• Energy Research
• 2025-2025close

Tropical forests are of great ecological and climatological importance. Although they only cover about 6% of Earth’s surface, they are home to approx. 50% of the world’s animal and plant species. Their trees store 50% more carbon than trees outside the tropics. At the same time, they are one of the most endangered ecosystems on Earth: about 6 million of hectares per year are felled for timber or cleared for farming. Compared to the other components of the carbon cycle (i.e. the ocean as a sink and the burning of fossil fuels as a source), the uncertainties in the local land carbon stocks and the carbon fluxes are particularly large. This is especially true for tropical forests: more than 98% of the carbon flux generated by changes in land-use may be due to tropical deforestation, which converts carbon stored as biomass into emissions.In this context, the AfriSAR 2015/16 campaign, supported by ESA, was carried out over four forest sites in Gabon by ONERA (July 2015) during the dry season and by DLR (February 2016) during the wet season. From the data collected the innovative techniques applied to estimate forest height and biomass could be improved significantly and are summarized in a special issue ‘Forest Structure Estimation in Remote Sensing’ of IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.The motivation of the AfriSAR campaign was to acquire demonstration data for the soon to be launched ESA BIOMASS mission, that was selected as the 7th Earth Explorer mission in May 2013 in order to meet the pressing need for information on tropical carbon sinks and sources by providing estimates of forest height and biomass. AfriSAR focused on African tropical and savannah forest types (with biomass in the 100-300 t/ha range) and complements previous ESA campaigns over Indonesian and Amazonian forest types in 2004 (INDREX-II) and 2009 (TropiSAR).The present contribution concerns the GABONX campaign, the ESA supported successor to AfriSAR, which took place in May to July 2023. GABONX aims to detect and quantify changes that have occurred since the DLR acquisitions in February 2016. To this end, DLR’s F-SAR sensor acquired interferometric stacks of fully polarimetric L- and P-Band data over the same forest sites in the same flight geometry as in 2016. The results presented give an overview of campaign activities with particular emphasis on the calibration of the SAR instrument as well as the validation of forest parameters derived from polarimetric interferometry. The SAR sensor calibration is based on an innovative approach that leverages state-of-the-art EM simulation to accurately characterize the 5m trihedral reference target deployed for the campaign in Gabon. The validation of derived forest parameters uses lidar measurements obtained in the time frame of the GABONX campaign by NASA’s LVIS sensor. As an outlook, further collaborative calibration and validation activities will hopefully include the cross-calibration of DLR’s F-SAR and NASA’s UAVSAR, which is set to acquire L- and P-Band data over the GABONX sites in 2024.

Based on the findings of present investigation, it can be inferred that physico-chemical properties and microbial population in soil was also varied with land use whereas the physico-chemical properties and microbial population were generally improved in kharif as compared to rabi. Plantation land use was the best land use system followed by forest land use system for sustainable improvement of soil health may be recommended in the eastern region of Uttar Pradesh or similar agro ecoregions.

The climate crisis is the biggest threat to the health, development, and wellbeing of the current and future generations. While there is extensive evidence on the direct impacts of climate change on human livelihood, there is little evidence on how children and young people are affected, and even less discussion and evidence on how the climate crisis could affect violence against children.In this commentary, we review selected research to assess the links between the climate crisis and violence against children.We employ a social-ecological perspective as an overarching framework to organize findings from the literature and call attention to increased violence against children as a specific, yet under-examined, direct and indirect consequence of the climate crisis.Using such a perspective, we examine how the climate crisis exacerbates the risk of violence against children at the continually intersecting and interacting levels of society, community, family, and the individual levels. We propose increased risk of armed conflict, forced displacement, poverty, income inequality, disruptions in critical health and social services, and mental health problems as key mechanisms linking the climate crisis and heightened risk of violence against children. Furthermore, we posit that the climate crisis serves as a threat multiplier, compounding existing vulnerabilities and inequities within populations and having harsher consequences in settings, communities, households, and for children already experiencing adversities.We conclude with a call for urgent efforts from researchers, practitioners, and policymakers to further investigate the specific empirical links between the climate crisis and violence against children and to design, test, implement, fund, and scale evidence-based, rights-based, and child friendly prevention, support, and response strategies to address violence against children.

Peatlands are a type of wetlands that act as a carbon sink to prevent dead plant material from biodegrading and releasing carbon emissions into the atmosphere. Peatlands are currently being destroyed for the production of palm oil and other agricultural products, which releases greenhouse gases, that were previously confined underwater, into the atmosphere; these agricultural practices contribute to potentially catastrophic global warming events. Climate researchers seek to understand such impacts by collecting data on greenhouse gases that are released from Indonesian peatlands. However, current modes of collecting peatland emissions data are inadequate because they are expensive, non-portable, and not long-lasting. We seek to address these issues through the design and production of a floating greenhouse gas flux chamber that collects data from the water surface of peatlands. Thus, we created PEAT, the Peatlands Environmental Assessment Tool, which floats on a body of water, traps gases emitted from the surface, collects data on gas concentrations, and releases the gases in a continuous cycle. Our chamber integrates a methane and carbon dioxide sensor on a printed circuit board. PEAT is protected from humid environments, uses an actuated linear sliding door for venting, floats using a foam ring, can be easily tethered to a stationary object, and can collect data autonomously for one month before any maintenance is required. We conducted the following tests on PEAT: a flotation test that verified its ability to stabilize itself under rainy and windy conditions, a sealing test that verified the device can trap gases, a venting test that verified the device can reset greenhouse gas concentrations to ambient conditions, and desiccant lifespan test to ensure that the electronics will be kept at a safe humidity for the duration of autonomous data collection. The implication of PEAT’s robust design is a long-lasting, low-cost, and portable solution that supports the research of greenhouse gas emissions and can impact climate regulations.

