101 research outputs found
Il sistema Terra tra passato e futuro
No full textIntroduzione al volume "Ambiente e società", appendice 2014 del Grande Dizionario Enciclopedico di UTET Grandi Opere. Autori: N. Myers, A. Romano, F. Cavalli Sforza, G. Martinotti, M. Flores, G. Martignetti, C. Acaia, G. Alberti, S. Caserini, A. Navarra, L. Maffi, I. Hanski, G. Alfani, S. Bocchi, M. Mandrioli, U. Morelli, P. Laureano, M. Ferrari, U. Bardi, E. Padoa-Schioppa, F. Palmeri, I. Musu, A. Boscaro, S. Mazzotti, L. Fantacci, S. Nespor
Global climate change
No full textGlobal climate change is happening and an overwhelming majority of the scientific community consider the risk of climate change real and severe. The knowledge summary in Fifth Assessment Report (AR5) of the Intergovernmental Panel on climate change (IPCC, 2014a), 1 provided new evidence of the reality of climate change, on the basis of many independent analyses from observations of the climate system, paleoclimate archives, theoretical studies of climate processes and simulations using climate models
Methane emissions from small residential wood combustion appliances: Experimental emission factors and warming potential
No full textMethane emission factors (g/GJ) were determined testing residential heating biomass appliances (6–11 kW) under real-world operating conditions. User behavior for manually load appliances was simulated following a loading scheme starting from the cold start conditions, followed by two nominal batches and a final batch either with the nominal load of the appliance or by over loading the firebox (closing the air valves) and lasted until burn out. The results were analyzed both on batch-per-batch basis and for total combustion cycle from cold start to burn out in order to determine the critical situations causing high methane emissions. For comparison two automatic pellet appliances (8–25 kW) were also tested. Emission factors (EFs) for these automatic appliances are more than an order of magnitude lower with respect to batch-working room heaters. For the latter the average EFs ranged from 142 g/GJ to 238 g/GJ and showed both batch-to-batch and inter-appliance variability; however, many of the observed differences were not statistically significant. The results highlighted the importance of the user behavior to avoid high methane emissions. The climate relevance of methane emission levels has been assessed using global warming potential (GWP) taken from the literature, comparing CO2equivalent emissions with that of N2O and other near-term climate forcers (CO, NOx, VOC, black carbon) emitted by the same appliances. The results show that the warming impact of CH4 is lower than that of BC and CO (compounds emitted in relevant levels in small appliances burning wood), but is still an important portion of the CO2 avoided for the substitution of fossil fuels with biomass. Although the uncertainties associated with GWP are large and EFs are based on a limited number of appliances and fuel types, the results show that in the short term (i.e., 20-year period) CO2eq for all the non-CO2 forcers offset the CO2 benefits of biomass use
IMPARARE DALLE CATASTROFI
No full textIl testo prosegue le ricerche sulla pedagogia delle catastrofi, in collaborazione con un climatologo, ed in relazione con i più recenti eventi sociali ed ambientali
10 ANNI DI CAMBIAMENTI CLIMATICI: IL PESO DEI RITARDI E I PRIMI TIMIDI SEGNALI DI AZIONE
No full textSe negli ultimi 10 anni gli effetti del riscaldamento globale sono diventati sempre più evidenti, come del resto previsto dalla comunità scientifica, è cresciuta anche la risposta
globale alla crisi climatica, seppure in modo del tutto insufficiente rispetto a quanto necessario per stabilizzare l’aumento delle temperature globali. I continui record delle temperature globali, uniti ad un aumento degli impatti delle ondate di calore e degli estremi di precipitazione, sempre più percepibili, mostrano l’urgenza di un’azione maggiormente incisiva contro il cambiamento climatico. L’articolo passa in rassegna l’andamento dei principali fattori climalteranti, di alcuni indicatori del riscaldamento globale, nonché delle principali tendenze nelle azioni di contrasto alla crisi climatica.If in the last 10 years the effects of global warming are increasingly evident, as predicted by the scientific community, the global response to the climate crisis has grown, albeit in a completely insufficient way compared to what is necessary to stabilise the increase in global temperatures. Continued global temperature records, coupled with an increasing impact of heat waves and precipitation extremes, show the urgency of the need for action against climate change. The article reviews the trend of the main climate-changing factors, some indicators of global warming, as well as the main trends in actions to combat the climate crisis
CO2 submarine storage in glass containers: life cycle assessment and cost analysis of four case studies in the cement sector
