  Information and communication technologies (ICT) can make existing products
and activities more efficient or substitute them altogether and could thus
become crucial for the mitigation of climate change. In this context,
individual ICT companies, industry organizations and international initiatives
have started to estimate the environmental effects of ICT services. Often such
assessments rely on crude assumptions and methods, yielding inaccurate or even
misleading results. The few existing methodological attempts are too general to
provide guidance to practitioners. The starting points of this paper are i) a
high level standard from the European Telecommunication Standardisation
Institute (ETSI) and the International Telecommunication Union (ITU), and ii)
its suggested enhancements for single service assessment outlined in "A
Methodology for Assessing the Environmental Effects Induced by ICT Services
Part I: Single services" (Part I in short). Building on the assessment of
single services, the current article identifies and addresses shortcomings of
existing methodologies and industry practices with regard to multiple services
assessment. For a collection of services, it addresses the goal and scope
definition, the so far ignored aggregation of effects among several services,
and the allocation between several companies contributing to one or more
services. The article finally brings these considerations together with those
of Part I into a workflow for performing such assessments in practice.
