2,000,000 households by 2030. But pellets have neither been included in Ghana's energy mix nor have their surmised climate and health benefits been empirically assessed. This laboratory study tested emissions by burning wood, charcoal and pellets in improved cookstoves. It further modelled their associated indoor air pollution reduction, personal exposure, health benefits and climate impact for comparison. The emission factors based on useful energy delivered of CO, CO2 and PM2.5 were 3.506 ± 0.704, 306.6 ± 43.35, and 0.229 ± 0.039 g/MJdelivered, respectively, for wood rocket 1 stove; 2.115 ± 0.695, 272.8 ± 16.70, and 0.256 ± 0.166 g/MJdelivered for wood rocket 2 stove; 4.820 ± 1.098, 205.3 ± 60.49, and 0.051 ± 0.044 g/MJdelivered for charcoal 1 stove; 4.474 ± 1.525, 221.8 ± 65.71, 0.043 ± 0.040 g/MJdelivered for charcoal 2 stove; and 0.511 ± 0.325, 338.1 ± 45.41, and 0.041 ± 0.023 g/MJdelivered for pellet stove. The forced air supplied by the gasifier stove reduced pollutant emissions from pellet combustion. The 100-year global warming contribution of the pellet stove was lower than that of charcoal stoves, and was influenced by upstream emissions of fuel processing. The WHO (World Health Organization) models showed that a complete transition from wood to pellets in one million households could significantly improve health with most benefits for children below five years. However, the reported benefits can only be achieved if pellets are added to Ghana's energy mix. The government of Ghana can ensure a sustained adoption of pellets by fostering market enablers for supply and demand of pellets and gasifier stoves, and mitigating the factors that impact pellet production and use. Field evaluation of the economic, health and climate co-benefits of using pellets in Ghana is recommended for future study.

Economic and biophysical limits to seaweed farming for climate change mitigation

Net-zero greenhouse gas (GHG) emissions targets are driving interest in opportunities for biomass-based negative emissions and bioenergy, including from marine sources such as seaweed. Yet the biophysical and economic limits to farming seaweed at scales relevant to the global carbon budget have not been assessed in detail. We use coupled seaweed growth and technoeconomic models to estimate the costs of global seaweed production and related climate benefits, systematically testing the relative importance of model parameters. Under our most optimistic assumptions, sinking farmed seaweed to the deep sea to sequester a gigaton of CO2 per year costs as little as US$480 per tCO2 on average, while using farmed seaweed for products that avoid a gigaton of CO2-equivalent GHG emissions annually could return a profit of $50 per tCO2-eq. However, these costs depend on low farming costs, high seaweed yields, and assumptions that almost all carbon in seaweed is removed from the atmosphere (that is, competition between phytoplankton and seaweed is negligible) and that seaweed products can displace products with substantial embodied non-CO2 GHG emissions. Moreover, the gigaton-scale climate benefits we model would require farming very large areas (>90,000 km2)—a >30-fold increase in the area currently farmed. Our results therefore suggest that seaweed-based climate benefits may be feasible, but targeted research and demonstrations are needed to further reduce economic and biophysical uncertainties.

Lower Carbon, Stronger Nation: Exploring Sociopolitical Determinants for the Chinese Public's Climate Attitudes.

Although numerous studies have examined the Chinese public's attitudes towards climate change, few have shed light on how sociopolitical factors related to the policy and the state have shaped such attitudes. This constituted our research goal. Against the background of China's Dual Carbon Goals, a national survey (n = 1469) was conducted to investigate the relationships between climate attitudes and climate benefit perception, institutional trust, policy familiarity, nationalism, and environmental values. Findings showed that respondents shared a high score of nationalism and a high level of trust in Chinese institutions. Their national benefit perception of climate action, nationalism, and trust in national institutions were strong determinants of their attitudes towards climate change. The findings suggested that for many Chinese, a lower-carbon future will be accompanied by a coming stronger nation, which is a key driver for people to adopt positive attitudes towards addressing climate change. As such, the current study revealed an alternative landscape of the determinants underlying people's attitudes towards climate change. To our knowledge, this is the first scholarly effort in China to empirically demonstrate the predictive role of nationalistic value in shaping climate attitudes and is one of the earliest efforts in climate communication to test the impact of the policy on such attitudes.

