Comparing climate footprints withimpact-oriented life cycle methods: A meta-analysis
Mark A.J. Huijbregts
Department of Environmental Science, Radboud University Nijmegen, Nijmegen
In collaboration with Stefanie Hellweg, Rolf Frischknecht,
Konrad Hungerbühler, Harrie Hendriks and Jan Hendriks
Introduction
• Carbon footprinting is hot!
• Many methods available to perform
LCAs
• Which method should we use to
evaluate products?
• Does it make a difference?
!Introduction
!Aim
!Method
!Results
!Conclusions
Climate footprint
The climate footprint is a measure of the
total amount of carbon dioxide equivalent
emissions over the life cycle of a material,
product or service!Introduction
!Aim
!Method
!Results
!Conclusions
Meta-analysis
A meta-analysis is a statistical procedure to
combine a large number of existing studies.
Effects which are hard or impossible to discern
in the individual studies can be made visible!Introduction
!Aim
!Method
!Results
!Conclusions
Aims of the study
• Comparison of climate footprinting with
three single-score impact methodologies
by statistical analysis of the results for
498 materials
• Understand influence of fossil energy use
on the results
!Introduction
!Aim
!Method
!Results
!Conclusions
Method overview
!Introduction
!Aim
!Method
!Results
!Conclusions
Method Key characteristic
1. Climate Footprint (CF) Life-cycle greenhouse gas emissions
2. Ecological Scarcity (ES97) “Distance -to-political target” weighing
3. Environmental Priority Strategy (EPS2000) Monetarization of life -cycle i mpacts
4. Eco -Indicator 99 (EI99) Panel weighing of life -cycle impacts
1. Climate footprint
• Direct and indirect GHG emissions
• GWPs from IPCC (2007)
• Unit is CO2-equivalents
!Introduction
!Aim
!Method
!Results
!ConclusionsIPCC (2007). Global Warming Potentials
2. Ecological Scarcity• Distance to political target principle
• Emissions and resources
– Air emissions
– Water emissions
– Soil emissions, including waste
– Energy
• Unit is environmental impact points
!Introduction
!Aim
!Method
!Results
!Conclusions Brand, Scheidegger, Schwank, Braunschweig, 1998. Weighting in Ecobalances with the Ecoscarcity Method.Ecofactors 1997. Environmental Series No. 297. Swiss Federal Agency for the Environment, Bern.
3. Environmental Priority Strategy
• Damage towards protection targets
– Human health
– Ecosystem productivity
– Biodiversity
– Abiotic resources
• Monetary approach for weighting
• Environmental Load Units (= Euro)
!Introduction
!Aim
!Method
!Results
!Conclusions Steen, 1999. A systematic approach to environmental priority strategies in product development (EPS).Version 2000 – General system characteristics. CPM report 1999:4.
4. Ecoindicator 99
• Damage towards protection targets
– Human health
– Ecosystem health
– Resources
• Panel procedure for weighting
• Unit is Ecopoints
!Introduction
!Aim
!Method
!Results
!Conclusions Goedkoop & Spriensma, 2000. The Eco-Indicator 99, a Damage Oriented Method for Life Cycle Assessment.Pré Consultants: Amersfoort.
Data selection• Swiss ecoinvent database v1.3 + European Plastics Industry
!Introduction
!Aim
!Method
!Results
!Conclusions
Product group Number of materials
Agricultural products 65
Construction and insulation materials 42
Glass 11
Inorganic substances
121
Organic substances 146
Plastics 33
Metals 51
Paper and car dboard
29
Total 498
Standard and non-fossil datasetStandard selection:
• Includes all processes relevant for the material life
cycles considered
Non-fossil selection:
• Excludes transport, electricity and heat production
processes fuelled by fossil energy.
