Solar parks are a rapidly expanding novel land use primarily to produce renewable energy. However, the aim is to make them multifunctional, and limit negative impacts on soils or even improve soil quality. Solar panels change the microclimate and cause shading below the panels, influencing plant growth and carbon and water inputs to the soil, with potential cascading effects on the soil biota. This research aimed to test the effect of solar panels on earthworm and nematode communities in 12 solar parks with contrasting designs across the Netherlands. Earthworm abundance and diversity, plant biomass and nematode abundance were measured between (gap) and below the solar panels. Nematode abundance was also measured at the highest and lowest edges of the panels. Plant biomass, nematode abundance and earthworm abundance were all significantly lower below the solar panels compared to in the gap between the panels. Nematode abundance at the highest and lowest edges showed intermediate numbers compared to the gap and below the panels. These results show that solar parks have a large impact on the soil biota and stress the need for guidelines for ecologically sound solar park designs to prevent soil damage.

How to cite: Scholten, L., De Deyn, G., and de Goede, R.: Solar park impacts on plant biomass and earthworm and nematode communities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1833, https://doi.org/10.5194/egusphere-egu24-1833, 2024.

Solar energy is the most rapidly growing renewable globally. However, ground-mounted solar panels have a high land requirement, leading to extensive, low-nature-value photovoltaic parks. This may be alleviated by considering ecological aspects during their planning, construction and mainetnance. The resulting ecovoltaic park can bring various benefits for the owners if ecosystem services related to the imporved ecological conditions are recognized and wisely utilized. A major step in developing ecovoltaic parks is the creation of a short but species-rich grassland ecosystem. There is little empirical evidence on how to achieve this; therefore, we set up an experimental sowing experiment in three formerly conventional photovoltaic parks located in the forest-steppe zone of Hungary. From the regional native grassland species pool, we selected short but competitive ones (two graminoids and 50 forbs that are often visited by pollinators), and sowed them in half of the parks (between panel rows) in October, 2022, while the other half was left as control. In 2023, we surveyed the vegetation of the sown and control parts of the parks and adjacent old-growth grasslands (as references), and found that total plant species richness and the species richness of grassland specialists increased compared to the control sites, but remained below the references. In contrast, the cumulative cover of grassland specialist species in the sown sites could reach the references. We also surveyed pollinator assemblages (hoverflies and wild bees), and found higher species richness and Shannon diversity in the sown parts then in the reference grasslands, while control parts of the parks showed intermediate values. This might have been caused by spillover from the sown parts, although flying pollinators might have also taken advantage of the permanent windshade among the panel rows of control parts, despite the low food supply compared to the reference grasslands. Our findings suggest a rapid improvement of plant and pollinator assemblages after sowing native seed mixtures in solar parks. The resulting high-nature-value grassland ecosystem can have many co-benefits for the owners, as (i) it requires lower management intensity due to the short vegetation, (ii) has the potential to offer high-quality forage for livestock or honey-bees, and (iii) lowers the widespread “not-in-my-backyard” syndrome of local inhabitants due to its attractive, flower-rich appearance.

How to cite: Tölgyesi, C., Magyar, B., Frei, K., Hábenczyus, A. A., Bátori, Z., and Gallé, R.: Introducing the first ecovoltaic parks of Hungary: a reconciliation between solar development and nature conservation, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2933, https://doi.org/10.5194/egusphere-egu24-2933, 2024.

In Taiwan's rural areas, significant changes are underway in the once-predominant focus on traditional agriculture. The current landscape in rural areas is characterized not only by the presence of numerous factories but also by the increasing solar panels, driven by the ongoing transition to renewable energy sources. Despite numerous studies confirming the correlation between land use and temperature in urban areas, limited thermal research has been conducted in rural regions. Additionally, rural residents, particularly the elderly, are more sensitive to temperature variations.

The purpose of this study is to investigate whether the construction of iron rooftop factories and rooftop solar panel structures in rural environments results in significant differences in surface temperature and surrounding land use, thereby revealing the thermal impacts of these structures.Three coastal towns in central Taiwan were selected as the primary study area due to their higher density of solar panels and similar agricultural characteristics. Landsat 8 surface temperature data were utilized, with buffer zones established at 30-meter intervals from sample boundaries to explore variations in surface temperature and land use characteristics.