How does sharing economy advance cleaner production? Evidence from the product life cycle design perspective

The sharing economy is a recent worldwide development; however, its impact on sustainability remains unclear, particularly in regards to the advancement of cleaner production. In order to explore the potential and contribution of specific sharing economy business practices in the transition to cleaner production, this study empirically analyzed how China's free-floating bike-sharing (FFBS) improved environmental sustainability through optimization of product life cycle design. Specifically, the impact on climate change and human health of three generations of shared bike products was quantitatively analyzed by using product environmental footprint (PEF) approach. The results show that sustainable product lifecycle design can effectively improve the sustainability of FFBS. Through optimized design and product upgrades, the environmental impact intensity of FFBS has decreased by approximately 25.09% –34.34%. This causes FFBS to gradually evolve from exerting negative impacts on climate change to achieving considerable climate benefits (22.18 CO2-eq/pkm). The environmental benefits on ozone depletion and photochemical ozone formation also increased by about 2.46 μg CFC11eq/pkm and 85.77 mg NMVOC eq/pkm with the upgrade of shared bikes from the first generation to the third generation. In addition, although the negative effects of FFBS on respiratory inorganics, non-cancer human health effects and cancer human health effects have been significantly reduced, the corresponding positive environmental benefits still need to be achieved by significantly increasing the utilization rate of shared bikes. Furthermore, this suggests that the sustainable production life cycle design of FFBS can follow the principles of safety, ease of maintenance, durability, ease of use, universality, resource conservation, and recyclability. This empirical study can not only help authorities, managers and the public better understand the contribution of the sharing economy to cleaner production, but also provides new insights and valuable references for improving the sustainability of the sharing economy.

Experimental study on the temperature-regulating function of road thermoelectric generator system

Road thermoelectric generator systems (RTEGSs) can convert the heat absorbed by asphalt pavement into electricity. In addition, they can regulate the temperature of the asphalt pavement, which could be useful in reducing the urban heat-island effect in summer and melting snow in winter. Along these lines, in this work, the development of a novel type of RTEGS was proposed and its power-generation and temperature-regulation characteristics in summer and winter using outdoor tests were systematically explored. In summer, the pavement surface temperature was reduced by up to 10 °C using a water bath temperature of 25 °C and water-flow rate of 2.0 L/min. In winter, with the utilization of a water bath temperature of 20 °C and a water-flow rate of 2.5 L/min, snow could be melted within 44 min. Moreover, the peak output power of RTEGS was 162.33 mW and 34.63 mW in summer (ΔT = 37.3 °C) and winter (ΔT = 13.7 °C), respectively. Hence, this type of RTEGS can provide climatic and safety benefits, while also heat could be converted into useful energy.

Intensity and number of thinning operations affect the response of Eucalyptus grandis to water availability and extreme drought events

Climate change has induced an increase in the frequency and intensity of droughts and heat waves, reducing growth and increasing the mortality risk of both natural and planted forests. Management practices are expected to affect the capacity of stands to tolerate these new and fluctuating environmental conditions. Particularly, the effect of thinning on growth and mortality responses to climatic variation is highly variable among species and environmental conditions, and very few studies have been carried out in broad-leaved species. The objectives of this study were to assess the effect of forest thinning on (1) the growth sensitivity of planted Eucalyptus grandis to typical interannual variation in water availability and (2) its response to extreme drought events. We analyzed data collected in the period 1999–2016 from three thinning trials installed in sites with normal growth conditions of the species in a subtropical, humid and warm region of South America (Mesopotamia region, Argentina), where it is the most planted Eucalyptus species. Different intensities (final densities between 300 and 1250 plants/ha) and modalities (single- versus two-stage) of thinning operations were applied in each trial. First, we used a hierarchical linear model to relate basal area increment to water balance, and from this analysis we obtained the mean growth and sensitivity to water balance at individual, treatment and site levels. Results at the treatment level show that the mean growth of E. grandis increases with thinning intensity while its sensitivity to water balance decreases, consistently across all sites. At the individual level, using Hegyi’s intraspecific competition index we observed that higher competition induces lower mean growth and higher sensitivity to water balance, regardless of the number of thinning stages. Second, we selected an extreme drought event at each site and computed resistance and resilience indices, as well as the probability of tree mortality associated with the event. Within the single-stage thinning treatments, those with the highest intensity showed the highest resistance (i.e. the lowest growth decrease during the drought event), while stand density did not affect their resilience (i.e. growth recovery after the drought event). The effect of thinning intensity on the probability of death due to the drought event was not conclusive. On the other hand, the two-stage treatments presented much higher resistance and resilience values than the other treatments, suggesting that this modality of treatment could be effective in improving the adaptability of E. grandis to extreme drought events. We conclude that high-intensity thinning interventions could increase the ability of this species to cope with climate change and benefit solid wood production, where the associated decrease in stand-level growth may be compensated by an increase in the individual-tree growth. For other industrial purposes, where final stand-level production is a key driver, medium intensity two-stage thinning is recommended, in particular when genetic materials selected for drought resistance are not available and there is high climatic risk.

