Saving energy and reducing emission is a global topic. China has reduced carbon emission through boosting research inputs, improving energy structure and reaching industrial upgrade. Although China's high pollution industries have spent lots on research, direction and intensity of improving the overall industrial environmental effect from limiting carbon dioxide emission still lacks of concrete indicators. This paper, aiming at effect of research inputs on carbon emission, decomposes LMDI model which has been incorporated with research size effect as a factor of carbon emission, and discusses the decomposition from economic size, research size, energy structure and intensity. STIRPAT model, in order to compensate the LMDI model in flexibility, is used to further study the topic by using overall energy intensity index and research input efficiency, combined with provincial panel data. Increment of research input has little constraints on carbon emission, but improvement of research efficiency and industrial structural upgrade do. Energy structure and energy intensity are outstandingly negatively related to carbon emission. Implementation of conversion of old-new kinetic energy key projects effectively constrains carbon emission. This paper presents suggestions according to the modeling results on targeting research input, increasing research input efficiency, issuing saving power and reducing emission policies, encouraging innovation, promoting the conversion of old-new kinetic energy and optimizing industrial structure.

Environmental taxation is vital means for environmental issues. All nations, developed or developing, actively enforce environmental taxation. This paper uses bibliometric method to visualize the research advances, popular points, and network evolution regarding environmental taxation via Citespace 5.5.R2 from 2799 environmental taxation papers during 2000 to 2019 among Web of Science, CNKI database. American scholars have made outstanding achievements, Dutch and Swiss scholars are readily for international exchanges, but Chinese scholars are largely isolated, lack of global exchanges even internal cooperation, resulting in low quality papers in China. Foreign highly cited papers are largely focused on cases and carbon taxation, while internal on references of foreign taxation on China, theoretically, with absence of empirical studies. Scholars globally study largely on environmental taxation effect, design and optimization with different focuses. In recent two decades, Chinese scholars have a clear research network at four stages. Foreign researchers have formed an entire research system with alternative key words. This paper summarizes the deficiency of Chinese scholars and presents outlook for future studies, aiming at providing references for boosting environmental taxation research for Chinese.