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area in the case of waste) (Boruck et al., 2013). This equation weights the local area, given in
local hectares, into global hectares using conversion figures. The latter vary by product,
country, year, and by type of surface, considering the specific features of each type of surface
and use.
Equation 3. Basic equation for the EF calculation
𝐸𝐹𝑝 = ∑
9:
;<,:
:
× í µí±Œí µí°¹í µí±›, 𝑖 × í µí°¸í µí±„í µí°¹í µí±– Equation 3
Where;
- Pi: Quantity of a primary product i produced, or amount of waste (CO2) emitted
expressed in tonnes (tonne of CO2 equivalent)
- Yn,i : National average yield for product or commodity i,
- YFn,i : Country-specific yield factor for a specific product i,
- EQFi: Equivalence factor specific to a type of bioproductive surface of product i.
Similarly, biocapacity (BC) represents the production potential of a global hectare (Udhe,
2009). It is given by the following formula:
Equation 4. Basic equation for the BC calculation
𝐵𝐶 = ∑ 𝐴𝑖
:
× í µí±Œí µí±›, 𝑖 × í µí°¸í µí±„í µí°¹í µí±–
Equation 4
Where Ai, is the bioproductive area available for the production of each product i at the
country's level expressed in local physical hectare “han”. The terms han (national hectare) and
haw (world hectare) refer to the same unit as "ha". They are physical hectares, used to
distinguish between national and global annual average yields. The diagram (figures 2)
resumes calculation methodology.
1.4.2. Conversion factors and calculation scheme
The main conversion factors in ecological footprint calculations are the Yield and the
Equivalence Factor, defined as follows;
Figure 2. The ecological footprint, Biological capacity and Ecological balance