Early anthropogenic CH4 emissions and the variation of CH4 and (CH4)-C-13 over the last millennium

This study presents a new hypothesis to explain the observed variation of C

A State-Dependent Quantification of Climate Sensitivity Based On Paleodata of the Last 2.1 Million Years

The evidence from both data and models indicates that specific equilibrium climate sensitivity S[X]—the global annual mean surface temperature change (ΔTg) as a response to a change in radiative forcing X (ΔR[X])—is state dependent. Such a state dependency implies that the best fit in the scatterplot of ΔTg versus ΔR[X] is not a linear regression but can be some nonlinear or even nonsmooth function. While for the conventional linear case the slope (gradient) of the regression is correctly interpreted as the specific equilibrium climate sensitivity S[X], the interpretation is not straightforward in the nonlinear case. We here explain how such a state-dependent scatterplot needs to be interpreted and provide a theoretical understanding—or generalization—how to quantify S[X] in the nonlinear case. Finally, from data covering the last 2.1 Myr we show that—due to state dependency—the specific equilibrium climate sensitivity which considers radiative forcing of CO2 and land ice sheet (LI) albedo, math formula, is larger during interglacial states than during glacial conditions by more than a factor 2

Trans European decomposition index study in arable soils with different crop species diversity using 13C-labelled litter

Póster presentado en la Sessión 8 en el Joint European Stable Isotope Users group Meeting JESIUM 2022 Kuopio, Finland Online 10–14 October 2022.Mixed species systems are currently increasing in area in Europe providing opportunities for sustainable intensification of agriculture. The agroforestry systems cover about 9% of the utilized agricultural area and integrated crop livestock systems occupy a major place in the European agricultural area including perennial forage grasses and grasslands sown with varying degrees of duration. Intercropping and other mixed cash crop systems are currently less developed in the EU. The EU EJP-SOIL funded MIXROOT-C project (2021-2024) is gaining a management-oriented understanding of the effect of mixed-species root systems on carbon flow and organic matter accumulation in European agricultural soils.N

Rapid solubility and mineral storage of CO2 in basalt

The long-term security of geologic carbon storage is critical to its success and public acceptance. Much of the security risk associated with geological carbon storage stems from its buoyancy. Gaseous and supercritical CO2 are less dense than formation waters, providing a driving force for it to escape back to the surface. This buoyancy can be eliminated by the dissolution of CO2 into water prior to, or during its injection into the subsurface. The dissolution makes it possible to inject into fractured rocks and further enhance mineral storage of CO2 especially if injected into silicate rocks rich in divalent metal cations such as basalts and ultra-mafic rocks. We have demonstrated the dissolution of CO2 into water during its injection into basalt leading to its geologic solubility storage in less than five minutes and potential geologic mineral storage within few years after injection [1–3]. The storage potential of CO2 within basaltic rocks is enormous. All the carbon released from burning of all fossil fuel on Earth, 5000 GtC, can theoretically be stored in basaltic rocks [4]

Separating Forced from Chaotic Climate Variability over the Past Millennium

Reconstructions of past climate show notable temperature variability over the past millennium, with relatively warm conditions during the Medieval Climate Anomaly (MCA) and a relatively cold Little Ice Age (LIA). Multimodel simulations of the past millennium are used together with a wide range of reconstructions of Northern Hemispheric mean annual temperature to separate climate variability from 850 to 1950 CE into components attributable to external forcing and internal climate variability. External forcing is found to contribute significantly to long-term temperature variations irrespective of the proxy reconstruction, particularly from 1400 onward. Over the MCA alone, however, the effect of forcing is only detectable in about half of the reconstructions considered, and the response to forcing in the models cannot explain the warm conditions around 1000 CE seen in some reconstructions. The residual from the detection analysis is used to estimate internal variability independent from climate modeling, and it is found that the recent observed 50- and 100-yr hemispheric temperature trends are substantially larger than any of the internally generated trends even using the large residuals over the MCA. Variations in solar output and explosive volcanism are found to be the main drivers of climate change from 1400 to 1900, but for the first time a significant contribution from greenhouse gas variations to the cold conditions during 1600-1800 is also detected. The proxy reconstructions tend to show a smaller forced response than is simulated by the models. This discrepancy is shown, at least partly, to be likely associated with the difference in the response to large volcanic eruptions between reconstructions and model simulations

Progress in Self-Healing Fiber-Reinforced Polymer Composites

This paper sets out to review the current state of the art in applying self-healing/self-repair to high-performing advanced fiber-reinforced polymer composite materials (FRPs). A significant proportion of self-healing studies have focused so far on developing and assessing healing efficiency of bulk polymer systems, applied to particulate composites or low-volume fraction fiber-reinforced materials. Only limited research is undertaken on self-healing in advanced structural FRP composite materials. This review focuses on what is achieved to date, the ongoing challenges which have arisen in implementing self-healing into FRPs, how considerations for industrialization and large-scale manufacture must be considered from the outset, where self-healing may provide most benefits, and how a functionality like self-healing can be validated for application in real structures. Systems are compared in terms of process parameters, resulting mechanical properties, methods of healing assessment, as well as values of healing quantification. Guidelines are further given for a concerted effort to drive toward standardization of tests and the use of specific reinforcement architectures in order to allow reliable comparison between the available healing systems in structural composites

