Biomass burning is a major source of carbonaceous aerosols that significantly influences the Earth's radiation balance. However, the spectral light absorption properties of biomass burning aerosols (BBAs), particularly the contribution of brown carbon (BrC), remain poorly constrained due to reliance on laboratory measurements that may not accurately represent real-world atmospheric conditions. To address this limitation, we developed an unmanned aerial vehicle (UAV) based-platform for direct in-situ measurements of BBAs in the ambient atmosphere over the rural North China Plain. This approach reduces biases inherent to laboratory chamber experiments and enables a more realistic characterization of BBAs absorption properties. Our measurements revealed that the absorption & Aring;ngstr & ouml;m exponent (AAE) for typical residential biomass burning was 3.70 +/- 0.04 under smoldering conditions and 1.50 +/- 0.08 under flaming conditions. Variations in AAE were driven primarily by combustion conditions and smoke humidity rather than fuel type. Additionally, field-observed OC/EC ratios were up to ten times higher than those reported in laboratory chamber studies, resulting in systematically lower mass absorption cross-sections. This finding suggests that the BBAs light absorption and radiative forcing estimates in the North China Plain may be systematically overestimated by chamber-based studies. Notably, under smoldering conditions, BrC absorption at 375 nm was up to 6.6 times greater than that of black carbon (BC) once mass emissions are considered, emphasizing that strategies aiming at reducing smoldering combustion could be particularly effective in mitigating the ultraviolet radiative effects of BBAs. Our results demonstrate that ambient atmospheric measurements are essential for accurately constraining BBAs absorption properties and their climate impacts.
Brown carbon (BrC) aerosols play a significant role in atmospheric radiative forcing, particularly in the Arctic where they could potentially contribute to surface warming. However, their regional variability and sources in the open ocean remain poorly understood. To address this, we conducted ship-based aerosol measurements aboard the R/V Mirai during the MR18-05C research cruise (October-December 2018), spanning the western North Pacific, Bering Sea, and Arctic Ocean. We examined BrC optical properties alongside PM2.5 chemical composition, trace gases, and meteorological conditions to assess its variability and sources. Our results reveal a drastic northward decline in BrC levels, with light absorption capability in the Bering Sea and the Arctic approximately 50% lower than those in the western North Pacific. The strongest BrC absorption was observed in regions influenced by crop residue burning in Northeast China. In the Arctic, BrC remained low as the main footprint is within the Arctic alongside limited BrC sources, although occasionally affected by long-range transport. Chemical composition analysis highlights biomass burning and fossil fuel emissions as dominant BrC sources in the western North Pacific. Solubility analysis indicated that BrC in the Arctic was predominantly water soluble, increasing its susceptibility to wet scavenging. A strong high-pressure system (1027 +/- 6.2 hPa) over the Arctic (November 9-17) led to aerosol accumulation, although BrC remained low. This study underscores the complex interplay between regional emissions, long-range transport, and atmospheric processing in regulating BrC distributions across latitudinal gradients. Our findings highlight the importance of source-region emissions and transport pathways in determining BrC fate in the Arctic, with implications for understanding its role in climate forcing.
The present study performed classification global aerosols based on particle linear depolarization ratio (PLDR) and single scattering albedo (SSA) provided from AErosol RObotic NETwork (AERONET) Version 3.0 and Level 2.0 inversion products of 171 AERONET sites located in six continents. Current methodology could distinguish effectively between dust and non-dust aerosols using PLDR and SSA. These selected sites include dominant aerosol types such as, pure dust (PD), dust dominated mixture (DDM), pollution dominated mixture (PDM), very weakly absorbing (VWA), strongly absorbing (SA), moderately absorbing(MA), and weakly absorbing (WA). Biomass-burning aerosols which are associated with black carbon are assigned as combinations of WA, MA and SA. The key important findings show the sites in the Northern African region are predominantly influenced by PD, while south Asian sites are characterized by DDM as well as mixture of dust and pollution aerosols. Urban and industrialized regions located in Europe and North American sites are characterized by VWA, WA, and MA aerosols. Tropical regions, including South America, South-east-Asia and southern African sites which prone to forest and biomass-burning, are dominated by SA aerosols. The study further examined the impacts by radiative forcing for different aerosol types. Among the aerosol types, SA and VWA contribute with the highest (30.14 +/- 8.04 Wm-2) and lowest (7.83 +/- 4.12 Wm-2) atmospheric forcing, respectively. Consequently, atmospheric heating rates are found to be highest by SA (0.85 K day-1) and lowest by VWA aerosols (0.22 Kday-1). The current study provides a comprehensive report on aerosol optical, micro-physical and radiative properties for different aerosol types across six continents.