CaRPE: the Carbon Reduction Potential Evaluation tool for building climate mitigation scenarios on US agricultural lands

The Carbon Reduction Potential Evaluation (CaRPE) tool is a web-based interactive tool that integrates two databases for the USA collected at county/multi-county scales to visualize and estimate the climate benefits of implementing a variety of conservation practices on croplands and grazing lands. The COMET-Planner tool provides county/multi-county carbon sequestration and greenhouse gas emission reduction coefficients associated with the adoption of climate-smart agricultural management practices. The CaRPE tool couples these coefficients, reported in tonnes of carbon dioxide equivalents (CO2e) per acre per year, with county-level cropland and grazing land acres extracted from the US Agricultural Census. The CaRPE graphical user interface allows users to quickly and easily build and export scenarios of new conservation practice adoption on desired acreages and locations at state, regional or national scales. Results are in tonnes CO2e per year, and each scenario can be exported in tabular and map formats at the selected scales. Existing county-level cropland acreage data provide the upper boundaries for acres of adoption and can be modified based on specific goals established by the user.The output may be used to develop potential targets of adoption and help inform decisions related to resource prioritization and planning efforts. In collaboration with local experts and farmer-led organizations, the results can provide a key starting block to prioritize practices and areas that contribute to climate benefits. As the underlying databases and models are updated and improved, CaRPE can be revised accordingly to increase accuracy and enhance applicability. The CaRPE tool and the user guide are available at: Database URL: https://carpe.shinyapps.io/CarpeTool/.

An Object- and Shapelet-Based Method for Mapping Planted Forest Dynamics from Landsat Time Series

Large-scale afforestation in arid and semi-arid areas with fragile ecosystems for the purpose of restoring degradation and mitigating climate change has raised issues of decreased groundwater recharge and ambiguous climatic benefits. An accurate planted forest mapping method is necessary to explore the impacts of afforestation expansion on fragile ecosystems. However, distinguishing planted forests from natural forests using remote sensing technology is not a trivial task due to their strong spectral similarities, even when assisted by phenological variables. In this study, we developed an object- and shapelet-based (OASB) method for mapping the planted forests of the Ningxia Hui Autonomous Region (NHAR), China in 2020 and for tracing the planting years between 1991 and 2020. The novel method consists of two components: (1) a simple non-iterative clustering to yield homogenous objects for building an improved time series; (2) a shapelet-based classification to distinguish the planted forests from the natural forests and to estimate the planting year, by detecting the temporal characteristics representing the planting activities. The created map accurately depicted the planted forests of the NHAR in 2020, with an overall accuracy of 87.3% (Kappa = 0.82). The area of the planted forest was counted as 0.56 million ha, accounting for 67% of the total forest area. Additionally, the planting year calendar (RMSE = 2.46 years) illustrated that the establishment of the planted forests matched the implemented ecological restoration initiatives over the past decades. Overall, the OASB has great potential for mapping the planted forests in the NHAR or other arid and semi-arid regions, and the map products derived from this method are conducive to evaluating forestry eco-engineering projects and facilitating the sustainable development of forest ecosystems.

Disentangling the mechanism of temperature and water vapor modulation on ozone under a warming climate

Temperature and water vapor have been considered as important factors affecting ozone concentrations, however, their synergistic effect on ozone, as well as its response to a warming climate remains unclear. Here, numerical experiments with different combinations of climate and emissions highlighted opposite changes of annual ozone over the contiguous U.S. under scenarios with high vs. low ozone precursor emissions in the future with warming. Comparing the occurrence of heat waves on higher vs. lower ozone days, we found significant suppression of the heat wave exacerbation of ozone by anthropogenic emissions reductions. Variations of ozone with temperature (T) and water vapor (Q) over the western U.S. and southeastern U.S. in the simulations are clearly revealed through the construction of an O3-T-Q diagram. Based on the diagram, we further identified a T-dominant regime at higher temperatures where ozone increases with temperature increase, and a Q-dominant regime at lower temperatures where ozone decreases with temperature increase due to the negative effect of water vapor. With larger anthropogenic emission reductions, ozone may increase at a lower rate with temperature in the T-dominant regime, or even decrease with temperature in the Q-dominant regime. Our results show that with large emission reductions, substantial ozone pollution due to warming and increasing heat waves may be counteracted by water vapor, partly turning the ‘climate penalty’ on ozone into ‘climate benefit’. Hence controlling anthropogenic emissions may be an increasingly important strategy in a warmer and wetter climate to improve air quality and public health.

