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