Climate change impacts acidification

The inventory results should be presented in clear form, how much and what substances from the environment enter the system and how much get out. These results serve for subsequent life cycle impact assessment [48], The aim of the life cycle impact assessment is to measurably compare the environmental impacts of product systems and to compare their severity with new quantifiable variables identified as impact category. The impact categories are areas of specific environmental problems such as global warming, climate changes, acidification, eutrophication, ecotoxicity and others. Already in the phase of definition of the LCA study scope, it is necessary to describe what impact category will be applied and which of their environmental mechanisms will serve as a basis for impact assessment [46],... 

As mentioned above, there are characterization factors for a number of different impact categories, e.g. acidification, eutrophication, climate change, human toxicity and ecotoxicity. However, characterization factors are missing for many additives, especially for human toxicity and ecotoxicity, which makes it difficult to assess the potential impact that a product will cause during its entire life cycle. A major reason that characterization factors are often missing is the lack of data regarding substance properties, such as physical chemical properties and toxicity. 

Clean air is an important prerequisite for sustainable development and is a basic requirement for human health and welfare. In addition, air pollutants contribute to atmospheric problems such as acidification and global climate change, which have impacts on crop productivity, forest growth, biodiversity, buildings, and cultural monuments. The benefits from the progress made in the areas of waste gas treatment and environmental legislation are partially offset by industrialization, an increase in the number of private cars in use, and overpopulation. 

Exhaustion of abiotic resources Land surface occupation Climate change Destraction of stratospheric ozone layer Human toxicity Eco-toxicity Formation of photo-oxidants Acidification Eutrophication Loss of biodiversity Impacts of ionizing irradiations Odors SmeUs Drying out... 

When the impact of process scale is viewed from the planetary boundaries perspective, the inherent multicriteria nature of any sustainability assessment is indispensable. Even when only environmental LCA impacts are accounted for, studies have shown that certain boundaries have been crossed or are very close to the limit (i.e., with respect to climate change, biodiversity loss, and nitrogen and phosphorous cycles), while others are stiU reasonably well safeguarded (i.e., stratospheric ozone depletion, ocean acidification, and freshwater use) [64]. It is therefore possible that different production sectors may have an impact on different planetary boundaries some of which may be within or already outside their safe operating space. For instance, studies have indicated the severe impacts of plastic debris on marine organisms [65]. Thus, from a cradle-to-grave LCA perspective, fossil-based plastics production may have a more direct or at least a different kind of effect in terms of biodiversity compared to fossil-based fuel production, which is certainly in higher production scales. 

In this study the ReCiPe methodology (Goedkoop et al., 2008) [3] was adopted. The following midpoint impact categories are included climate change, ozone depletion, human toxicity, photochemical oxidant, particulate matter formation, ionizing radiation, acidification, freshwater eutrophication, marine eutrophication, terrestrial ecotoxicity. 

Life cycle assessment (LCA) is a methodological framework for estimating and assessing the environmental impacts attributable to the life cycle of a product, such as climate change, stratospheric ozone depletion, tropospheric ozone (smog) creation, eutrophication, acidification, toxicological stress on human health and ecosystems, the depletion of resources, water use, land use, noise, and others [3,4]. 

Much attention has been paid to resource use and waste and the associated environmental impacts for the fuel production life cycle. For fuel cells, this notably includes hydrogen but is certainly applicable to all fuel cell fuels. For example, Cooper et al. (2009) present data for the estimation of life cycle energy consumption (total and as fossil, coal, natural gas and petroleum fuels), the contribution to climate change, smog formation, acidification and particulate matter emissions for stationary fuel cell fuels. In fact, they estimate the contribution to climate change of the fuel production life cycle for various hydrogen sources, liquid petroleum gas and natural gas from 38.3 to 1430 kg CO2/MJ. 

Most LCAs are performed only xmtil Step 2, since impact assessment and interpretation involve many more qualitative assumptions. In this case, LCA are called life cycle inventories (LCIs). This latter is a tool required to estimate the direct and indirect inputs of each step of a biofuel pathway. The results are the use of resources (eg, energy consumption) and the environmental emissions (eg, CO2, sulfur oxides, nitrogen oxides). LCIs permit the assessment of impact categories, such as climate change, photooxidant formation, acidification, eutrophication, ecotoxicity and human toxicity, and the depletion of biotic and abiotic resources. These factors of the LCI will be converted into environmental damages. Various indicators can be derived from these mechanisms at intermediate levels (midpoints) or damage levels (endpoints) after normalization, often weighting approaches. 

In the near future we anticipate further progress in ocean acidification as a result of increased atmospheric CO2 concentrations (Caldeira and Wickett, 2003) with sea surface pH potentially reaching as low as 7.8, a decrease of 0.5 pH units since the middle of the 20th century. More extensive periods of stratification and a spreading of oxygen-minimum zones in the world s oceans are also expected. Each of these processes is likely to impact on the oceanic N-cycle and the role cyanobacteria play within these systems. Specifically, these climate induced changes are likely to have significant effects on the composition of marine cyanobacterial communities and hence on the N dynamics they carry out. 

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