Preparation of liposomes: A novel application of microengineered membranes–From laboratory scale to large scale

This article was accepted for publication in the journal, Colloids and Surfaces B: Biointerfaces [© Elsevier B.V.] and the definitive version is available at: http://dx.doi.org/10.1016/j.colsurfb.2013.07.066A novel ethanol injection method using microengineered nickel membrane was employed to produce POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and Lipoid® E80 liposomes at different production scales. A stirred cell device was used to produce 73 ml of the liposomal suspension and the product volume was then increased by a factor of 8 at the same transmembrane flux (140 l m−2 h−1), volume ratio of the aqueous to organic phase (4.5) and peak shear stress on the membrane surface (2.7 Pa). Two different strategies for shear control on the membrane surface have been used in the scaled-up versions of the process: a cross flow recirculation of the aqueous phase across the membrane surface and low frequency oscillation of the membrane surface (∼40 Hz) in a direction normal to the flow of the injected organic phase. Using the same membrane with a pore size of 5 μm and pore spacing of 200 μm in all devices, the size of the POPC liposomes produced in all three membrane systems was highly consistent (80–86 nm) and the coefficient of variation ranged between 26 and 36%. The smallest and most uniform liposomal nanoparticles were produced in a novel oscillating membrane system. The mean vesicle size increased with increasing the pore size of the membrane and the injection time. An increase in the vesicle size over time was caused by deposition of newly formed phospholipid fragments onto the surface of the vesicles already formed in the suspension and this increase was most pronounced for the cross flow system, due to long recirculation time. The final vesicle size in all membrane systems was suitable for their use as drug carriers in pharmaceutical formulations

Low atmospheric CO2 levels during the Little Ice Age due to cooling-induced terrestrial uptake

Low atmospheric carbon dioxide (CO2) concentration during the Little Ice Age has been used to derive the global carbon cycle sensitivity to temperature. Recent evidence confirms earlier indications that the low CO2 was caused by increased terrestrial carbon storage. It remains unknown whether the terrestrial biosphere responded to temperature variations, or there was vegetation re-growth on abandoned farmland. Here we present a global numerical simulation of atmospheric carbonyl sulfide concentrations in the pre-industrial period. Carbonyl sulfide concentration is linked to changes in gross primary production and shows a positive anomaly during the Little Ice Age. We show that a decrease in gross primary production and a larger decrease in ecosystem respiration is the most likely explanation for the decrease in atmospheric CO2 and increase in atmospheric carbonyl sulfide concentrations. Therefore, temperature change, not vegetation re-growth, was the main cause of the increased terrestrial carbon storage. We address the inconsistency between ice-core CO2 records from different sites measuring CO2 and δ13CO2 in ice from Dronning Maud Land (Antarctica). Our interpretation allows us to derive the temperature sensitivity of pre-industrial CO2 fluxes for the terrestrial biosphere (γL = -10 to -90 Pg C K-1), implying a positive climate feedback and providing a benchmark to reduce model uncertainties

Understanding the glacial methane cycle.

Atmospheric methane (CH4) varied with climate during the Quaternary, rising from a concentration of 375 p.p.b.v. during the last glacial maximum (LGM) 21,000 years ago, to 680 p.p.b.v. at the beginning of the industrial revolution. However, the causes of this increase remain unclear; proposed hypotheses rely on fluctuations in either the magnitude of CH4 sources or CH4 atmospheric lifetime, or both. Here we use an Earth System model to provide a comprehensive assessment of these competing hypotheses, including estimates of uncertainty. We show that in this model, the global LGM CH4 source was reduced by 28-46%, and the lifetime increased by 2-8%, with a best-estimate LGM CH4 concentration of 463-480 p.p.b.v. Simulating the observed LGM concentration requires a 46-49% reduction in sources, indicating that we cannot reconcile the observed amplitude. This highlights the need for better understanding of the effects of low CO2 and cooler climate on wetlands and other natural CH4 sources

Past and future carbon fluxes from land use change, shifting cultivation and wood harvest

Carbon emissions from anthropogenic land use (LU) and land use change (LUC) are quantified with a Dynamic Global Vegetation Model for the past and the 21st century following Representative Concentration Pathways (RCPs). Wood harvesting and parallel abandonment and expansion of agricultural land in areas of shifting cultivation are explicitly simulated (gross LUC) based on the Land Use Harmonization (LUH) dataset and a proposed alternative method that relies on minimum input data and generically accounts for gross LUC. Cumulative global LUC emissions are 72 GtC by 1850 and 243 GtC by 2004 and 27–151 GtC for the next 95 yr following the different RCP scenarios. The alternative method reproduces results based on LUH data with full transition information within <0.1 GtC/yr over the last decades and bears potential for applications in combination with other LU scenarios. In the last decade, shifting cultivation and wood harvest within remaining forests including slash each contributed 19% to the mean annual emissions of 1.2 GtC/yr. These factors, in combination with amplification effects under elevated CO2, contribute substantially to future emissions from LUC in all RCPs