The Ecological Footprint

2.83/2.813

T.G. Gutowski

Outline for 2/12/07

• Old business

– IPAT

– Birth rate and affluence

• New Business

– schedule change; readings, homework,

project posted

• Today

– The Ecological Footprint

Schedule change

• Next time: Scale Flow and CyclesScale Flow and CyclesScale Flow and CyclesScale Flow and Cycles, read Klee and Graedel, Smil 1 & 2

• One week from today; Sustainability?Sustainability?Sustainability?Sustainability?reading assignments, please sign up

February Monday Wednesday 7. Introduction

12. Eco-Footprint 14. Sustainability?

20. Scale, Flow and Cycles** 21. Exergy Accounting

26. Intro to LCA 28. Materials Production

March

5. Cutler Cleveland @ 12 noon 7. Mfg Processes

12. Mfg Processes 14. “Coal” discussion

19. Discussion 21. Quiz 1

26. (Spring Break) 28. (Spring Break)

April 2. LCA 4. Scale and Efficiency

9. Material Recycling 11. Product Recycling

16. (Patriots Day Holiday) 18. Product Reuse

23. Photovoltaics (TB) 25. Nanomfg (JI)

30. Presentations

May 2. Presentations

7. Project Follow-up 9. Field Trip

14. Review 16. Quiz 2

Reading Assignments for Next Monday

2/14 Sustainability?

a) Diamond, J., “Easter Island’s End” Discover Magazine, 1995. (6 pages)

http://www.hartford-hwp.com/archives/24/042.html

b) Broswimmer, “The Chaco Anasazi….,” p 45-48 (handout)

c) Hardin, G., “Tragedy of the Commons,” Science, 162, 1968, p 1243-1248.

http://dieoff.org/

d) Wilson, E.O., “The Bottleneck” pp 22 – 41, Ch 2 in The Future of Life, 2001 (handout)

e) Lomborg, B., “Biodiversity” in The Skeptical Environmentalist: Measuring the Real State of the World, 2001, p 251-257. (handout)

Current Homework in Red

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IPAT, additional examples

1. Automobiles and gasoline

2. pig iron and energy

3. global carbon

IPAT Equation Examples

Impact population service provided technology

“I” “P” car “T”

“A”

mile

gasoline

car

driven miles cars ofnumber gasoline ××=

1.What are the factors that influence the

amount of gasoline we burn in automobiles?

2. Energy used to make pig iron

iron pig

energy producediron pigEnergy

iron pig

energy

factory

iron pigfactories ofnumber Energy

×=

××=

Again the energy used per ton pig iron produced

depends upon the technology used.

3. Carbon emissions

1.5% 0.25% 1.25% 2% 1% Carbon

∆Carbon

GWP

Energy

Pop

GWPPopulationCarbon

+=−−++=

×××=Energy

Carbon

These are rough averages over the last 3 decades,

data taken or calculated from Pacala & Socolow, Science 2004

An underlying truth

From Smil

Please Do Your

Ecological Footprint

http://www.rprogress.org/

“Overhead”

Wackernagel’s paper and

worksheet

http://www.pnas.org/cgi/content/full/99/14/9266

http://www.pnas.org/content/vol0/issue2002/imag

es/data/142033699/DC1/0336DataSet.xls

Table 1. Summary of equivalence factors,

humanity's area demands, and earth's biological

capacity in 1999 (per capita)

Average global area demand (per

capita)

Existing global biocapacity

(per capita)

Area

Equivalence

factor, gha/ha Total demand,

ha (per capita)

Equivalent total,

gha (per capita)

World area,

ha (per

capita)

Equivalent total,

gha (per capita)

Growing crops 2.1 0.25 0.53 0.25 0.53

Grazing animals 0.5 0.21 0.10 0.58 0.27

Harvesting timber 1.3 0.22 0.29 0.65 0.87

Fishing 0.4 0.40 0.14 0.39 0.14

Accommodating infrastructure 2.2 0.05 0.10 0.05 0.10

Fossil fuel and nuclear energy 1.3 0.86 1.16 0.00 0.00

Total 2.33 1.91 1.91

To make aggregation reflect differences in bioproductivity, areas are expressed in standardized global hectares (gha), which

correspond to hectares with world average bioproductivity.

