Environmental Engineering Reference
In-Depth Information
Graedel and Allenby, 2010). In the “paper versus plastic bag” debate,
individual impacts such as “litter reduction,” “no threat to animal life via
entanglement,” or “use of renewable resources” clearly favor single-use
degradable paper bags over the plastic bags. But in terms of other attributes
such as “energy use,” “water use during manufacture,” or “greenhouse gas
relative importance of the different impacts in the analyst that determine
how these multiple impacts might be synthesized into a meaningful metric.
Carrying out LCA assessment in practice is considerably simplified by
available software. The most used LCA software packages globally (Cooper
and Fava, 2006) at the present time are GaBi and SimaPro. Others such
as Sustainable Minds (
www.sustainableminds.com
)
or Compass
(
http://www.greenerpackage.com
)
support product design exercises. Using
different LCA tools (software) can also yield inconsistent findings. Ranking
of the environmental merits of four types of diapers using three different
LCA tools yielded very different rankings (the lowest ranked diaper in one
assessment was in fact found to be the best in another!) (Simon et al., 2012).
LCAcannotbeusedtofindoutwhichproductis“greener”inabsoluteterms;
it can at best only compare individual impacts related to two comparable
products.
Even with the best available inventory data, very good software, and
conscientious analysis, LCA can still yield inconsistent conclusions on
environmental impact (Lenzen, 2000), and the best quantitative estimates
have an error of at least ±10%. Despite these limitations, LCA can be a
valuable tool to identify and compare products and processes that have
critical environmental impacts and guide the inevitable changes to make
these sustainable.
2.5 THE EMERGING PARADIGM AND THE PLASTICS
INDUSTRY
While the general directions of the needed changes are fairly easy to
envision, articulating these in concrete practical terms to plan for their
implementation is more difficult. What is particularly useful is a simple
means of determining if a proposed change in business practice has value
in terms of environmental sustainability. If a methodology that classifies