No full textSince carbonation of cement materials over their life cycle represents a large and growing net sink of CO2 (Xi et al., 2016), the capture and storage of CO2 emissions during the production of cement leads to negative emissions. This paper describes the application of a new patented technology for the storage of CO2 in glass containers into the deep seabed (Submarine Carbon Storage, SCS), to cement plants located in four different locations in the world (Italy, Spain, Bulgaria, and Morocco; cases A, B, C, and D respectively). This technology is based on the bottling of liquid CO2 at high pressure in capsules made of glass that are sent to the bottom of the ocean by a proper pipeline. A Life Cycle Assessment that considers all the stages of the process and twelve impact categories, with a focus on the climate change category, showed an average impact of 0.11 tCO2eq per ton of CO2 stored for Case A, 0.084 for B, 0.086 for C and 0.132 for D. The part of the process with the highest GHG impact is the capsule production, due to the consumption of natural gas and electricity and to the calcination taking place during the production of glass. The cost analysis has included the capital costs (glass furnace, machinery, infrastructures, engineering, procurement & construction) and the operational costs (energy consumption, labor costs, materials, long-term monitoring), considering also the funding structure through financing and equity. The costs of the four case studies, 29 /tCO2 for case B, 16 /tCO2 for case D, are in the range identified in Caserini et al. (2017). The CAPEX is quite similar between the four cases, whereas the OPEX cost variation is larger; the parameters that most affected the cost were the electricity price, the natural gas price and the amount of CO2 stored (tied to the size of the cement plant). Although further work is needed to assess in detail some critical aspects of the design, the result of this stage of the research allows concluding that the application of the SCS in cement plants could represent an interesting option for negative emissions, but the contribution of cement-based products as a negative emissions source is limited due the slowness of CO2 uptake during the lifetime of cement materials
An overview of nitrogen oxides emissions from biomass combustion for domestic heat production
No full textIn order to fulfill the European Union's climate and energy goals, the heating and cooling sector must cut its use of fossil fuels. Solid biomass can constitute an alternative to fossil fuels as a renewable and carbon-neutral source of energy but there are some aspects to biomass combustion in small-scale domestic appliances that can compromise the environmental sustainability of this renewable energy source in terms of burden on air quality. The priority pollutants in this respect are particulate matter and nitrogen oxides. While particulate matter emissions are often discussed, nitrogen oxides emissions from domestic heating appliances are relatively less in the center of attention. The aim of the present study is to review the literature regarding the nitrogen oxides emissions from this emission source discussing the main formation mechanisms and the state-of-the-art control techniques, as well as the influence of fuel composition (especially fuel bound nitrogen), heating appliance type and operating conditions with the help of the gathered experimental emission factors data. The review crosslinks several aspects usually treated separately in scientific papers (e.g., only laboratory tests with basic theory or only field tests on emission levels etc.), providing thus a quick reference tool to the state-of-the-art knowledge on this topic
Do the non-co2 climate forcers offset the co2 benefit of biomass use for residential heating?
No full textThe climate relevance of non-CO2 emission levels from small appliances burning wood and pellet in the residential sector has been assessed using data for the combustion of woody biomasses and global warming potential (GWP) taken from the literature, considering a short reference period (20-years) where very strong emission reductions should be implemented to stay within the Paris Agreement targets. CO2equivalent emissions from CH4, N2O and short-lived gases and aerosols (CO, NOx, NMVOC, black carbon and organic carbon) emitted by small appliances in Lombardy is 1% of total CO2eq in the region (in a 20-year reference period), and offsets half of the CO2 uptake during the growth of the same amount of biomass burnt. Results show that the use of biomass in these appliances instead of natural gas does not have any benefits in terms of CO2 equivalent emissions reduction if 20 years is considered. Although from one side the uncertainties associated with GWP are large and EFs are based on a limited number of appliances and fuel types, other approach (i.e. dynamic life cycle) could lead to yet lower GHG benefits from biomass use that reinforce the conclusion of this work based on the role of non-CO2 forcers
Organic and inorganic trace pollutants around municipal solid waste incinerators: results from air quality monitoring campaigns in Northern Italy
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