Onion is not just an edible food compound but its seeds can also be an important source of valuable oil with various sensitive applications mainly in pharmaceutical, cosmetic and food fields. This has encouraged the use of a sustainable extraction technique like the supercritical CO2 extraction of oil from local onion seeds, as a clean and green alternative to organic solvent processes. To achieve this, the effects of four key operating parameters like pressure, temperature, particle size and CO2 mass flowrate were investigated in ranges of [150, 250 bars], [35, 65 °C], [0.25, 0.85 mm] and [50, 100 g/min], respectively, using a Box-Behnken experimental design, for a constant extraction time of 3 h. This led to optimal operating conditions of 250 bar, 57 °C, 0.25 mm and 50 g CO2/min for the best oil extraction yield value of 24.36%. Furthermore, gas chromatography-mass spectrometry (GC-MS) was used to identify qualitatively and quantitatively the chemical composition of the onion seed oils. About ten components were identified in the extracts, but with four major ones, namely 9,12-octadecadienoic acid, methyl ester, 9,12-octadecadienoic acid (Z,Z)-, methyl ester, 9-octadecadienoic acid (Z)-, methyl ester and hexadecanoic acid, methyl ester, present with significant percentages, depending on the operating parameters values. These fatty acids are well known for their benefits for human health. Finally this research showed ability of the supercritical CO2 extraction to induce a sustainability character while being performing in producing bioactive substances, excluding the use of organic solvent and even replacing classical and traditional techniques like hydrodistillation.

Improving our comprehension of infiltration processes in karst systems is crucial for a better adaptation to the global change regarding water resources availability and management. In this work, the effective recharge under different meteorological conditions and its transfer along the vertically distributed compartments of a geologically complex karst aquifer in southern Spain have been evaluated. Continuous records of soil moisture and temperature values (at 5 and 10 cm depth and the soil-rock transition -average depth of 28 cm-) have been combined with hourly hydrodynamic and hydrothermal responses recorded at two springs with a marked influence of the unsaturated zone (UZ) and the saturated zone (SZ), respectively.Most rainfalls generate soil moisture signal in the shallowest probes. However, a mean increase of soil water content of 10.5% in summer (from background values of 2.5%) and 6.1% in autumn-winter (from 9.6%) at the soil-rock interface were needed to produce hydrodynamic responses in the system: first in the spring related to the UZ, with a time delay of 4-9 hours after moisture peaks, and then (14-18 hours) in the spring draining the SZ, but only during autumn-winter recharge events. In addition, recharge caused decreases (up to 0.9°C) in the temperature of the water drained by the first spring, while lagged rises (up to 0.6°C) occurred in the second outlet.Transmission of the input signal would be favoured by stronger karstification, but the presence of inter-bedded detrital formations in the lithological sequence of the aquifer (partially confined in the SE border) filter and buffer groundwater flows before being drained by the spring related to the SZ. These findings will help to assess thresholds for effective infiltration and to predict groundwater recharge in karst aquifers under different climate change scenarios.

Sub-Saharan Africa (SSA) faces significant food security risks, primarily due to low soil fertility leading to low crop yields. Climate change is expected to worsen food security issues in SSA due to a combined negative impact on crop yield and soil fertility. A common omission from climate change impact studies in SSA is the interaction between change in soil fertility and crop yield. Integrated soil fertility management (ISFM), which includes the combined use of mineral and organic fertilizers, is expected to increase crop yield but it is uncertain how this advantage is maintained with climate change.   We explored the impact of scenarios of change in soil fertility and climate variables (temperature, rainfall, and CO2) on rainfed maize yield in four representative sites in SSA with no input and ISFM management. To do so, we used an ensemble of 15 calibrated soil-crop models. Reset and continuous simulations were performed to assess the impact of soil fertility vs climate change on crop yield. In reset simulations, SOC, soil N and soil water were reinitialized each year with the same initial conditions. In continuous simulations, SOC, soil N and soil water values of a given year were obtained from the simulation of the previous year, allowing cumulative effects on SOC and crop yields.Most models agreed that with current baseline (no input) management, yield changed by a much larger order of magnitude when considering declining soil fertility with baseline climate (-39%), compared with considering constant soil fertility but changes in temperature, rainfall and CO2 (from -12% to +5% depending on the climate variable considered). The interaction between change in soil fertility and climate variables only marginally influenced maize yield (high agreement between models). The model ensemble indicated that when accounting for soil fertility change, the benefits of ISFM systems over no-input systems increased over time (+190%). This increase in ISFM benefits was greater in sites with low initial soil fertility. We advocate for the urgent need to account for soil-crop long-term feedback in climate change studies to avoid large underestimations of climate change and ISFM impact on food production in SSA.

In many developing nations, modern energy sources are seen not only as cleaner and more efficient than traditional fuels, but also as important for achieving socio-economic development. Hence, from an energy policy perspective, households should switch to using modern energy sources. However, even when such sources are available, many households continue to use traditional fuels for cooking, often in combination with their modern counterparts. This study examines the effects of Dar es Salaam households' experience with using various fuels on fuel stacking behaviour and demand for individual fuels. The study finds a fuel-stacking behaviour, where most households combine LPG and charcoal for cooking. It also finds that households’ fuel choices are highly sensitive to their prior fuel-use experience. The results imply that achieving shifts to new fuels is easier if households have had at least some experience with those fuels. Hence, energy policies that aim to give households experience in using new fuels may make future energy switches easier to attain. Validerad;2025;Nivå 2;2025-06-11 (u8);Full text license: CC BY;This article is part of the special issue: Insights from the 2024 Global and African Energy Modelling Platform;This article has previously appeared as a manuscript in a thesis.