Life cycle assessment of data centers has indicated that the main environmental impacts stem from the embodied impacts, energy efficiency and source energy mix of the Information Communications Technology (ICT) equipment and facility mechanical and electrical systems. Metrics to describe the in-use efficiency of the power and cooling infrastructure are well adopted, however the other areas often go unmonitored, in part due to lack of data, metrics and difficulty of measurement. Without a holistic view of impact, burden shift may occur, i.e. where action is taken to reduce the environmental impact of one area and results in the impact being moved or increased in another area. Life cycle assessment considers a range of environmental impacts, such as climate change, grouped into damage categories: human health, ecosystem quality, and resources. In this paper a metric comprising separate measures for each main area of impact is described, identifying key variables and analysing their range so that their effect on environmental impact may be understood and used as a basis for decision making. The operational component includes the influence of energy and water consumption, PUE, WUE, and renewable energy usage. The embodied component considers variables such as utilization, equipment lifecycle, materials and disposal for mechanical and electrical systems and plant, and ICT equipment. These are related to the ICT output via a productivity proxy. The paper includes preliminary analysis of the application of the metric.