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The United States Environmental Protection Agency (EPA) requires that some institutional organizations (corporations, government entities, NGOs, universities, and so forth) report annually the amount of different greenhouse-gas (GHG) emissions generated. The organizations are to select and utilize various EPA equations for calculating various kinds of GHG emissions. That database is then available to plan for climate-change mitigation. The simplistic linear production functions expressed in the equations, along with exemptions, allows for the totals reported by EPA for carbon dioxide, methane, and the other GHG emissions to be significantly understated. Although understated, that database is utilized by various agencies of government in the United States for policy mitigation and in negotiations with other countries. Because meaningful climate-change mitigation policy requires accurate measurement, the purpose here is the analysis and critique of EPA equations for reporting greenhouse-gas emissions and to offer advice about what EPA ought to be doing. [ABSTRACT FROM AUTHOR]

Sweet potato (Ipomoea batatas L.) is a promising food and industrial crop that plays an important role in China's agricultural poverty relief strategy. Selecting an appropriate cropping system for sweet-potato production could simultaneously achieve energy, economic, and environmental benefits. Therefore, the comprehensive assessment of diversified sweet-potato-based cropping systems (i.e., sweet potato monoculture (SP), continuous sweet potato cropping (SPSP), sweet potato–rice (SPRI), sweet potato–maize (SPMA), and sweet potato–potato (SPPO)) in South China was conducted with a field survey and life-cycle assessment. The data were collected quantitatively using a questionnaire for face-to-face interviewing of 70 farmers. The results indicated that the annual crop yield (sweet potato equivalent yield) of five cropping systems was in increasing order as SPPO > SPSP > SPMA > SPRI > SP. The SPMA system exhibited the highest net energy (499.09 GJ/ha) and energy rate (7.77). The SPSP system performed better in energy efficiency (0.90 kg/MJ), net return (140,284 CNY/ha), benefit to cost rate (3.20), and eco-efficiency (45 CNY/kg CO2-eq). The annual greenhouse-gas (GHG) emissions of five cropping systems ranked from lowest to highest as follows: SP < SPRI < SPSP < SPMA < SPPO. With comprehensive consideration, extended rotation systems (e.g., SPMA, SPRI, and SPSP) are proposed because they could effectively reduce GHG emissions while maintaining or even increasing the system's productivity (ensuring food safety) in South China. [ABSTRACT FROM AUTHOR]

This article explains the need to integrate the concepts of (a) zero greenhouse-gas (GHG) emissions, (b) the precautionary principle, and (c) environmental impact statements (EISs) to improve climate change mitigation. Across the United States, governments and corporations are adopting positions with the intent to reach zero GHG emissions in some specified year. The first section of this article clarifies how GHG emitting and carbon removing technologies are involved in the concept of net zero GHG emissions. Following that is a discussion of the precautionary principle that needs to be adopted for climate change mitigation. The precautionary principle originated when it became understood that scientific proof of the causes and extent of harmful environmental damage was often not possible until after it was too late to prevent the damage. In turn, analysis should be carried into EISs, which are documents that specify the impact of proposed projects on the environment. EISs are required reports mandated by the National Environmental Policy Act of 1969 to assess the potential impact of actions affecting the quality of the human environment. [ABSTRACT FROM AUTHOR]

As an important trend in the automotive industry, electrification of propulsion systems has potential to significantly reduce greenhouse-gas emissions of the transportation sector. Whereas electric vehicles do not produce exhaust emissions during driving, the impact of electricity provision for charging batteries, as well as the impact of vehicle production play an essential role in a holistic consideration of the carbon footprint. The paper introduces a comprehensive evaluation of greenhouse gas-emission-related factors of cars driven by different propulsion technologies, considering the entire product life cycle. This comprises vehicle production, including battery system, electric powertrain and other relevant components, the car's use phase under consideration of different electricity mixes and the end-of-life phase. The results of the study give insights of influencing factors on life-cycle-related carbon-dioxide-equivalent emissions of cars driven by combustion engines, hybrid powertrains and battery-electric propulsion systems. In addition, a comparison of actual mass-production cars is made and the total life-cycle carbon footprints are discussed under different boundary conditions of electric power supply. In this way, the article comprehensively introduces an automotive life-cycle assessment and provides fundamental information, contributing to an objective discussion of different propulsion technologies. [ABSTRACT FROM AUTHOR]

The aims of this work are to analyze the changes in the world power industry during the time after the adoption of the United Nations Framework Convention on Climate Change of 1992 and to assess the extent to which the commitments of the Kyoto Protocol of 1997 have been met and evaluate the prospects of implementing the tasks of the Paris Agreement of 2015. Based on data on the production and consumption of various kinds of energy and the emissions of greenhouse gases, primarily carbon dioxide, in 1990–2017, changes in the structure of the global energy consumption, trends in electric power generation, and the influence of different factors on the carbon dioxide emissions in power-generating enterprises are investigated. It is shown that the power industry, which is the main source of anthropogenic greenhouse gases (GHGs), is the most inertial branch of the economy in terms of its contribution to the reduction in GHG emissions. Thus, in the first 2008–2012 commitment period of the Kyoto Protocol, GHG emissions in the state parties to the protocol decreased by 7.6% compared the base year, while other GHG sources reduced the emission by 18%. The corresponding figures for the following 2013–2017 commitment period were 10.6 and 17.1%, respectively. The maximum reduction in the carbon dioxide emissions in the power industry resulted from an increase in the global average efficiency of the thermal power stations from 32% in 1990 to 36% in 2017; as a consequence, the cumulative decrease in the CO2 emissions in the world during the 1990–2017 period was approximately 22 billion t. The increase in the electric power generation at HPPs and NPPs resulted in a reduction in GHG emissions by 16.7 and 10.7 billion t, respectively. The substitution of coal and fuel oil by gas at thermal power stations facilitated reducing the emissions by 5.2 billion t, while the use of renewable energy sources for generation of electric energy resulted in a reduction of 1.1 billion t. The contribution of the carbon capture and storage technologies amounting to only 0.2 billion t is not noticeable so far. [ABSTRACT FROM AUTHOR]

