Process Simulations and Experimental Studies of CO2 Capture

Carbon dioxide, whose global emissions into the atmosphere have reached a maximum of about 36 billion tons per year (compared to the 6 billion tons emitted in 1950), is considered by far the main greenhouse gas (GHG) [...]

Prediction of Surface Temperature and CO2 Emission using a novel grey system model

The increase in surface temperature and CO2 emissions are two of the most important issues in climate studies and global warming. The ‘Global Emissions 2021’ report identifies the six biggest contributors to CO2­ emissions; China, USA, India, Russia, Japan, and Germany. The current study projects the increase in surface temperature and the CO­2 emissions of these six countries by 2028. The EGM (1,1,α,θ) grey model is an even form of the model with a first order differential equation, that has one variable and a weightage background value that contains conformable fractional accumulation. The results show that while the CO2 emissions for Japan, Germany, USA and Russia show a downward projection, they are expected to increase in India and remain nearly constant in China by 2028. The surface temperature has been projected to increase at a significant rate in all these countries. By comparing with the EGM (1,1) grey model, the results show that the EGM (1,1, α, θ) model performs better in both in-sample and out-of-sample forecasting. The paper also puts forward some policy suggestions to mitigate, manage and reduce increases in surface temperature as well as CO2 emissions.

Toxicity of Tire Rubber Microplastics to Freshwater Sediment Organisms

High emission of tire rubber particles to the surrounding environment is an inevitable consequence of the current habits of transportation. Although most of the emissions stay within a close range of the sources, it has been proven that the smallest particles can be transported to remote locations through the atmosphere, including inland water bodies. It has been estimated that a relevant portion of the global emissions of tire rubber particles reach surface waters, but effects on aquatic life in the receiving water bodies are not completely understood. In the present study, we used the freshwater sediment dwellers Lumbriculus variegatus and Chironomus riparius to examine the toxicity of tire rubber particles at environmentally relevant concentrations, using different types of sediment and two particle sizes of tire rubber. Overall, the experiments were unable to discern any effects on the growth, survival or reproduction of the two animals tested. Significant differences were found among the animals dwelling on different sediments, but the effects were not attributable to the presence of tire rubber particles. This study provides important information regarding the lack of effect of tire rubber particles in laboratory experiments with model sediment dwellers and opens more questions about the potential effects of tire rubber particles in the real environment with longer durations and varying environmental factors. The influence of other factors such as the leaching of additives in the overall toxicity of tire rubber particles should be also considered.

COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF NOx AND OTHER POLLUTANTS IN THE MAN B&W 7S50MC MARINE ENGINE AND EFFECT OF EGR AND WATER ADDITION

Marine engines represent a significant contribution to global emissions. In order to overcome this problem, a great attention was given to reduce their exhaust emissions in the last years, and marine engines have to adapt to regional, national and international restrictions. In this regard, the purpose of this paper is to develop a numerical model to study NOx (oxides of nitrogen) and other pollutants in engines. EGR and water addition were studied too as measures to reduce NOx. The main advantage of this study is that it provides a cheap and fast method to analyze emissions, contrary to experimental setups which are too expensive and laborious. Particularly, a commercial marine engine was analyzed and validated with experimental data. Results showed that increasing EGR and water addition leads to reduce NOx, but increase carbon monoxide and unburnt hydrocarbons due to an incomplete combustion.

“It’s in Our DNA”: Climate Change and Perceived Resilience and Adaptive Capacity in Nature-Based Tourism in Lofoten, Norway.

In 2018, tourism was the fastest growing sector in the world, accounting for 10 percent of all jobs worldwide and 10.4% of the world’s GDP. Tourism is often cited as a strategy for future development at national, regional, and local levels. This paper takes a closer look at the Lofoten Islands in Northern Norway, where the increase in nature-based tourism over the last two decades has occurred in parallel with the restructuring of the traditional fisheries. Nature-based tourism in rural regions relies heavily on a broad range of ecosystem services (ES). This paper will present how stakeholders in nature-based tourism assess the influence of climate change on ES crucial for their activities and for the destination, and outline and explain how the practitioners perceive their ability to withstand or adapt to these changes. With the aid of models depicting potential future climate scenarios, we initiated discussions with stakeholders and found that tourism actors have only to a minor degree sought to develop strategies to increase adaptive capacity and therefore resilience to climate change. Based on our findings, we discuss how the adaptive capacity of individual actors in nature-based tourism forms the basis for the system’s resilience, and that a general resilience focus also forms the basis for transformational capacity, a capacity needed for future resilience. In light of our findings and analyses, we will conclude by reflecting on overarching systemic transformative tendencies in the wake of COVID-19 and obligations contained in the Paris Agreement on reducing global emissions.