The findings reveal that rooftop solar panels and iron factories are predominantly surrounded by arid fields. As the distance from rooftop solar panels increases, the surface temperature gradually decreases, returning to ambient levels. However, no discernible changes in surface temperature were observed around iron rooftop factories. This study not only sheds light on the thermal impacts of these structures in rural environments but also points out the importance of land use control on thermal environments.

How to cite: Lee, Y.-J., Chung, M.-K., and Tseng, W.-L.: Coexisting Agriculture, Industry, and Energy in Rural Areas： Comparative Surrounding Surface Temperatures between Rooftop Solar Panels and Iron Rooftop in the Yunlin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13845, https://doi.org/10.5194/egusphere-egu24-13845, 2024.

Against the backdrop of the rapid global rise of solar photovoltaic (PV) energy, its supply chain from manufacturing to installation has gradually exhibited dynamic spatial evolution, yet the spatiotemporal distribution of greenhouse gas emissions and mitigation throughout the entire PV industry chain has not received sufficient attention. The pathways to enhance the net mitigation benefits of PV through international collaboration across the entire industrial chain remains in its initial stage. This presentation will outline the author's systematic accounting of global supply chain carbon emissions and mitigation, combining spatiotemporal dynamic lifecycle assessments and scenario analyses. The analysis explored the spatiotemporal evolution of net greenhouse gas mitigation from 2009 to 2060 within the global PV industry. The study reveals that optimized collaboration between manufacturing and installation globally could increase the net mitigation effects of the entire industrial chain by 97.5 Gt carbon dioxide equivalent, equivalent to 1.9 times the global GHG emissions in 2020. This finding provides theoretical and empirical support for enhancing international strategic cooperation to enhance global greenhouse gas mitigation.

How to cite: Chen, S. and Lu, X.:  Greenhouse gas emissions and mitigation in the global solar photovoltaic industry chain, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13733, https://doi.org/10.5194/egusphere-egu24-13733, 2024.

The transition towards a decarbonized electricity system, based on renewable energies, is urgently needed to achieve the so-called carbon neutrality and help mitigating climate change, among other reasons. At the same time, there is a need for electricity production from renewable energies to be stable in time, or to follow the demand, without substantial fluctuations. The open-access step-wise model called CLIMAX exploits the fact that wind and solar photovoltaic (PV) power present a certain degree of spatio-temporal complementarity in order to reduce the volatility of their combined production at its minimum. In a previous study, CLIMAX was used to identify optimum deployments of PV and wind power facilities across five European domains (Jerez et al., 2023). Here, using these optimum capacity density scenarios, the installed capacity per European country for the period 2012-2020 as reported in IRENA (2020), and ERA5 reanalysis data for the same period, are used to compute capacity factors, and the wind-plus-solar electricity production is estimated and compared to that from a BASE scenario with a homogeneous spatial distribution of installations. Results show that the optimization of the spatial distribution of the wind-plus-solar installed capacities does not only enhance the stability of the energy production in time, but also in terms of mean values (i.e. efficiency). More precisely, an average improvement in the energy production of +47.5 TW·h per year, integrated over Europe, is obtained as compared to BASE. Consequently, pollutant emissions from thermal power plants could have been reduced if electricity would have been produced from these renewable sources. In this work, this reduction is estimated and, in a last step, the potential reduction of human deaths related to air pollution is also evaluated. Results encourage further efforts towards a low-carbon energy future.

REFERENCES:

Jerez, S., Barriopedro, D., García-López, A., Lorente-Plazas, R., Somoza, A. M., Turco, M., et al. (2023). An action-oriented approach to make the most of the wind and solar power complementarity. Earth's Future, 11, e2022EF003332. https://doi.org/10.1029/2022EF003332.

IRENA. (2020). Renewable capacity statistics 2020. International Renewable Energy Agency (IRENA).

How to cite: Gallardo, V., Jiménez-Guerrero, P., and Jerez, S.: Optimized renewable energy production for a low-carbon future to mitigate climate change and associated health impacts, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22105, https://doi.org/10.5194/egusphere-egu24-22105, 2024.

