LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

PARALLEL SESSION 3A: LAND USE CHANGE 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
changes for each time series (Figure 1). Final estimations of land use changes areas, used for the methodology
Agri-BALYSE are provided in Table 2.
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9
1980 1990 2000 2010
1980 1990 2000 2010
Figure 1. Cropland and grassland areas from 1981 – 2010, before and after correction.
Table 2. Twenty-year matrix of land use changes areas between permanent grasslands and annual crops for
mainland France during the period 1990-2010, based on UNFCCC (CITEPA, 2012).
Land-use changes Area (ha/year)
Annual crops becoming permanent grassland 118,158
Permanent grassland becoming annual crops 159,732
2.2. Simplified method to estimate soil C dynamics from LUC
We first calculate soil C stocks for permanent grasslands and annual crops. The data from the French Soil
Survey Network (Martin et al., 2011), allowed the calculation of an average soil C stock for both types of
land use. This was done at national scale (Table 3), these averages obviously integrate a significant variability.
Table 3. National average soil C stocks for permanent grassland and annual crops based on the French Soil
Survey Network.
Land-Use Average Soil C Stock (tC/ha)
Permanent grassland 72.7
Annual crops 53.3
∆ Grassland, Annual crop 19.4
Then, the land use data from the French UNFCCC NIR (CITEPA, 2012) allowed us to determine areas
having undergone LUC less than 20 years ago for each year of the Agri-BALYSE reference period: 2005-
2009.
The next step of the method is to determine, for each year of the reference period, annual soil C storage/emissions
for areas having undergone LUC. The calculations have been done for each year of the reference
period. This results in an emission factor for CO2 from LUC expressed per ha of permanent grassland
having undergone LUC (EFGrass_LUC -3.16 t CO2/ha) and a similar factor expressed per ha of annual crop (EF-
Crop_LUC 3.40 t CO2/ha), for each year of the 2005-2009 period.
An emission factor for permanent grasslands and annual crops, considering all areas of both land uses, including
those that did not undergo LUC, is then calculated through Equations 1 and 2 from 2005 to 2009:
Grassland/annual crop area in ha
EFGrass_Tot: Emission factor for CO2 from LUC expressed per total area of permanent grassland (tC/ha)
EFGrass_LUC: Emission factor for CO2 from LUC expressed per area of permanent grassland having undergone LUC (tC/ha)
EFCrop_Tot: Emission factor for CO2 from LUC expressed per total area of annual crop (tC/ha)
EFCrop_LUC: Emission factor for CO2 from LUC expressed per area of annual crop having undergone LUC (tC/ha)
270
Million ha
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Croplands
Raw data
Corrected data
Million ha
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12
11
10
Grasslands
Raw data
Corrected data
Eq. 1
Eq. 2