Is hydrogen production through natural gas pyrolysis compatible with ambitious climate targets in the United States? A location-specific, time-resolved analysis

Pyrolysis of natural gas to produce H2 and solid carbon through methane cracking can be characterized as a high-CH4, low-CO2 process. It results in low CO2 emissions because no direct CO2 is generated at the point of H2 generation if solid carbon is not combusted further. However, it results in high CH4 emissions because of its higher natural gas consumption compared to the direct use of natural gas and, thus, higher CH4 losses along the natural gas supply chain. Here, I analyzed whether this process can provide climate benefit in comparison to the direct, unabated utilization of natural gas and also in comparison with H2 produced from water electrolysis with grid electricity. To this end, Monte Carlo simulations of time-resolved and US state-specific emission profiles and their impact on mid-century global warming under different CH4 mitigation scenarios were conducted. It was found that the climate benefit of natural gas pyrolysis is highly dependent on plant location and the speed at which CH4 emissions can be abated. New York, Pennsylvania, and Ohio emerged as the most promising locations. This is because of their projected long reliance on natural gas for power generation, which renders electrolysis using grid electricity less attractive, as well as the relatively low estimate of current CH4 emissions from the natural gas supply chain. However, without fast action on CH4 emission mitigation, the climate benefit of natural gas pyrolysis is small or non-existent, irrespective of the plant location. Overall, the uncertainty in the relative climate benefit of natural gas pyrolysis was found to be large; however, this study developed an easy-to-adapt MS Excel/visual basic for applications (VBA) tool that can be updated as soon as more accurate data on CH4 emissions becomes available. Policymakers, businesspeople, and scholars can use this tool to estimate the climate impact within their own scenarios and locations.

Using crowdsourced data to estimate the carbon footprints of global cities

• A hybrid method is established to estimate the carbon footprints of global cities. • The method integrates top-down input–output analysis and bottom-up crowdsourced data. • Carbon footprints of 465 global cities in 2020 are estimated. • 10% of the global population in these cities account for 18% of global CO 2 emissions. • Unproportionable benefits could be obtained by carbon abatement in a few cities. Cities are at the forefront of the battle against climate change. However, intercity comparisons and responsibility allocations among cities are hindered because cost- and time-effective methods to calculate the carbon footprints of global cities have yet to be developed. Here, we establish a hybrid method integrating top-down input–output analysis and bottom-up crowdsourced data to estimate the carbon footprints of global cities. Using city purchasing power as the main predictor of the carbon footprint, we estimate the carbon footprints of 465 global cities in 2020. Those cities comprise 10% of the global population but account for 18% of the global carbon emissions showing a significant concentration of carbon emissions. The Gini coefficients are applied to show that global carbon inequality is less than income inequality. In addition, the increased carbon emissions that come from high consumption lifestyles offset the carbon reduction by efficiency gains that could result from compact city design and large city scale. Large climate benefits could be obtained by achieving a low-carbon transition in a small number of global cities, emphasizing the need for leadership from globally important urban centres.

Opportunities beyond CO2 for climate mitigation

Opportunities beyond CO2 for climate mitigation

From inclusive climate to organizational innovation: Examining internal and external enablers for knowledge management capacity.

As the diversity field evolves, scholars are shifting the attention from mitigating "problems" associated with diversity to searching for ways to leverage the potential value in diversity. We advance this field by studying how an inclusive climate benefits organizational innovation, an important foundation for sustained competitive advantage. Adopting a synergy perspective, we examine the internal (i.e., workplace demographic diversity in terms of age, gender, and region) and external contingencies (i.e., environmental scanning and environmental uncertainty) for an inclusive climate to foster incremental and radical innovation through the mechanism of knowledge management capacity. We tested our research model with a three-wave data collection from multiple sources (i.e., employees, human resource managers, and executives) in 102 organizations. We found that workplace age and regional diversity (but not gender diversity) strengthened the positive effect of inclusive climate on knowledge management capacity, and subsequently incremental and radical innovation. The facilitating effect of environmental scanning was only significant for organizations that experienced higher environmental uncertainty. Our research highlights the importance of considering the synergistic potential of internal human resources and external environments for organizations to capitalize on their inclusive climate for knowledge management and innovation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).