In recent years, there has been an increased interest in technologies such as Vortex-induced vibration energy harvesters (VIV-EH) concerning the potential to harvest and utilise the energy potential in oceans, rivers, channels and water pipelines. VIV-EH could be an ideal solution for energy generation through harvesting the kinetic energy from flow-induced vibration in open water systems such as rivers, lakes and lagoons, as well as closed water systems like water pipe systems in water and energy infrastructure. The energy generated could enable a self-powered sensor monitoring system and, therefore, replace the need for batteries or diesel generators to power the monitoring system, enhancing the water system's reliability. One of the applications explored for deploying VIV-EHs is installing into existing water pipelines to harness the flow vibration for energy generation. Assessing the feasibility of new energy technology such as VIV-EH is crucial to successfully implementing any technology into the pre-existing system. To fully determine feasibility requires information and inputs attained from assessing multiple cross-dimensional factors, which can provide information on the positive and negative economic, environmental and societal impacts and technological barriers or opportunities related to implementing this technology to any existing system infrastructure. To address this, an assessment framework is being developed, incorporating data and calculations from Life Cycle Assessment for calculating environmental impacts, MatLab for calculating the VIV-EHs key characteristics, and stakeholder engagement for assessing the selection of crucial evaluation metrics. The assessment tool will allow the user to carry out a multi-dimensional (Socio-Economic, Technical, Environmental) or single-dimension feasibility assessment concerning the integration of VIV-EHs into existing water infrastructure using a web-based tool. The application of the assessment framework provides critical informations such as VIV-EH's energy generation potential and role in the energy transition towards a cleaner and green energy system, which are relevant to designing a technology implementation strategy. The framework is applied, tested and used to evaluate the potential of VIV-EHs in various case studies: i) a geothermal district heating network in Reykjavik, Iceland; ii) a drinking water supply system in Ferlach, Austria, and iii) the MOSE flood protection in the Lagoon of Venice, Italy. Preliminary results suggest that the VIV-EH can reach capacities to supply sufficient energy – measured in watts – to power sensors for monitoring, maintenance and operation of water infrastructure. This continuous supply for monitoring networks can increase the resilience of water infrastructure and improve water resource utilisation, which is becoming more critical during climate change. The findings will be used to develop the assessment tool further and provide information that can help build a strategy for deploying VIV-EHs into water and energy infrastructure across Europe. The framework is tested on representative case studies across Europe but can potentially be applied in any energy system worldwide.

How to cite: Guðlaugsson, B., Secnik, M., Stepanovic, I., Bronkema, B., Hocevar, M., and Finger, D.: Multi-Dimensional Feasibility Assessment of the Deployment of Vortex-induced vibration Energy Harvester to utilize hidden hydro potential in European water and energy infrastructure, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10664, https://doi.org/10.5194/egusphere-egu24-10664, 2024.

Abstract

Energy storage systems (ESS) are required to overcome the challenges of large-scale integration of variable renewable energy. Specifically, offshore ESS can increase the utilisation of offshore transmission cables and reduce stress on the grid. Marine pumped hydro storage (PHS) is a promising technology in this domain [1]. This study focuses on the role of a subsea PHS system in offshore wind farms, taking the Dutch North Sea as a case study. This novel technology stores electricity on the seabed by pumping water to a reservoir subject to the hydrostatic pressure of the overlying seawater, and releases it by letting the water flow back through a set of turbines to a second reservoir at atmospheric pressure, thus utilising the change in potential energy associated with pressure difference.

Anthropogenic activities increasingly deploy marine environments as sites of operation. Besides traditional uses like fisheries, navigation, defence and
mining, the climate and biodiversity crises respectively call for the uptake of offshore renewable energy systems and biodiversity-enhancing structures such as artificial reefs. These activities affect the marine host ecosystems, though impacts can be both beneficial (providing artificial habitats) and detrimental (disturbing species) [2].

The European Topic Centre on Inland, Coastal and Marine waters highlights the importance of marine spatial planning and environmental impact assessment (EIA) methods in elucidating conflicts of interest between the development of offshore renewable energy and protection of the marine environment [3]. Though the environmental impacts of offshore renewable energy projects such as wind and even wave farms have been investigated and are safeguarded by EIA legislation, only few studies can be found on offshore energy storage. Research on offshore ESS mainly focuses on either the (life-cycle) environmental impacts of a technology, or on the technical and/or economic performance in terms of efficiency, feasibility or costs and benefits. The combination is lacking for specific technologies and areas, such as subsea PHS. Therefore, this study integrates a techno-economic modelling approach with EIA methodology with the objective of obtaining the techno-environmental potential of subsea PHS as a novel offshore energy storage system.