Bioindication is a key tool for monitoring habitat quality and ecosystem dynamics under increasing anthropogenic pressure. Among model organisms, ground beetles (Coleoptera: Carabidae) play a particularly important role, and one of the widely applied functional indicators describing their assemblage structure is the Mean Individual Biomass (MIB). Introduced in the 1980s, this index reflects the average body mass of Carabidae and allows assessment of successional stages. Its computational simplicity and intuitive interpretation have led to its application in forests, agricultural landscapes, post-industrial areas, and glacier forelands. This paper synthesizes the development and applications of the MIB, highlighting both its advantages and methodological limitations (including variability of length-mass models, seasonal activity patterns, and dependence on sampling methods). Particular attention is given to the potential of the MIB in the context of global environmental change, including its role as an indicator of ecosystem responses to climate change and processes related to soil carbon sequestration. Based on a literature review, future research directions are identified, encompassing methodological standardization, integration of MIB with other ecological and molecular indicators, and expansion of analyses to regions beyond Europe. By linking classical bioindication with ecosystem functioning studies, the MIB may serve as a universal tool for environmental monitoring and the assessment of ecosystem services under accelerated global change.
Permafrost thawing is a critical climate tipping point, with catastrophic consequences. Existing stabilization methods rely on refrigerant-based systems, such as thermosyphons and active refrigeration, which are capital-intensive, energy-demanding, or increasingly ineffective in warming climates. Most infrastructure built on permafrost requires continuous heat removal from the foundation as the underlying permafrost becomes progressively unstable. To address these challenges, we demonstrate a fully biomass-derived cooling geotextile that can effectively mitigate permafrost thawing through scalable nanoprocessing via a roll-to-roll fabrication (1.3 mmin-1). The cooling geotextile features a hierarchical three-layer design: a strong woven biomass scaffold, a permeable nonwoven fiber network, and an optimized porous coating layer with micro- and nano-structures. When anchored to bare ground, it extracts heat to the cold sky, enhances albedo from similar to 30% to 96.3%, and establishes a thermal barrier between soil and air. Engineered for Arctic durability, it withstands strong winds, extreme cold, and freeze-thaw cycles, exceeding the American National Engineering Handbook requirements (tensile strength 1,682 kg; tear strength 191 kg; puncture strength 61 kg). Field tests in West Lafayette, IN (40 degrees 25 ' 21 '' N, 86 degrees 55 ' 12 '' W) reveal up to 25 degrees C soil cooling under 500 Wm-2 irradiance. Its lightweight (0.8 kgm-2) and rollable attributes enable scalable and fast localized deployment. Simulations predict up to 12 degrees C surface cooling during Arctic summer (2020-2050), preventing up to 40,000 km2 of permafrost from thawing. Completely derived from biomass, cooling geotextile ensures a low carbon footprint (0.7 kgm-2), positioning itself as a sustainable solution for reinforcing Arctic coastline, reconstructing thawing landscape, and restoring the environment.
The recent large reduction in anthropogenic aerosol emissions across China has improved China's air quality but has potential consequences for climate forcing. This sharp reduction in anthropogenic emissions has occurred against a background influenced by changing regional biomass burning emissions over a similar period of time. Here, we use the UK Earth System Model (UKESM) to estimate aerosol instantaneous radiative forcing (IRF) due to changes in emissions of aerosols and precursors from biomass burning and anthropogenic sources (separately and in combination) over 2008-2016, with a focus on China and regions downwind. We also separately quantify the IRF due to changes in anthropogenic aerosol emissions inside China (CHN) and the Rest Of the World (ROW). Reductions in Chinese anthropogenic emissions of BC, SO2 and OC contributed -0.30 +/- 0.01, +1.00 +/- 0.04, and +0.05 +/- 0.01 W m-2, respectively to IRF over China, accounting for similar to 97% of the total local anthropogenic aerosol IRF. These emission changes contributed a remote regional IRF of 0.22 +/- 0.04 W m-2 over the North Pacific Ocean. The reduction in SO2 emissions from China contributed a global IRF of equal magnitude to that from SO2 emissions from ROW (similar to 0.08 W m-2). Changes in global biomass burning emissions contributed 0.03 W m-2 (equivalent to over 20% of the magnitude of anthropogenic aerosol IRF), enhancing the global anthropogenic aerosol IRF, whereas they partly offset the anthropogenic IRF over China. Meanwhile, biomass burning emissions dominated the total IRF (around 98%) over the Arctic.
Use of forest biomass may induce changes in the aerosol emissions, with subsequent impacts on the direct and indirect climate effects of these short-lived climate forcers. We studied how alternative wood use scenarios affected the aerosol emissions and consequent radiative forcing in Finland. In all alternative scenarios, the harvest level of forest biomass was increased by 10 million m3 compared to the baseline. The increased biomass harvest was assigned to four different uses: (i) to sawn wood, (ii) to pulp-based products, (iii) to energy biomass combusted in small-scale appliances or (iv) to energy biomass combusted in medium-to-large scale boilers. Aerosol emissions (black carbon (BC), organic carbon (OC) and sulphur dioxide (SO2)) under these scenarios were estimated using displacement factors (DFs). The global aerosol-climate model ECHAM-HAMMOZ was used to study instantaneous radiative forcing due to aerosol-radiation interactions (IRFARI) and effective radiative forcing (ERF), based on the differences in aerosol emissions between the alternative wood use scenarios and the baseline scenario. The results indicated that the use of sawn wood and energy biomass combusted in medium- to large-scale boilers decreased radiative forcings, implying climate cooling, whereas the increased use of pulpwood increased them. Energy biomass combustion in small-scale appliances increased IRFARI by 0.004 W m-2 but decreased ERF by -0.260 W m-2, specifically due to a strong increase in carbonaceous aerosols. Alternative use of forest biomass notably influenced aerosol emissions and their climate impacts, and it can be concluded that increased forest biomass use requires a comprehensive assessment of aerosol emissions alongside greenhouse gases (GHGs). Given the consequent reduction in radiative forcing from aerosol emissions, we conclude that the greatest overall climate benefits could be achieved by prioritising the production of long-lived wood-based products.