Wackernagel’s Results

Copyright ©2002 by the National Academy of Sciences

Wackernagel, Mathis et al. (2002) Proc. Natl. Acad. Sci. USA 99, 9266-9271

No Caption Found

Copyright ©2002 by the National Academy of Sciences

Wackernagel, Mathis et al. (2002) Proc. Natl. Acad. Sci. USA 99, 9266-9271

No Caption Found

Outline

• How much land is there?

• What do we do with this land?

• The production of biomass, NPP

• The sequestration of carbon, NEP

• Lifestyle and Product footprints

• National accounts

2R

R ≈ 6370 km

Surface area =

4πR2 = 510 X 106 km2

71% Oceans

29% Land = 148 Mkm2 = 14.8Gha

(one hectare = 100mX100m

one hectare = 2.47 acres)

There are 13.1 Gha not covered

by water or ice.

13.1/6.5 = 2 ha per person

on earth

(5 acres per person)

How much room is there?

Is there anybody else here

on earth besides us?

What do we do with this land?

deserts crops

wetlandsforests

grass land and cows

wilderness and built-up

Albers Projection (equal area)

showing croplands and cities

in Pimm, 2001

Net Primary Productivity

NPP = GPP – Ra

GPP = Gross Primary Productivity

(Photosynthesis)

Ra = autotrophic respiration

2612622 666 OOHCOHCO +→+

2612622 666 OOHCOHCO +←+

The Carbon Cycle

CO2 concentration in the atm

How do you measure NPP?

• buckets in the woods

• students with clippers

• satellites, see e.g.

http://asnerlab.stanford.edu/index.shtml

1kg/m2

dry mass

after Pimm

Area, biomass, productivity

from John Harte

estimate of NPP

from John Harte

Note, Pimm’s crude estimate would give

(1kg/m2 =0.45kgC/m2=4.5tC/ha) x 13.1Gha = 59 GtC

Earth Land Accounts (excluding Antartica)

Ref. Pimm 2004Note: Pimm uses (2.2:1) dry mass to carbon

this gives NPP = 52 Gt(C)

52115131Totals

.922004Other

1.94.220021“too dry”

--8“too cold”

1.22.613002Wet lands

5.712.550025Grass lands

11.625.5170015Corp lands

2044100044Other forests

10.924200012Rain forests

NPP

Gt C

NPP

Gt (dry mass)

Productivity

ton (dry mass)/km2

Area

106 km

2

Land Classiciation

(after Olson)

Carbon sequestration

NPP – Rh

Rh = heterotrophic respiration

– see websites at Oak Ridge National Labs

• http://csite.ornl.gov/

• http://cdiac.ornl.gov/home.html

Details of Canada’s Carbon

Carbon budget of Canada's forests

from 1895 to 1996. Also included is

the record of Canada's green-house

gas carbon emission rate.

Integrated Terrestrial Ecosystem

C-budget model

http://ccrs.nrcan.gc.ca/optic/coarse/beps/nep_e.php

World carbon emissions = C

Wackernagel’s Energy Area

Note:

there are some small differences in worksheet Vs paper

Anthropogenic carbon = 6.3 GtC (1999)

Nuclear (7% of world) add 0.5GtC

Carbon sequestration/yr Giga – “global” hectares

∴

GhaGhaha

tClandtoGtC 6.634.19.4

95.0

69.08.6 =×=×

Wackernagel’s result

Table 1. Summary of equivalence factors,

humanity's area demands, and earth's biological

capacity in 1999 (per capita)

Average global area demand (per

capita)

Existing global biocapacity

(per capita)

Area

Equivalence

factor, gha/ha Total demand,

ha (per capita)

Equivalent total,

gha (per capita)