First, a literature review is conducted to compose a framework for the assessment of biological, chemical and physical impacts of offshore energy storage systems, consisting of a list of impact indicators and, if available, threshold values. Second, the framework is applied to a case study of subsea PHS in the Dutch North Sea. The technical potential, i.e., the optimal installed capacity from a technical point of view, is determined by modelling the Dutch planned offshore wind farms until 2030, allowing for installation of the storage technology to minimise curtailment of wind energy in the system. The model is formulated as a mixed-integer linear program. Third, the impact indicators are investigated for the resulting technology size and, taking threshold values into account, the environmental potential is determined. Last, trade-offs between technical performance and ecological effects are identified and discussed.

References

[1] Wang et al. A review of marine renewable energy storage. International Journal of Energy Research, 2019.
[2] Taormina et al. A review of methods and indicators used to evaluate the ecological modifications generated by artificial structures on marine ecosystems. Journal of Environmental Management, 2022.
[3] Galparsoro et al. Mapping potential environmental impacts of offshore renewable energy. European Topic Centre on Inland, Coastal and Marine waters, 2022.

How to cite: Ossentjuk, I., Wiegner, J., Nienhuis, R., Griffioen, J., Vakis, A., and Gazzani, M.: The techno-environmental potential of offshore pumped hydro storage: A case study of the Dutch North Sea, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12276, https://doi.org/10.5194/egusphere-egu24-12276, 2024.

Worldwide changes in the land use and climate are the main drivers that have triggered a decline in both biological and cultural diversities, and the degradation of ecosystems. In countries like Brazil, deforestation is the main source of greenhouse gas emissions, and it is increased, in some cases, by the degradation. As response to those challenges, degraded areas have emerged as a promising option for cultivating biomass to produce biorenewables, aligning with the concept of a 'green transition'. Brazil stands out as a viable region for new cropland requirement to address the global demand for biorenewables production. Nevertheless, despite the large areas of degraded pastureland in Brazil, identifying those for growing the crops avoiding worsening the principal causes of biodiversity loss is an issue to be addressed. We evaluated the ecological feasibility of degraded pasturelands as potential areas for biomass production. We selected four exclusion criteria based on the Brazilian legal framework and the conventions and agreements to which the country is a signatory. In 2021, Brazil had 98.1 Mha of degraded pasturelands with the largest portion (63.9 Mha) experiencing a moderate level of degradation, mostly in Amazon biome (22.3 Mha). In addition, Brazilian legislation for biofuels production (Renovabio) predicts the exclusion of Amazon and Pantanal (a Brazilian wetland) biomes as eligible areas. Those biomes were the first exclusion criteria, remaining 65.1 Mha after its exclusion. In terms of protected areas, another adopted criterion, the land of traditional populations evaluated contains fewer degraded areas (0.3 Mha), when compared to the other Brazilian conservation categories (1.2 Mha). In the excluded degraded pasturelands (55.8 Mha, in total), the restoration of native vegetation should be prioritized to enhance biodiversity loss and the mitigation of climate change. Restoration efforts may vary by region, but agroforestry systems using native species of the biome could be a positive alternative. In addition to prioritizing the recovery of habitat and biodiversity loss, this approach has the potential to decrease local social vulnerabilities and to promote sustainable biorenewables production. By prioritizing the conservation of biological diversity, Brazil still has 42.3 Mha available for biorenewables, which corresponds to almost the total area currently under soybean cultivation in the country. The greater availability of degraded pastureland areas is within the Brazilian savanna. In addition to be a biodiversity hotspot, the Brazilian savanna is also central to water supply, contributing to important river basins in the country. Future work should consider other criteria such as water scarcity and climate vulnerability since it is necessary to evaluate the whole biorenewables’ value chains to assure sustainability.

How to cite: Padgurschi, M., de Souza Henzler, D., Palma Petrielli, G., and A. D. Hernandes, T.: Degraded pasturelands for sustainable biorenewables production: an ecological approach, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-22175, https://doi.org/10.5194/egusphere-egu24-22175, 2024.

