###### Abstract  
In this study, we analyzed the CO2 emissions of online music and video streaming services, as one of the digital contents, in Japan using life cycle assessment. As a system boundary of online music and video streaming, processes such as data center construction and server manufacturing, usage of communication networks and internet communication technology devices (personal computers (FCs) and smartphones), and disposal of data centers and servers were considered. Data were collected using statistical and online surveys, and CO2 emissions per 1 MB of communication volume were calculated. One of the results revealed that the lifecycle CO2 emissions of listening to online music using PCs and smartphones were \(5.88\times 10^{-4}\) and \(1.43\times 10^{-4}\) kg-CO2/MB, respectively. The overall CO2 emissions for domestic music and video streaming services in 2019 was 921 thousand t-CO2. Online video streaming accounted for \(87.7\%\) of the total emissions, which corresponded to approximately \(0.23\%\) of domestic CO2 emissions derived from electric power generation. life cycle assessment (LCA); internet communication technology (ICT); streaming: music; videos +
Footnote †: journal: Applied  
**Citation:** [PERSON]; [PERSON] Life Cycle Assessment of CO2 Emissions of Online Music and Videos  
Streaming in Japan. _Appl. Sci._**2021**, _11_, 3992. [[https://doi.org/10.3390/app11093992](https://doi.org/10.3390/app11093992)]([https://doi.org/10.3390/app11093992](https://doi.org/10.3390/app11093992))  
Academic Editor: [PERSON]  
Received: 1 April 2021  
Accepted: 27 April 2021  
Published: 28 April 2021  
**Published:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **Note:** **:** **Note:** **:** **:** **:** :** **:** **:** :** :** :** :**:** :** :**:** :**:** :** :**:** :** :**:** :**:** :**: :**: :**: :**:**: :**: :**:**: :**: :**:**: :**:**: :**:**: :**:**: :**: :**:**: :**:**: :**: :for 1% of the annual domestic power consumption in 2015 [6]. Thus, ICT-related energy conservation has become an urgent issue to address. ICT provides various services, and this study focused on online music and video streaming. In recent years, a lifestyle of listening and/or watching music and video streamed from the internet worldwide on PCs and smartphones has been established. According to the Japanese Ministry of Economy, Trade, and Industry [7], the total domestic digital content market in 2018 was USD 97,410 million, of which, online music and videos accounted for 8% and 33%, respectively. By 2023, the digital content market is projected to reach USD 103,678 million [7]. Lifestyle changes accompanied by convenience may be appealing; however, an increase in environmental impact due to such lifestyle changes may not be desirable for a sustainable society. To avoid this, the environmental impact of ICT should be understood such that its promotion can suppress the environmental impact. In this study, we aimed to examine CO\({}_{2}\) emissions associated with online music and video streaming using life cycle assessment (LCA). There are a wide range of fields related to ICT, and many studies have examined the environmental impact of ICT from an environmental aspect; smart cities [8; 9; 10], smart homes and buildings [11; 12; 13; 14], transportation [15; 16; 17; 18], teleworking [19; 20; 21], and ICT equipment [22; 23; 24]. In the field regarding consumer experiments, [PERSON] et al. [25] compared CO\({}_{2}\) emissions from listening to music through Compact Disc (CDs) and online streaming. [PERSON] [26] compared the environmental impacts of packaged and digital versions of video games in the United States of America. [PERSON] et al. [27] and [PERSON] et al. [28] analyzed the GHG emissions of online video streaming in the United States of America and Sweden, respectively. [PERSON] et al. [29] reviewed the implementation of LCA for various ICT-related services.