Drought and soil nitrogen (N) deficiency are the limiting factors for poplar plantation productivity improvement in semi-arid regions. N addition could alleviate the growth decline of trees caused by drought; however, the effectiveness under severe drought and the underlying ecophysiological understanding remains uncertain. To further clarify the mechanisms of N addition in regulating tree biomass accumulation under different drought levels, we investigated the effects of 6 g NH4NO3 per plant addition on the carbon and N assimilation and biomass accumulation of potted poplar seedlings under moderate or severe drought (40 % or 20 % of field capacity) conditions, with a particular emphasis on carbon and N interactions. We found that under moderate drought, N addition markedly promoted the activities of antioxidases, nitrate reductase (39 %), and N concentration (56 %) in leaves, significantly alleviated the damages of the membranes and photosystem II, and increased both leaf area (69 %) and chlorophyll content per unit leaf area, along with net photosynthesis rate (34 %), thereby significantly alleviating growth restrictions. However, under severe drought, although N addition increased the accumulation of both soluble sugars and N of the whole plant, it did not ameliorate the damage to membranes and photosystem II, nor did it improve chlorophyll content, leaf area, or biomass accumulation. Therefore, N addition could increase leaf area, enhance antioxidants, and positively influence leaf carbon assimilation (0.60, p < 0.001) in poplar seedlings under moderate drought. The restrictions on leaf area and carbon assimilation were exacerbated during severe drought, which mitigated the positive effects of N addition on carbon assimilation and biomass accumulation. The findings of this study suggest that the growth of hybrid poplar can be enhanced by applying N fertilizer under mild drought conditions. In contrast, N fertilization has no significant effect in severe drought conditions.
The majority of European forests are managed and influenced by natural disturbances, with wind being the dominant agent, both of which affect the ecosystem's carbon budget. Therefore, investigating the combined effect of wind damage and different soil preparation practices on forest carbon pools is of great importance. This study examines changes in carbon stocks in the soil and biomass of two 5-year-old Scots pine stands (namely Tlen1 and Tlen2), which were established approximately 2 years after a large-scale wind disturbance in northwestern Poland. These neighboring sites differ in terms of the reforestation methods applied, particularly regarding soil preparation: ploughing disc trenching at Tlen1 and partial preparation through local manual scalping at Tlen2. Using nearby forest soils as the best available reference for the pre-windthrow state, it was estimated that the total carbon stock in the soil (up to 50 cm depth, both organic and mineral) was depleted by approximately 17 % at Tlen1 and 7 % at Tlen2. The between-site differences were around 18 %, which nearly doubled when considering only the top 20 cm of the soil profile. In contrast, the total biomass, as well as the carbon stock in biomass, were significantly higher at the site with soil prepared using moderate ploughing (Tlen1) compared to the area with partial soil preparation (Tlen2). Our findings indicate that ploughing disc trenching, aimed mainly at weed removal and improving soil properties, significantly enhanced Scots pine seedlings' growth, survival, and development during the first four years after planting. Finally, when both carbon stock estimates are pooled together, regardless of the chosen technique, the growing biomass in the investigated stands did not fully compensate for the carbon losses caused by mechanical soil preparation. However, in the short term, the overall change in the ecosystem's carbon balance was only slightly negative and comparable between the two sites.
Sustainable polymers have attracted interest due to their ability to biodegrade under specific conditions in soil, compost, and the marine environment; however, they have comparatively lower mechanical properties, limiting their widespread use. This study explores the effect of incorporating waste soy biomass into sustainable polymers (including biodegradable and biobased) on the thermal and mechanical properties of the resultant blends. The dispersion of the waste soy biomass in the polymer matrix is also investigated in relation to particle size (17 mu m vs. 1000 mu m). Fine waste soy biomass did not significantly affect the melting temperature of the polymers (polyhydroxyalkanoates, polybutylene adipate terephthalate, polybutylene adipate terephthalate/poly(lactic) acid, and biobased linear low-density polyethylene) used in this study, but their enthalpy of fusion decreased after soy was melt-blended with the polymers. The tensile modulus of the polymers filled with fine waste soy biomass powder (17 mu m) was enhanced when melt-blended as compared to unfilled polymers. Additionally, it was found that fine waste soy powder (17 mu m) increased the tensile modulus of the polymer blends without significantly affecting processability, while coarse waste soy meal (1000 mu m) generally reduced elongation at break due to poor dispersion and stress concentration; however, this effect was less pronounced in PHA blends, where improved compatibility was observed.