China and India, two of the world's leading carbon emitters, have pledged to achieve carbon neutrality by mid-century in alignment with the Paris Agreement. Central to this ambition is the electrification of their economies, and both nations have made significant strides in recent years. Yet, a thorough cost-benefit analysis of their energy transition progress and future energy transition pathways remains lacking. Here we adopt nine comprehensive models to assess the region-specific co-benefits related to carbon emission, air pollution, health and employment of energy transition in the power sector in China and India from 2015-2020 and further explore their most cost-effective pathways towards 1.5°C and 2°C scenarios in 2030-2050. We find that although the emissions contributed by the power sector in China and India from 2015 to 2020 resulted in more than 10,000 PM_2.5 attributable deaths in 2020, the economic benefit of job creation of new installation of renewable power in 2020 was 68 (95% CI: 56-93) times and 6 (95% CI: 5-7) times than the monetary of health loss. Under the SSP1_RCP2.6 scenario, it will ultimately achieve the largest benefit (monetary health co-benefits) to cost (carbon mitigation cost) ratio for both countries in 2050, and India (14.6 (95% CI: 12.7-16.1) will obtain a larger ratio than that of China (4.1 (95% CI: 3.3-4.7)). We recommend both nations deepen their commitment to power sector transition, prioritizing low-carbon fuels and expanding education and skill training to support the emerging new energy economy.

How to cite: Lu, C.: Co-benefits and cost-benefit analysis of energy transition in the power sector in China and India, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20459, https://doi.org/10.5194/egusphere-egu24-20459, 2024.

African tropical ecosystems possess great potential for nature-based solutions in mitigating fossil fuel emissions through absorbing and storing carbon in soil and vegetation. However, past studies mostly focused on pan-continental carbon balance quantification, often ignoring regional differences. Remarkably, few science-informed attempts have been made to refine carbon flux estimates at the national level within African rainforest countries. Yet, such refined estimates are essential to improve the quantification of Nationally Determined Contributions for the United Nations Framework Convention on Climate Change.

In this contribution, we present preliminary results on quantifying national carbon budgets for African rainforest countries by disentangling three major carbon fluxes for the period 2001-2015: (1) net carbon uptake in tropical savannas, woodlands, and forests, (2) carbon losses from land-use change, and (3) fossil fuel emissions. Carbon fluxes in intact forests are quantified using ground-based data¹, while the carbon uptake by intact savannas and woodlands is based on Net Primary Productivity assessments estimated from remote sensing products^2,3. Furthermore, carbon emissions from land-use change are estimated by analyzing various satellite images and related products providing data on land-use change^4–6, soil and tree carbon stocks^7–12, fire emissions^3,13,14, and carbon recovery in regrowing forests^15–18 in tropical Africa. Country-level fossil fuel emissions are taken from the Global Carbon Project database¹⁹ to complete the national carbon balances.

We reveal that most Central and East African rainforest countries acted as net carbon sinks between 2001 and 2015, while West African rainforest countries exhibited minimal net carbon loss. Overall, tropical ecosystems have played an important role in mitigating carbon emissions due to land-use change and fossil fuels in African rainforest countries, particularly in Congo Basin countries. Our insights into nation-level carbon fluxes will be crucial for informing African rainforest countries, guiding climate policies to stay on track to keep global warming well below 2°C.

References:

1. Hubau, W. et al. Nature 579, 80–87 (2020).
2. Running, S.W. et al. BioScience 54, 547-560 (2004).
3. Randerson, J.T. et al. (2018).
4. Hansen, M.C. et al. Science (1979) 342, 846–850 (2013).
5. Vancutsem, C. et al. Sci Adv 7, eabe1603 (2021).
6. Curtis, P.G. et al. Science (1979) 361, 1108–1111 (2018).
7. Simard, M. et al. Nat Geosci 12, 40–45 (2019).
8. Avitabile, V. et al. Glob Chang Biol 22, 1406–1420 (2016).
9. Zarin, D.J. et al. Glob Chang Biol 22, 1336–1347 (2016).
10. Saatchi, S.S. et al. Proc Natl Acad Sci USA 108, 9899–9904 (2011).
11. Baccini, A. et al. Nat Clim Chang 2, 182–185 (2012).
12. Poggio, L. et al. SOIL 7, 217–240 (2021).
13. Van Wees, D. et al. Geosci Model Dev 15, 8411–8437 (2022).
14. Di Giuseppe, F. et al. Atmos Chem Phys 18, 5359–5370 (2018).
15. Heinrich, V.H.A. et al. Nature 615, 436–442 (2023).
16. Deklerck, V. et al. Biol Conserv 233, 118–130 (2019).
17. Cook-Patton, S.C. et al. Nature 585, 545–550 (2020).
18. IPCC. 6 (2006).
19. Friedlingstein, P. et al. 14, 4811–4900 (2022).

