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While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosystem models forced with two Earth system models and four emission scenarios with and without fishing. We derive average biomass trends and associated uncertainties across the marine food web. Without fishing, mean global animal biomass decreased by 5% (±4% SD) under low emissions and 17% (±11% SD) under high emissions by 2100, with an average 5% decline for every 1 °C of warming. Projected biomass declines were primarily driven by increasing temperature and decreasing primary production, and were more pronounced at higher trophic levels, a process known as trophic amplification. Fishing did not substantially alter the effects of climate change. Considerable regional variation featured strong biomass increases at high latitudes and decreases at middle to low latitudes, with good model agreement on the direction of change but variable magnitude. Uncertainties due to variations in marine ecosystem and Earth system models were similar. Ensemble projections performed well compared with empirical data, emphasizing the benefits of multimodel inference to project future outcomes. Our results indicate that global ocean animal biomass consistently declines with climate change, and that these impacts are amplified at higher trophic levels. Next steps for model development include dynamic scenarios of fishing, cumulative human impacts, and the effects of management measures on future ocean biomass trends.

AbstractGlobal impact models represent process-level understanding of how natural and human systems may be affected by climate change. Their projections are used in integrated assessments of climate change. Here we test, for the first time, systematically across many important systems, how well such impact models capture the impacts of extreme climate conditions. Using the 2003 European heat wave and drought as a historical analogue for comparable events in the future, we find that a majority of models underestimate the extremeness of impacts in important sectors such as agriculture, terrestrial ecosystems, and heat-related human mortality, while impacts on water resources and hydropower are overestimated in some river basins; and the spread across models is often large. This has important implications for economic assessments of climate change impacts that rely on these models. It also means that societal risks from future extreme events may be greater than previously thought.

Carbon capture and storage (CCS) has been proposed as a potential technology to mitigate climate change. However, there is currently a huge gap between the current global deployment of this technology and that which will be ultimately required. Whilst CO2 can be captured at any geographic location, storage of CO2 will be constrained by the geological storage potential in the area the CO2 is captured. The geological storage potential can be evaluated at a very high level according to the tectonic setting of the target area. To date, CCS deployment has been restricted to more favourable tectonic settings, such as extensional passive margin and post-rift basins and compressional foreland basins. However, to reach the adequate level of deployment, the potential for CCS of regions in different tectonic settings needs to be explored and assessed worldwide. Surprisingly, the potential of compressional basins for carbon storage has not been universally evaluated according to the global and regional carbon emission distribution. Here, we present an integrated source-to-sink analysis tool that combines comprehensive, open-access information on basin distribution, hydrocarbon resources and CO2 emissions based on geographical information systems (GIS). Compressional settings host some of the most significant hydrocarbon-bearing basins and 36% of inland CO2 emissions but, to date, large-scale CCS facilities in compressional basins are concentrated in North America and the Middle East only. Our source-to-sink tool allows identifying five high-priority regions for prospective CCS development in compressional basins: North America, north-western South America, south-eastern Europe, the western Middle East and western China. We present a study of the characteristics of these areas in terms of CO2 emissions and CO2 storage potential. Additionally, we conduct a detailed case-study analysis of the Sichuan Basin (China), one of the compressional basins with the greatest CO2 storage potential. Our results indicate that compressional basins will have to play a critical role in the future of CCS if this technology is to be implemented worldwide. This research was performed within the framework of DGICYT Spanish Projects CGL2015-66335-C2-1-R and PGC2018-093903-B-C22, Grup Consolidat de Recerca “Geologia Sedimentària” (2017-SGR-824), and was also funded by the China Scholarship Council (CSC) (201806450043). JA received funding by EIT Raw Materials – SIT4ME Project (17024) and is now funded by MICINN (Juan de la Cierva fellowship - IJC2018-036074-I). EGR acknowledges funding by the AGAUR (Agència de Gestió d’Ajuts Universitaris i de Recerca) of the Generalitat de Catalunya (“Beatriu de Pinós” fellowship 2017SGR-824) and the Spanish Ministry of Science, Innovation and Universities (“Ramón y Cajal” fellowship RYC2018-026335-I). GJ is funded by the University of Strathclyde Faculty of Engineering. Peer reviewed