One of the current topical problems is the prediction of climate change and mitigation of its consequences. All-sided analysis of ecological, economic, and social aspects of climate issues relies on interdisciplinary assessment models. This article adapts the MERGE optimization model to the current state of the world economy and introduces into the model a new component that implements a simplified procedure of 'green' GDP calculation ('green' GDP, or GGDP, provides information about the efficiency of use of environmental resources). The objective of our numerical simulations is to tests the consequences of Russia's hypothetical participation in the program for reducing greenhouse gas (GHG) emissions and to analyze the environmental indicators of Russia's GDP. The input data are mainly provided by the project of scenario conditions and main macroeconomic parameters for the forecasting of socio-economic development in Russia in the near future implemented by the Ministry of Economic Development of the Russian Federation. The calculations reveal the existence of reserves for Russia's 'painless' participation in environment-preserving initiatives that call for not exceeding the 1990 emission level in 2020-2025. At the same time, increasing the environmental efficiency of Russia's GDP is a relevant task that requires immediate attention. [ABSTRACT FROM AUTHOR]

Shallow lakes, the most prevalent type of freshwater ecosystems, can shift between clear states with macrophyte dominance and turbid, phytoplankton-dominated states. Such transformations, commonly termed regime shifts, have gained increasing attention in recent decades. Of 1084 studies documenting regime shifts, only 28% investigated the consequences for ecosystem functions and services such as habitat (13%), carbon processing (4%), or nutrient retention (4%). Although there is general consensus that a clear macrophyte state supports a higher diversity of aquatic organisms than a turbid one, the effects of shifts on primary production, carbon burial, greenhouse-gas emissions, and nutrient retention remain ambiguous. Shifts between the two states also affect drinking-water quality and the recreational value of lakes, leading to conflicting management measures and potentially deteriorating natural functions. We call for more comprehensive studies on the effects of regime shifts on ecosystem functions in shallow lakes to guide their sustainable management. [ABSTRACT FROM AUTHOR]

As Internet traffic grows, current core network technologies will raise issues in terms of energy consumption. Here, the authors propose three possible optical network architectures for the next-generation Internet core, including an all-optical hybrid optical switching (HOS) network, an optical/electronic HOS network, and an all-electronic switching network. They evaluate and compare all three networks with regard to performance and power consumption via an event-driven simulator. [ABSTRACT FROM PUBLISHER]

Merck suppressed data on harmful effects of its drug Vioxx, and Guidant suppressed data on electrical flaws in one of its heart-defibrillator models. Both cases reveal how financial conflicts of interest can skew biomedical research. Such conflicts also occur in electric-utility-related research. Attempting to show that increased atomic energy can help address climate change, some industry advocates claim nuclear power is an inexpensive way to generate low-carbon electricity. Surveying 30 recent nuclear analyses, this paper shows that industry-funded studies appear to fall into conflicts of interest and to illegitimately trim cost data in several main ways. They exclude costs of full-liability insurance, underestimate interest rates and construction times by using 'overnight' costs, and overestimate load factors and reactor lifetimes. If these trimmed costs are included, nuclear-generated electricity can be shown roughly 6 times more expensive than most studies claim. After answering four objections, the paper concludes that, although there may be reasons to use reactors to address climate change, economics does not appear to be one of them. [ABSTRACT FROM AUTHOR]

Ethics requires good science. Many scientists, government leaders, and industry representatives support tripling of global-nuclear-energy capacity on the grounds that nuclear fission is “carbon free” and “releases no greenhouse gases.” However, such claims are scientifically questionable (and thus likely to lead to ethically questionable energy choices) for at least 3 reasons. (i) They rely on trimming the data on nuclear greenhouse-gas emissions (GHGE), perhaps in part because flawed Kyoto Protocol conventions require no full nuclear-fuel-cycle assessment of carbon content. (ii) They underestimate nuclear-fuel-cycle releases by erroneously assuming that mostly high-grade uranium ore, with much lower emissions, is used. (iii) They inconsistently compare nuclear-related GHGE only to those from fossil fuels, rather than to those from the best GHG-avoiding energy technologies. Once scientists take account of (i)–(iii), it is possible to show that although the nuclear fuel cycle releases (per kWh) much fewer GHG than coal and oil, nevertheless it releases far more GHG than wind and solar-photovoltaic. Although there may be other, ethical, reasons to support nuclear tripling, reducing or avoiding GHG does not appear to be one of them. [ABSTRACT FROM AUTHOR]

This article examines the efficacy of national climate programmes (packages of policies introduced by governments to meet emissions reduction targets set out in the Kyoto Protocol) by considering emissions trends before and after their implementation. Analysis reveals that only four of 21 countries with defined programmes demonstrate improved emissions trends following their inception and in only one is the change statistically significant. The reasons for this are manifold but serendipity appears to play as large a part as strategy in determining national emissions trends in the early years of climate programmes. Inflated claims of success by national governments are unhelpful for effective policy analysis and development. [ABSTRACT FROM AUTHOR]

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