How to cite: Verbiest, W. W., Ewango, C. E., Makana, J.-R., Lewis, S., Bauters, M., Bastin, J.-F., Fayolle, A., Gorel, A.-P., and Hubau, W.: Disentangling national carbon fluxes of African rainforest countries., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9583, https://doi.org/10.5194/egusphere-egu24-9583, 2024.

Soil organic carbon dynamics are strongly influenced by soil and climate conditions, as well as management practices including grazing and cropping. Over the past two decades, biogeochemical models have been widely used for analysing the effect of different environmental and management variables on soil carbon, including potential change under hypothetical future climate and management scenarios. The DayCent model, which is a daily implementation of the Century model, considers the impacts of soil texture, climate, historical vegetation cover, and land management practices, including crop type, fertilizer additions, and cultivation events on soil carbon dynamics.

In this study, we calibrate the DayCent model for two long-term (38-year) native pasture exclosures at one location in south-eastern Queensland. These sites have had similar management, being ungrazed and burnt or mown at the beginning of each pasture growing season but differ with respect to soil type (texture and depth) and species composition. One site is dominated by kangaroo grass (Themeda triandra), which represents the species composition prior to the introduction of tree clearing and grazing by cattle in the late 1800s. The other site is dominated by black spear grass (Heteropogon contortus) which has become the dominant species in the region since that time. To reflect the long-term species composition changes in the region, kangaroo grass crop parameters were used to run the model to equilibrium from year 1 AD to the year 1900 for both sites, and spear grass parameters were introduced in 1901 for the spear grass site.

The model calibration concentrated on the key ‘crop’ parameters governing potential production, root to shoot ratio, and plant carbon to nitrogen ratio. The calibrated DayCent model accounted for only 21 percent of the observed year-to-year variability in end-of-season above-ground biomass at the kangaroo grass site and 58%  at the spear grass site. The observed biomass production for the two sites was most strongly correlated with simulated evapotranspiration during the growing season (R² = 0.43 and 0.58 for kangaroo grass and spear grass respectively) and we found a strong correlation between simulated and observed soil water content to a depth of 50 cm at both sites (R² = 0.64 and 0.6 for kangaroo grass and speargrass respectively).

Whilst year-to-year variability was not well simulated, the long-term average production of each site is the main driver of soil carbon. For both sites, the model overestimated the average observed above-ground biomass at the end of the growing season by approximately 15 percent. By this time of year, the plants have flowered and lost biomass through the detachment of seeds and seed heads as well as some dead leaves. The timing of this detachment process is difficult to simulate in DayCent and it is therefore likely that DayCent simulated the annual biomass production quite closely. It remains to validate the DayCent simulations against similar long-term production data at a further six long-term study sites at this location and to evaluate how well DayCent simulates observed soil carbon across soil types, both under grazed and ungrazed conditions.

How to cite: Mirsafi, Z., Day, K., Parton, W., Takeda, N., and Rowlings, D.: Calibration of the DayCent Model for Native Pastures in South-Eastern Queensland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13162, https://doi.org/10.5194/egusphere-egu24-13162, 2024.