Methane Fluxes of Vegetated Areas in Natural Freshwater Ecosystems: Assessments and Global Significance

Freshwater ecosystems, including wetlands, lakes, and running waters, are estimated to contribute roughly 40% to global emissions of methane (CH4), a highly potent greenhouse gas. The emission of CH4 to the atmosphere entails the diffusive, ebullitive, and plant-mediated pathway. The latter, in particular, has been largely understudied and is neither well understood nor quantified. We have conducted a semi-quantitative literature review to (i) provide a synthesis of the different ways vegetated habitats can influence CH4 dynamics (i.e., production, consumption, and transport) in freshwater ecosystems, (ii) provide an overview of methods applied to study the fluxes from vegetated habitats, and (iii) summarize the existing data on CH4 fluxes associated to different types of vegetated habitats and their range of variation. Finally, we discuss the implications of CH4 fluxes associated with aquatic vegetated habitats for current estimates of aquatic CH4 emissions at the global scale. We identified 13 different aspects in which plants impact CH4 dynamics (three related to gaseous CH4 flux pathways) and ten approaches used to study and quantify fluxes from vegetated habitats. The variability of the fluxes from vegetated areas was very high, varying from -454.4 mg CH4 m-2 d-1 (uptake) to 2882.4 mg CH4 m-2 d-1 (emission). This synthesis highlights the need to incorporate vegetated habitats into CH4 emission budgets from natural freshwater ecosystems and further identifies understudied research aspects and relevant future research directions.

Amazon methane budget derived from multi-year airborne observations highlights regional variations in emissions

Atmospheric methane concentrations were nearly constant between 1999 and 2006, but have been rising since by an average of ~8 ppb per year. Increases in wetland emissions, the largest natural global methane source, may be partly responsible for this rise. The scarcity of in situ atmospheric methane observations in tropical regions may be one source of large disparities between top-down and bottom-up estimates. Here we present 590 lower-troposphere vertical profiles of methane concentration from four sites across Amazonia between 2010 and 2018. We find that Amazonia emits 46.2 ± 10.3 Tg of methane per year (~8% of global emissions) with no temporal trend. Based on carbon monoxide, 17% of the sources are from biomass burning with the remainder (83%) attributable mainly to wetlands. Northwest-central Amazon emissions are nearly aseasonal, consistent with weak precipitation seasonality, while southern emissions are strongly seasonal linked to soil water seasonality. We also find a distinct east-west contrast with large fluxes in the northeast, the cause of which is currently unclear.

Are Cities Taking Center-Stage? The Emerging Role of Urban Communities as “Normative Global Climate Actors”

Cities around the world are playing an increasingly active role in global climate governance. Considering their share in global emissions on the one hand, and the direct threats they face from climate-related disasters on the other, urban communities are at the forefront of mitigation and adaptation actions. While cities generally implement such actions as part of their State’s international climate commitments, they sometimes go beyond, or even against the nationally adopted policy stance. This article explores the evolving normative role of cities in relation to climate change, considering how they can contribute, both to the development of new rules of international law, and to the implementation of existing norms for climate action at the domestic level. Based on an analysis of current developments and concrete examples, the article reflects on the potentialities and constraints of cities as “normative global climate actors”.

Carbon Inequality in 2030: Per capita consumption emissions and the 1.5⁰C goal

The world’s richest 1% are set to have per capita consumption emissions in 2030 that are still 30 times higher than the global per capita level compatible with the 1.5⁰C goal of the Paris Agreement, while the footprints of the poorest half of the world population are set to remain several times below that level. By 2030, the richest 1% are on course for an even greater share of total global emissions than when the Paris Agreement was signed. Tackling extreme inequality and targeting the excessive emissions linked to the consumption and investments of the world’s richest people is vital to keeping the 1.5⁰C Paris goal alive.