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Highlights • The internal relationship between decoupling theory and EKC hypothesis was studied. • A two-dimensional decoupling theory was established. • China and US were taken as a case to study. Abstract The current decoupling theory cannot distinguish the decoupling state of a region with different economic development level. To overcome this problem, this paper first studies the internal relationship between decoupling theory and EKC hypothesis. Furthermore, we establish a two-dimensional decoupling theory of economic development and CO 2 emissions. Finally, taking China and US as a case, this theory is used to explore the decoupling relationship between economic development and CO 2 emissions over the period 1965–2016. If the EKC curve satisfies the inverted U type characteristic, the critical point between strong decoupling and weak decoupling can be approximately obtained at the extreme point of EKC curve. Based on the Tapio decoupling theory and extreme point of EKC curve, the two-dimensional decoupling model with 16 kinds of decoupling sates is established. For China and the United States, the EKC curve of carbon emissions and per capita GDP satisfies the inverted U type characteristic. The threshold value of per capita GDP for China and the United States are $7999.5 and $50980.52, respectively. At present, China's economy is experiencing a low level of economic development. The development of the United States in 2014–2015 and 2015–2016 presented strong decoupling with high level of economic development. [ABSTRACT FROM AUTHOR]

Abstract: The rapid growth of energy consumption in conjunction with economic development during past decades in East Asia, especially China, caused severe air pollution problems at local and regional scales. Understanding of the meteorological conditions for air pollution is essential to the understanding of the formation mechanism of air pollutants and the development of effective emission control strategies to reduce air pollution. In this paper, the Fifth Generation National Center for Atmospheric Research (NCAR)/Pennsylvania State University (PSU) Mesoscale Model (MM5) modeling system is applied to simulate meteorological fields during selected six 1-month periods in 2007/2008 over a triple-nested modeling domain covering East Asia, the eastern China, and Shandong Province at horizontal grid resolutions of 36-, 12-, and 4-km, respectively. MM5 generally reproduces well the observations in the eastern China but performs worse in the western China and northeastern China. Largest biases occur in 2-m temperatures (T2) and wind speed and wind direction at 10-m in haze months (i.e., winter) and daily mean precipitation (Precip) in non-haze months (i.e., summer), due to limitations of the model in simulating snow cover and convective precipitation. Meteorological predictions agree more closely with observations at urban sites than those at the coastal and mountain sites where the model performance deteriorates because of complex terrains, influences of urban heat island effect and land/sea breezes, and higher elevations. Model results at 12-km in Shandong Province show an overall better performance than those at 4- or 36-km while the results at 4-km show worst performance due to inaccurate land use and the model’s incapability in simulating meteorological processes at a fine scale. [Copyright &y& Elsevier]

The rise of China is seen by some observers as a precursor of inevitable hegemonic competition in East Asia. At the very least, it seems likely that China's influence in East Asia will grow at the expense of the United States. Whether this will eventually amount to a form of hegemonic transition is far less clear. It is, therefore, an opportune moment to consider the relative strengths and weaknesses of China and the US in East Asia. This paper suggests that the nature of hegemonic competition and transition is more uncertain and complex than some of the most influential theoretical understandings of hegemony would have us believe. [ABSTRACT FROM AUTHOR]