Highly accurate land cover (LC) information with fine spatial resolution serves as the cornerstone for reliable environmental insights, strategic land management, and ecological conservation. Yet, existing public LC products with 1-30m resolution exhibit considerable inconsistencies, particularly within complex terrains and fragmented habitats such as hill and gully regions, leading to uncertainties in various applications. In this context, our study innovatively targeted China's hilly and gully regions to develop an enhanced 10m resolution LC map for 2020, termed CLC-HG. The methodological advancement lied in fusing multiple LC products through accuracy evaluation, spatial consistency verification, object-oriented classification, and random forest classification. The research involved: (1) Strategic zoning of hilly and gully regions into five areas, selecting one or two representative validation regions within each; (2) Leveraging high-resolution imagery and 20000 field verification points to derive a 1m resolution land use dataset for validation regions, named GFLUCC, with 1m resolution and 95% accuracy; (3) Comprehensive validation of seven land use products spatial consistency and accuracy based on GFLUCC; (4) Filtering of layers based on spatial consistency, retaining regions with high and medium consistency; (5) Utilizing object-oriented classification and random forest classification, a higher-accuracy LC dataset was generated to replace the layers that were removed in the spatial consistency process; (6) Successful creation of CLC-HG, mirroring the accurate land use patterns of 2020. Our findings elucidated: (i) The superiority of WorldCover 10m in LC classification, contrasting with other products' regional inaccuracies; (ii) The influences of terrain complexity and human activity on accuracy, highlighting the precision in uniform areas versus the inaccuracy in complex regions; (iii) Substantial variations in spatial consistency across different terrains, with LP showing the weakest consistency; (iv) CLC-HG's remarkable performanced in identifying diverse LC types, boasting 85% overall accuracy; (v) Notable progress in classification accuracy with CLC-HG, uncovering the nuanced influences of land category complexity on consistency and human interventions on accuracy. This study breaks new ground by integrating multidimensional data and methodologies, contributing valuable insights for classification enhancements and more adept land resource management. The pioneering CLC-HGproduct holds significant potential to reduce uncertainties in global environmental change studies, ecosystem evaluations, and hazard assessments, marking an important step forward in remote sensing applications.

How to cite: Chen, L.: Multisource fusion for high-accuracy land cover mapping: A 10m resolution strategy in China's hill and gully regions , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9379, https://doi.org/10.5194/egusphere-egu24-9379, 2024.

The urban population is experiencing rapid growth, and it is estimated that around 90% of people will be living in cities by the year 2100. Given that urban areas are significant sources of greenhouse gas and pollutant emissions, and with the expectation that these urban areas will become even more densely populated, achieving sustainable urban living requires careful and well-informed urban planning for infrastructures capable of effectively mitigating these emissions. One commonly proposed approach to address this challenge is the implementation of urban green infrastructures, which are often regarded as net sinks for CO₂. However, due to the diverse and varied land use within urban areas, our ability to precisely isolate and quantify their overall impact on the city's carbon balance is limited.

Our research aims to overcome this limitation by testing two distinct frameworks. The first integrates remote observations with local measurements to determine the carbon balance of green infrastructures at the city level, ultimately producing a detailed CO₂ sequestration map of these infrastructures. The second utilizes satellite observations of solar-induced chlorophyll fluorescence, a signal emitted exclusively by vegetation, to estimate urban vegetation's city-wide carbon sequestration potential. Our findings demonstrate that these two frameworks provide valuable insights into the carbon sequestration capacity of green infrastructures.

The frameworks developed in this study offer a significant advancement in understanding the contribution of green infrastructures to the carbon budget of cities. This improved understanding can inform the planning of low carbon-emitting cities and aid in identifying green areas with limited—or even negative—net carbon uptake. Additionally, the results of this research may be instrumental for policymakers and city planners in developing more sustainable urban environments.

How to cite: Kira, O., Bamah, J., Muleta, A., and Bushner, S.: Remote sensing-based frameworks to quantify city-level carbon fluxes in urban green infrastructures, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4551, https://doi.org/10.5194/egusphere-egu24-4551, 2024.

