Page 36 - Materials Chemistry, Second Edition

22 E. I. Wiloso and R. Heijungs

In agricultural land use, there are three time periods in examining the long-term
consequences of agricultural activities, i.e., the period before (transformation),
during (occupation), and after (restoration) agriculture (Mila i Canals et al. 2007).
Based on these time frames, one may refer to land use as an activity during the
occupation period and land-use change as land transformation or a change in the
properties of the land surface area. This could be a new type of land use at a single
point in time such as deforestation or agricultural expansion (Mila i Canals et al.
2007). Similarly, IPCC refers to land-use change as land conversion but also,
interestingly, as changes in carbon pools without land conversion (IPCC 2001). In
fact, the precise place of land use and land-use change in the LCA framework is
not clear. For example, besides as an activity, land use can also be an inventory
item, just like CO 2 (certain land area occupied for certain period of time). Addi-
tionally, land-use change can be an activity (a unit process, e.g., clearing of forest)
(Heijungs et al. 1992). Even impacts of land use or land-use change are frequently
indicated simply with the term land use.
Mitigating the competition for land can only be established if the complexity of
the competition dynamics is fully addressed. Each of the contributing factors
(energy, food, feed, and fiber demand) cannot be treated in isolation (Harvey and
Pilgrim 2011). All these factors are intimately interconnected, particularly in
large-scale development of bioenergy (McKone et al. 2011). Although the com-
petition of land used for food, fiber, and energy was recognized a long time ago,
quantification attempts involving competition aspects have been made only quite
recently (Searchinger et al. 2008). Drivers for increased bioenergy use (e.g., policy
targets for renewables) can lead to increased demand for biomass, leading to
competition for land currently used for food production and, possibly, indirectly
causing new and sensitive areas to be converted into arable land (IEA-Bioenergy
2009). These interconnected factors in the complexity of direct and indirect land
use are previously illustrated in Fig. 1, while activities, resource use, and emis-
sions typically involved in land use and land-use change are shown in Fig. 2.

Land clearing • Land
Tillage transformation CO 2
Seeds N 2O
Planting • Cultivation and CH 4
Irrigation harvesting of Nutrient
Water energy crops Toxics
Fertilizer Harvested biomass
Pesticides • Removal of Removed biomass
Biomass harvesting biomass residues
Biomass collection from soil

Fig. 2 Inventory of activities, resource use, and emissions in the agricultural chain of biomass
feedstock