Page 138 - Materials Chemistry, Second Edition

Chapter 10

Climate change responses: carbon offsets, biofuels
and the life cycle assessment contribution

Scott McAlister and Ralph E Horne

Carbon accounting has rapidly gained prominence because of the increasing recognition of the
need to reduce greenhouse gas emissions as a result of evidence from the Intergovernmental
Panel on Climate Change (IPCC 2007a, b, c) and the Stern Review for the British government
(Stern 2006), among other authorities. Any scheme to reduce greenhouse gas emissions in a
systematic way, such as the Kyoto Protocol or regional schemes, requires a standard methodol-
ogy to account for the generation and sequestration of emissions. This is also a requirement for
carbon trading schemes and carbon taxes.
LCA has a solid historical connection with carbon accounting since its past lies at least
partly in energy accounting – and carbon emissions are dominated by the burning of fossil
fuels for primary energy supply. Various attempts have been made to adapt LCA techniques to
calculating the net carbon benefits of offsets and substitution of biomass. Initiatives have
sought to standardise methods and approaches through programs such as the International
Energy Agency (IEA) Task 38 and the European Commission-funded BIOmass-based climate
change MITigation through Renewable Energy (BIOMITRE) project (Horne and Matthews
2004; van Dam et al. 2004).
In this chapter, the practice of carbon accounting is outlined and current controversies are
investigated. A short description of existing standards for carbon accounting is presented,
followed by a review of carbon accounting, life cycle assessment (LCA) and related methods.
The remainder of the discussion focuses on three main case studies. The first is the use of
forestry schemes as carbon offsets to compensate for greenhouse gas emissions associated with
other activities. The second is the use of biomass energy technologies in place of fossil fuel-
based energy technologies. The third illustrates LCA’s potential role in and contributions to
the uptake of carbon accounting.

10.1 Carbon accounting standards and assessment tools
There are two standards commonly used in carbon accounting: the international standard
from the International Organization for Standardization’s (ISO) ISO 14064 (ISO 2006a, b, c),
and the World Resources Institute and World Business Council on Sustainable Development
(WBCSD) ‘Greenhouse Gas Protocol’ (WRI-WBCSD 2004, 2005). ISO 14064 is divided into
three parts, while the Greenhouse Gas Protocol consists primarily of two separate but linked
standards; the first dealing with corporate level accounting and the second for project level
accounting. Both standards are similar in intent and content and are complementary. ISO
14064 is less descriptive and shorter than the Greenhouse Gas Protocol, while the Greenhouse

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