The quantification of carbon sequestration in Urban Green Spaces (UGSs) is challenging due to their unique characteristics such as the fragmentation of green spaces, human-influenced species selection, and varying management practices. IPCC guidelines recommend calculating carbon sequestration in UGSs per individual tree or crown cover area. Although crown cover area-based estimation is commonly used in national greenhouse gas inventories, research on the growth rate based on crown cover area (CRW) and the effects of varying sampling methodologies is limited. This research aimed to calculate CRW [ton C (ha crown cover)^-1 yr^-1] in South Korea using two distinct sampling methods. Method_SS (M_SS; Systematic Sampling Method) divided urban areas into 500m x 500m grids and selected a 5% sample (1,603 grids) randomly. Within each grid, three sites were chosen and vegetation at three points was surveyed. For analysis, only points with trees excluding shrubs were included. Method_CS (M_CS; Categorized Sampling Method) divided UGSs into three categories: street trees, urban parks, and others. For each category, 48 sites with three plots each were selected. In the street trees category, a plot consisted of 20 trees, while in urban parks and others, a plot was defined as a 20 x 20 m area. At each plot, species, diameter at breast height (DBH), height, and crown width of all trees were measured. For the derivation of CRW, a total of 8,037 and 5,733 trees were used in M_SS and M_CS, respectively. CRW was calculated in four steps: 1) The carbon storage of individual trees (C_t1) was calculated using allometric equations and the carbon fraction. 2) The carbon storage from one year prior (C_t2) was estimated based on the annual DBH growth rate (cm yr^-1). 3) The annual carbon accumulation (kg C tree^-1 yr^-1) was calculated as the difference between C_t1 and C_t2. 4) CRW was calculated by dividing the total annual carbon accumulation by the total crown cover area of the surveyed trees. As a result, The study revealed a notable difference in CRW between M_SS and M_CS. M_SS reported CRW of 0.23 ton C ha^-1 yr^-1, while M_CS presented 0.30 ton C ha^-1 yr^-1. When categorized by land use, CRW was found to be highest in urban parks followed by others and street trees. In M_SS, the diverse sample locations resulted in a wider range of DBH values, including many large-sized trees (DBH ≥ 70 cm). The lower CRW estimates in M_SS were primarily due to the assumption that large-sized trees had zero annual carbon sequestration following the IPCC guidelines. This led to a higher inclusion of large-sized trees in M_SS, resulting in lower CRW values. Also, there were significant differences in species distribution, tree sizes (DBH), and CRW, depending on the sampling methodology. These variances are primarily due to the unique characteristics of UGSs. The study highlights the necessity for further research into more representative sampling methodologies for estimating carbon sequestration in UGSs.

How to cite: Lee, J., Jo, H., Kim, W., and Son, Y.: Annual Carbon Sequestration Per Crown Cover Area of Urban Green Spaces in  South Korea: Comparative Analysis Using Different Sampling Methodologies, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14214, https://doi.org/10.5194/egusphere-egu24-14214, 2024.

An increasing amount of CO₂ emissions from the household sector of Iran led us to analyze the inequality and understand the possible driving forces behind the CO₂ emissions. The household sector in Iran contributes one of the largest sectors of CO₂ emissions. The study of inequality provides information to policy‐makers to point policies in the right direction. By considering the differences in the socio‐economic factors of provinces, the study aims to analyze the inequality in CO₂ emissions and different kinds of energy consumption, including oil, gas and electricity, for the household sector of Iran’s provinces between 2000 and 2019. Also, Household panel data of 28 provinces of Iran are employed by using both static and dynamic panel models for the years 2001 to 2019. This study investigates the relationship between CO₂ emissions and the efficient factors in three major groups including energy, climate, and household socio-economic factors. the Theil index and Kaya factor, as a simple and common method, were considered to evaluate the inequality in both CO₂ emissions and energy consumption, and determine the driving factor behind CO₂ emissions. According to the results, inequality in oil and natural gas consumption were increasing, electricity was almost constant; however, CO₂ emissions experienced a decreasing trend for the study period. The results of the Kaya factor indicate that the second factor, energy efficiency, with a 0.21 value was the main driving factor of inequalities in CO₂ emissions. The empirical result of the static method showed a positive dependence of household CO₂ emissions on Heating Degree Days (HDD), Cooling Degree Days (CDD), precipitation level, oil consumption, gas consumption, household income, size of household, and also building stocks. Also, removing the energy subsidy for fossil fuels due to substantial subsidy in fossil fuels in Iran or implementing a re-pricing energy policy can be a beneficial way to control carbon emissions from households within the provinces of the country.

Behnam Ata is funded by the Stipendium Hungaricum scholarship under the joint executive program between Hungary and Iran.

The study was elaborated under the research project TKP2021‐NKTA‐32 . 

How to cite: Ata, B., Pakrooh, P., and Pénzes, J.: Inequality and driving factors in regional level energy-related CO2 emissions at a residential sector of Iran, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5653, https://doi.org/10.5194/egusphere-egu24-5653, 2024.