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Page 10 of 22 François et al. Carbon Footprints 2026, 5, 22

Figure 3. Delay factors for GWP as a function of the lifetimes of GHGs and for a single emission t i = LCD with THI = 100 years. GHG:
Greenhouse gases; LCD: life cycle duration; THI: time horizon of the impact; GWP: global warming potential.

Table 1. Delay factors for GWP for the 11 main GHG and for a single emission t i = LCD with THI = 100 years

Alpha factor Alpha factor Alpha factor (LCD Alpha factor Alpha factor (LCD
GHG Lifetime
(LCD = 10 yrs) (LCD = 25 yrs) = 50 yrs) (LCD = 100 yrs) = 200 yrs)
Combined 0.928 0.84 0.728 0.581 0.432
CO 2
CH 4 with oxidation 11.8 0.994 0.986 0.972 0.948 0.907
N 2 O 109 0.945 0.88 0.803 0.715 0.641
HFC-134a 14 1 0.999 0.999 0.999 0.999
HFC-125 30 0.99 0.98 0.971 0.966 0.964
1000 0.914 0.81 0.683 0.525 0.367
SF 6
PFC-14 50000 0.909 0.8 0.667 0.5 0.334
CFC-11 52 0.971 0.939 0.904 0.872 0.857
CFC-12 102 0.947 0.885 0.811 0.727 0.66
HCFC-22 11.9 1 1 1 1 1
32 0.988 0.976 0.965 0.958 0.956
CCl 4
GWP: Global warming potential; GHG: greenhouse gases; LCD: life cycle duration; THI: time horizon of the impact.

indicator. Nonetheless, increasing the LCD period decrease the slope of delay factors, then delayed emissions
occurring before LCD will have less favorable delay factors than with a shorter LCD.

Delay factor β for global temperature potential characterization factor
As defined before, the mathematical expression of the delay factor β associated to the GTP indicators for a
given observation time T is:

6C? 8, 9 ()) (22)
V 8, 9 ()) =
)% 9 ())
Similarly to the delay factor α [Equation 20], Equation 22 can be rewritten by replacing the expression of
Equations 5 and 18, while considering the relationship agtp (T) = AGTP(T):
0,j
j
06C ? 8, 9 ())
V 8, 9 ()) =
06C ? 0, 9 ())
∫ ∫
0 9 · )−C 8 2 9 (C)' \ ()−C 8 −C)3C )−C 8 2 9 (C)' \ ()−C 8 −C)3C (23)
0 0
V 8, 9 ()) = ∫ ) = ∫ )
0 9 · 2 9 (C)' \ ()−C)3C 2 9 (C)' \ ()−C)3C
0 0