1,721,002 research outputs found
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
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
An overview of nitrogen oxides emissions from biomass combustion for domestic heat production
Full text linkIn 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
Carbon dioxide submarine storage in glass containers: Life Cycle Assessment and cost analysis of four case studies in the cement sector
Full text linkThis paper describes the potential application of a new patented technology for the storage of carbon dioxide (CO 2 ) in glass containers into the deep seabed (confined submarine carbon storage (CSCS)) to cement plants located in four different locations in the world. This technology is based on the bottling of liquid CO 2 at high pressure inside capsules made of glass that are delivered to the bottom of the ocean via a proper pipeline. A Life Cycle Assessment that considers all the stages of the process and 13 impact categories, with a focus on climate change, shows an impact in the four case studies between 0.084 and 0.132 ton of CO 2 equivalent (eq) per ton of CO 2 stored. Since carbonation of cement materials over their life cycle is a significant and growing net sink of CO 2 , the capture and storage of CO 2 emissions generated during the production of cement might lead to negative emissions. A cost analysis was also performed, including the capital costs and the operational costs, even considering the funding structure through financing and equity. The costs of the four case studies are from 16 to 29 $/tCO 2 . Although further work is needed to assess in detail some aspects of the design, the result of this stage of the research allows concluding that the application of the CSCS in cement plants is an interesting option for achieving negative emissions, even if limited due the slowness of CO 2 uptake during the lifetime of cement materials
Alkalinization Scenarios in the Mediterranean Sea for Efficient Removal of Atmospheric CO2 and the Mitigation of Ocean Acidification
Full text linkIt is now widely recognized that in order to reach the target of limiting global warming to well below 2°C above pre-industrial levels (as the objective of the Paris agreement), cutting the carbon emissions even at an unprecedented pace will not be sufficient, but there is the need for development and implementation of active Carbon Dioxide Removal (CDR) strategies. Among the CDR strategies that currently exist, relatively few studies have assessed the mitigation capacity of ocean-based Negative Emission Technologies (NET) and the feasibility of their implementation on a larger scale to support efficient implementation strategies of CDR. This study investigates the case of ocean alkalinization, which has the additional potential of contrasting the ongoing acidification resulting from increased uptake of atmospheric CO2 by the seas. More specifically, we present an analysis of marine alkalinization applied to the Mediterranean Sea taking into consideration the regional characteristics of the basin. Rather than using idealized spatially homogenous scenarios of alkalinization as done in previous studies, which are practically hard to implement, we use a set of numerical simulations of alkalinization based on current shipping routes to quantitatively assess the alkalinization efficiency via a coupled physical-biogeochemical model (NEMO-BFM) for the Mediterranean Sea at 1/16° horizontal resolution (~6 km) under an RCP4.5 scenario over the next decades. Simulations suggest the potential of nearly doubling the carbon-dioxide uptake rate of the Mediterranean Sea after 30 years of alkalinization, and of neutralizing the mean surface acidification trend of the baseline scenario without alkalinization over the same time span. These levels are achieved via two different alkalinization strategies that are technically feasible using the current network of cargo and tanker ships: a first approach applying annual discharge of 200 Mt Ca(OH)2 constant over the alkalinization period and a second approach with gradually increasing discharge proportional to the surface pH trend of the baseline scenario, reaching similar amounts of annual discharge by the end of the alkalinization period. We demonstrate that the latter approach allows to stabilize the mean surface pH at present day values and substantially increase the potential to counteract acidification relative to the alkalinity added, while the carbon uptake efficiency (mole of CO2 absorbed by the ocean per mole of alkalinity added) is only marginally reduced. Nevertheless, significant local alterations of the surface pH persist, calling for an investigation of the physiological and ecological implications of the extent of these alterations to the carbonate system in the short to medium term in order to support a safe, sustainable application of this CDR implementation
The Availability of Limestone and Other Raw Materials for Ocean Alkalinity Enhancement
Full text linkThe work assesses the availability and localizations of different raw materials suitable for ocean alkalinity enhancement (OAE), like limestone, olivine, magnesite and brucite, since several billion tons of rocky materials are needed to achieve meaningful results for carbon sequestration through OAE. Resources of carbonates are immense and widespread around all continents. Availability of pure carbonates is still very large (outcrop area 4.1 million km(2)) and is not a constraint for the large-scale development of OAE. Outcrops of pure carbonates within 10 km from the coastline and below bare ground or scrub/shrub, preferred for the logistics of exploitation, account for about 70,000 km(2), and could provide about 5,000 Gt of limestone. These values increase by a factor of 3 and 8 within 50 and 100 km from the coastline, respectively. Potential resources of olivine, less easily identifiable from the geological data, are estimated in the order of a few hundred billion tons and could provide only a minor contribution to ocean-based carbon removal strategies. A comparison with the current level of world extraction of mineral raw materials is also provided. The annual production of limestone, estimated to be more than 6.6 Gt from deposits scattered all around the world, is about 9% of the world production of mineral raw materials (around 44 Gt yr(-1)), and is of the same order of magnitude as coal (7.3 Gt yr(-1)). The annual productions of magnesite (29 Mt yr(-1)), olivine (8.4 Mt yr(-1)) and brucite (1.5 Mt yr(-1)) are two orders of magnitude lower
Anthropogenic climate change as a monumental niche construction process: background and philosophical aspects
No full textClimate change has historically been an evolutionary determinant for our species, affecting both hominin evolutionary innovations and extinction rates, and the early waves of migration and expansion outside Africa. Today Homo sapiens has turned itself into a major geological force, able to cause a biodiversity crisis comparable to previous mass extinction events, shaping the Earth surface and impacting biogeochemical cycles and the climate at a global level. We argue that anthropogenically-driven climate change must be understood in terms of a monumental niche construction process, generating long-term ecological inheritance and eco-evolutionary feedbacks that are putting our health and well-being and those of future generations at risk. We then list five major sources of climate change counter-intuitiveness, highlighting how evolved cognitive biases and heuristics may stand in the way of providing effective responses within tight deadlines. Drawing on our framing of the climate breakdown, we finally call for an evolutionary perspective in approaching the adaptive challenge posed by climate change: we argue that putting the brakes on a genuine self-endangering evolutionary trap ultimately depends on our counteractive niche constructing abilities, played at the level of our institutional and innovation capacity
- …