• Fossil feedstocks are excluded as well!Introduction
!Aim
!Method
!Results
!Conclusions
Statistical Analysis
• Univariate log-linear regression analysis
with Climate Footprint (CF) as
explaining variable
IS = Impact Score
bCFaIS +!= loglog!Introduction
!Aim
!Method
!Results
!Conclusions
Regression analysis – Ecoindicator
1,0E-05
1,0E-02
1,0E+01
1,0E+04
1,0E-03 1,0E+00 1,0E+03 1,0E+06
Climate Footprint (kg CO 2-Eq.kg-1
)
Eco
Ind
ica
tor
(eco
po
ints
.kg
-1)
Standard inventory
1,0E-05
1,0E-02
1,0E+01
1,0E+04
1,0E-05 1,0E-02 1,0E+01 1,0E+04
Climate Footprint (CO 2-Eq.kg-1
)
Eco
Ind
ica
tor
(eco
po
ints
.kg
-1)
Non-fossil inventory
logEI= 0.8 logCF – 0.9R2 = 0.74; SE = 0.38
logEI= 0.6 logCF – 1.0R2 = 0.35; SE = 0.75
Environmental Priority Strategy
Standard inventory Non-fossil inventory
logEPS= 1.1 logCF + 0.0R2 = 0.69; SE = 0.55
logEPS= 0.7 logCF + 0.3R2 = 0.29; SE = 0.97
1,0E-04
1,0E-01
1,0E+02
1,0E+05
1,0E+08
1,0E-03 1,0E+00 1,0E+03 1,0E+06
Climate Footprint (kg CO 2-Eq.kg-1
)
En
vir
on
me
nta
l P
rio
rity
Str
ate
gy (
EL
U.k
g-1
)
1,0E-05
1,0E-02
1,0E+01
1,0E+04
1,0E+07
1,0E-05 1,0E-02 1,0E+01 1,0E+04
Climate Footprint (CO 2-Eq.kg-1
)E
nvir
on
me
nta
l P
rio
rity
Syste
m (
EL
U.k
g-1
)
Ecoscarcity
Standard inventory Non-fossil inventory
logES= 0.9 logCF + 3.2R2 = 0.80; SE = 0.33
logES= 0.6 logCF + 3.5R2 = 0.49; SE = 0.59
1,0E+00
1,0E+03
1,0E+06
1,0E+09
1,0E-03 1,0E+00 1,0E+03 1,0E+06
Climate Footprint (kg CO 2-Eq.kg-1
)
EcoS
carc
ity (
UB
A.k
g-1
)
1,0E-01
1,0E+02
1,0E+05
1,0E+08
1,0E-05 1,0E-02 1,0E+01 1,0E+04
Climate Footprint (CO 2-Eq.kg-1
)E
coS
carc
ity (
UB
A.k
g-1
)
Non-fossil average contribution –Organic chemicals
!Introduction
!Aim
!Method
!Results
!Conclusions
Organic chemicals
0
20
40
60
80
100
CF ES EPS EI
Imp
ac
t (%
)
Non-fossil average contribution –Plastics
!Introduction
!Aim
!Method
!Results
!Conclusions
Plastics
0
20
40
60
80
100
CF ES EPS EI
Imp
ac
t (%
)
Non-fossil average contribution -Metals
!Introduction
!Aim
!Method
!Results
!Conclusions
Metals
0
20
40
60
80
100
CF ES EPS EI
Imp
ac
t (%
)
Non-fossil average contribution -Agriculture
!Introduction
!Aim
!Method
!Results
!Conclusions
Agricultural products
0
20
40
60
80
100
CF ES EPS EI
Imp
ac
t (%
)
Conclusions1. Climate Footprints point to the same
conclusions as more comprehensive impact
assessment methods
2. Fossil energy use has the most important
contribution to the environmental burden of
many materials included
3. For metal and agricultural products, non-
fossil energy related impacts dominate.
This aspect is not (fully) covered by climate
footprinting
!Introduction
!Aim
!Method
!Results
!Conclusions
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