Samandrag:

Background, aim, and scope
During the last decades, the electronics industry has undergone tremendous changes due to intense research leading to advanced technology development. Multiple life cycle assessment (LCA) studies have been performed on the environmental implications of consumer electronics. The aim of this review is to assess the consistency between different LCA studies for desktop computers, laptop computers, mobile phones and televisions (TVs).

Materials and methods
A literature study was conducted covering some key LCA contributions to the consumer electronics field. The focus is primarily on global warming potential during 100 years (GWP100) efficiency in different life cycle phases and secondarily on primary energy usage/electricity usages which are normalised per year to find inconsistencies.

Results
The life cycle impact assessment GWP100 results for consumer electronics over the years suggest that most studies are of comparable quality; however, some studies are neither coherent nor transparent. Published LCAs for mobile phone and TV sets are consistent, whereas for laptop and desktop computers, the studies occasionally give conflicting messages.

Discussion
The inconsistencies appear to be rooted in subjective choices and different system boundaries and lifetime, rather than lack of standardisation. If included, the amounts of emissions of sulphur hexafluoride (SF6) and nitrogen trifluoride (NF3) are crucial to the GWP100 in the various life cycle phases for a desktop using liquid crystal display (LCD) screen. Another important observation is that the MEEuP methodology report/tool underestimates the GWP100 of electronic component manufacturing processes.

Conclusions
Between 1997 and 2010, the ISO 14040/44 standards have ensured a rather consistent set of GWP100 results for the studied products. However, the lack of transparency for consumer electronics LCAs sometimes makes benchmarking difficult. It is nevertheless possible to compare new LCA calculations to existing studies. It is also possible to reveal which product studies are consistent with studies of submaterials and subcomponents. In most cases, the GWP100 results for consumer electronics are consistent. Based on the survey of published work, recycling and other end-of-life processes have a tiny share of the total GWP100 score for consumer electronics.

Recommendations and perspectives
LCA researchers should as a rule, if possible, make a historical survey of their technical system to establish trends, proportions and relations. Policy makers ought to ask for these surveys when using LCAs for decision support. This charter is necessary as to understand the reasonableness of the results. Additions to the ISO14040/44 LCA standardisation for mass–volume products would be worthwhile as a means of increasing the consistency.