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Abstract: This paper assesses the global emission reduction target of halving CO2 emissions by 2050. First, future GDPs with specific uncertainty ranges were developed. The Kaya identity and the developed GDP outlook indicate that halving global CO2 emissions by 2050, which corresponds to almost 450 ppm-CO2eq. stabilization, requires an improvement approximately four times as large as the historical CO2 intensity improvement rate on average up to 2050, if GDP loss should remain within a few percent of potential baseline GDP. In addition, the global energy-related CO2 emission reductions were assessed by using an energy systems model. Marginal abatement cost of CO2 is over 470 $/tCO2 for halving global CO2 emissions by 2050 relative to 2005 even under the lower GDP scenario and technology improvements. Great challenges will have to be met for achieving the 450 ppm-CO2eq. Realistic alternative emission reduction scenarios should be explored in two ways; 1) more innovative technological development than any present imaginable development, and/or drastic social innovations are needed for cheaper carbon costs, e.g., within a few tens of US$ per tonne of CO2, and 2) more modest emission reduction targets, e.g., 550 ppm-CO2eq., and adaptation measures are considered. [Copyright &y& Elsevier]

Many of the numerous difficult issues facing the world today involve relationships entailing trade-offs and synergies. This study quantitatively assesses some alternative scenarios using integrated assessment models, and provides several indicators relating to sustainable development and climate change, such as indicators of income (per capita GDP), poverty, water stress, food access, sustainable energy use, energy security, and ocean acidification, with high consistencies among the indicators within a scenario. According to the analyses, economic growth helps improve many of the indicators for sustainable development. On the other hand, climate change will induce some severe impacts such as ocean acidification under a non-climate intervention scenario (baseline scenario). Deep emission reductions, such as to 2° C above the pre-industrial level, could cause some sustainable development indicators to worsen. There are complex trade-offs between climate change mitigation levels and several sustainable development indicators. A delicately balanced approach to economic growth will be necessary for sustainable development and responses to climate change. [ABSTRACT FROM AUTHOR]

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In this study, cost-effective technological options to stabilize CO2 concentrations at 550, 500, and 450 ppmv are evaluated using a world energy systems model of linear programming with a high regional resolution. This model treats technological change endogenously for wind power, photovoltaics, and fuel-cell vehicles, which are technologies of mass production and are considered to follow the "learning by doing" process. Technological changes induced by climate policies are evaluated by maintaining the technological changes at the levels of the base case wherein there is no climate policy. The results achieved through model analyses include 1) cost-effective technological portfolios, including carbon capture and storage, marginal CO2 reduction costs, and increases in energy system cost for three levels of stabilization and 2) the effect of the induced technological change on the above mentioned factors. A sensitivity analysis is conducted with respect to the learning rate. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this paper is to address the question of what would be the real impact of energy efficiency improvements on the reduction of GHG (greenhouse gas) emissions through the deployment of energy-efficient technologies. We study the cost effectiveness of replacing current appliances with more efficient models, taking into consideration the implicit discount rate observed in people’s purchasing behavior. This is followed by a discussion of why the efficiency gap exists and how large it is. If the world were to successfully implement every negative- or zero-cost measure, the CO2 abatement potential in the global residential and commercial sector in 2020, on a conservative estimate, would be 1.4 Gt of CO2, roughly equivalent to the current CO2 emissions of India as the world fourth largest emitter. If a longer payback period is allowed, a further 1.2 Gt of opportunities, which almost amount to the current CO2 emissions of Japan as the world’s fifth largest emitter of CO2, could be gained globally at below zero-cost in 2020. [Copyright &y& Elsevier]

Acute onset of organ failure in heatstroke is triggered by rhabdomyolysis of skeletal muscle. Here, we showed that elevated temperature increases free cytosolic Ca 2+ [Ca 2+ ]f from RYR (ryanodine receptor)/UNC-68 in vivo in the muscles of an experimental model animal, the nematode Caenorhabditis elegans This subsequently leads to mitochondrial fragmentation and dysfunction, and breakdown of myofilaments similar to rhabdomyolysis. In addition, treatment with an inhibitor of RYR (dantrolene) or activation of FoxO (Forkhead box O)/DAF-16 is effective against heat-induced muscle damage. Acute onset of organ failure in heatstroke is triggered by rhabdomyolysis of skeletal muscle. To gain insight into heat-induced muscle breakdown, we investigated alterations of Ca 2+ homeostasis and mitochondrial morphology in vivo in body-wall muscles of C. elegans exposed to elevated temperature. Heat stress for 3 hr at 35° increased the concentration of [Ca 2+ ]f, and led to mitochondrial fragmentation and subsequent dysfunction in the muscle cells. A similar mitochondrial fragmentation phenotype is induced in the absence of heat stress by treatment with a calcium ionophore, ionomycin. Mutation of the unc-68 gene, which encodes the ryanodine receptor that is linked to Ca 2+ release from the sarcoplasmic reticulum, could suppress the mitochondrial dysfunction, muscle degeneration, and reduced mobility and life span induced by heat stress. In addition, in a daf-2 mutant, in which the DAF-16/FoxO transcription factor is activated, resistance to calcium overload, mitochondrial fragmentation, and dysfunction was observed. These findings reveal that heat-induced Ca 2+ accumulation causes mitochondrial damage and consequently induces muscle breakdown., (Copyright © 2017 Momma et al.)