In order to make further progress in the field of reducing mercury emissions to the atmosphere, it is necessary to develop efficient and economically viable technologies. Low-cost solid sorbents are a candidate technology for mercury capture. However, kinetic models are required to predict the adsorption mechanism and to optimize the design of the process. In this study, several low-cost materials (biomass chars) were evaluated for the removal of gas-phase elemental mercury and kinetic studies were performed to investigate the mechanism of mercury adsorption. These kinetic studies were also used to predict the behavior of a fixed-bed column. The models applied were pseudo-first-order and pseudo-second-order equations, Fick’s intraparticle diffusion model, and the Yoon–Nelson model. The chars obtained from the gasification of plastic-paper waste demonstrated the best behavior for mercury capture because of their high Brunauer–Emmett–Teller surface area, large total pore volume (mainly micropore volume), and high chlorine content. The Yoon–Nelson model provided a better fitting for the samples with low mercury retention capacities, while in the case of the plastic-paper chars, all of the models provided relatively accurate predictions because their highly microporous structure retarded the internal diffusion process and their increased chlorine content enhanced chemisorption on their surface. The authors thank the project CTM2011-22921, the Energy Research Centre of the Netherlands (ECN) for supplying the chars employed in this study and the Spanish Research Council (CSIC) for awarding Ms. Aida Fuente-Cuesta a pre-doctoral fellowship and for financing her a stay at the Aristotle University of Thessaloniki (Greece). Peer reviewed

20 figures, 5 tables. An important percentage of biogas is made of CO2, which decreases its heating value. If CO2 is adsorbed two advantages can be achieved: CO2 capture and the increase of biogas heating value. Biomethane is a renewable fuel, which can provide energy autonomy and a reduction of greenhouse gases emissions. CO2 capture from power plants by using solid adsorbents is an effective method for the reduction of CO2 emission and an excellent solution for methane enrichment of biogas. This work evaluates the CO2 removal and methane enrichment of biogas by adsorption of gas molecules to solid surfaces of sorbents in a pilot-scale biogas upgrading system. The materials selected to remove CO2 from gases were three: calcium hydroxide, commercial activated carbon and solid amine adsorbent, loaded on commercial activated carbon. The amine adsorbent used in this work was polyethylenimine (PEI). The adsorbents were characterized by thermal stability through thermogravimetric analyzer (TGA), X-ray diffraction analysis (XRD), specific area, pore size distribution and particle size distribution. The CO2 adsorption capacities of the sorbents were measured using a thermogravimetric analyzer with pure CO2 at atmospheric pressure. The CO2 adsorption capacity test was 0.00653 mol/g for calcium hydroxide, 0.00219 mol/g for commercial activated carbon with 0,1 wt% of amine and 0.00168 mol/g for commercial activated carbon. The effect of adsorbent dosage as a function of time was also investigated. The result showed that the CO2 adsorption of the sorbents increases with adsorbent dosage. The results obtained from the upgrading tests conducted in the lab-scale system showed that a purity of 99.9 % methane was obtained using 15 g of calcium hydroxide, a purity of methane of 87 % was obtained using 30 g of commercial activated carbon with 0.1 wt% amine and a purity around 86 % methane was obtained using 30 g of commercial activated carbon. The authors would like to thank H2CU for the possibility of performing the exchange with the Columbia University. Authors want to acknowledge for funding, the project: “Technical, Environmental and Socio-Economic study of power-to-fuel solutions for a sustainable path towards a green future: achieving 80 % renewable electric energy and 40 % renewable primary energy supply within the next two decades”. Funded in 2020 by PRIN Italian national funds and registered with the code: 2020AA9N4M. This work has been funded by the GTCLC-NEG project that has received funding from the Euro-pean Union’s Horizon 2020 research and innovation programme under the Marie Sklodow-ska-Curie grant agreement No. 101018756. Peer reviewed