World area,

ha (per

capita)

Equivalent total,

gha (per capita)

Growing crops 2.1 0.25 0.53 0.25 0.53

Grazing animals 0.5 0.21 0.10 0.58 0.27

Harvesting timber 1.3 0.22 0.29 0.65 0.87

Fishing 0.4 0.40 0.14 0.39 0.14

Accommodating infrastructure 2.2 0.05 0.10 0.05 0.10

Fossil fuel and nuclear energy 1.3 0.86 1.16 0.00 0.00

Total 2.33 1.91 1.91

To make aggregation reflect differences in bioproductivity, areas are expressed in standardized global hectares (gha), which

correspond to hectares with world average bioproductivity.

Wackernagel’s Results

Alternative Diets

• According to Pimm, the biomass from

cropland for human food is about ½ of

what is used for animals. Furthermore the

average diet calories come 5/6 from crops

and 1/5 from animal. Since animals also

use grazing land this makes meat about 3

times more land intensive in terms of

global hectares (even more so for actual

hectares).

Alternative Diets (using global hectares)

1 Gha (crops) for food + [2 Gha (crops) + 0.6 Gha

(grazing)] to feed animals = 3.6 Gt

average diet affluent diet

85% plants 65% plant

15% animals 35% animals

2250 kcal 3250 kcal

3.6Gha Vs 10Gha

1.2Gha (vegan) Vs 10Ghanote, does not include transportation, nor processing

ref. Pimm 2001, Smil 2006, Wackernagel 2002

Land to

Sequester C

We use 27%,

But are only

5% of

population

U.S. Energy

World Energy EJJGpeopleperson

GJ5.357105.3575.655 18

=×=×

EJGpeopleperson

GJ5.973.0325 =×

∴

%5 5.6

3.0 %;27

5.357

5.97⇒⇒

ha/person 6 0.3Gpeople

1.8Gha

hectares) (global 1.8Gha0.276.6Gha

=

=×

Footprint for An Automobile

Sequestion Area

Octane

C8H18

Assume

yrgalgalmile

yrmile/480

/25

/000,12=

368.0cm

g

gasoline

=ρ )(235.168.03785480

3785785.31

3

3

3

metrictcm

g

gal

cmgal

cmlitresgal

=××

==

gasoline

carbon842.0

114

96

18128

128==

+×

×

ture)infrastrucnor mfg. includenot does(

93.03.165.01.1/95.0

842.0235.1hahatc

hatc

t=××⇒

×

Energy used to heat home using

800 gallons of fuel oil/year

hectares global 1.23.16.1

95.0

65.3.2

3.2856.0

9.037858003

3

haha

ha

tC

tC

tCgOIL

gC

cm

g

gal

cmgal

=×⇒×

=×××

Who uses what

Natomo Family in Mali, March 27, 2003

MATERIAL WORLD, Peter Menzel

The Skeen Family, Pearland TX,

August 1993

MATERIAL WORLD, Peter Menzel

Criticism of the EF

• Bjorn Lomborg / The Economist

• Journal of Ecological Economics

• E. O. Wilson

Details of Canada’s Carbon

Carbon budget of Canada's forests

from 1895 to 1996. Also included is

the record of Canada's green-house

gas carbon emission rate.

Integrated Terrestrial Ecosystem

C-budget model

http://ccrs.nrcan.gc.ca/optic/coarse/beps/nep_e.php

February Monday Wednesday 7. Introduction

12. Eco-Footprint 14. Scale, Flow and Cycles

20. Sustainability?* 21. Intro to LCA

26. Exergy Accounting 28. Materials Production

March

5. Cutler Cleveland @ 12 noon 7. Mfg Processes

12. Mfg Processes 14. “Coal” discussion

19. Discussion 21. Quiz 1

26. (Spring Break) 28. (Spring Break)

April 2. LCA 4. Scale and Efficiency

9. Material Recycling 11. Product Recycling

16. (Patriots Day Holiday) 18. Product Reuse

23. Photovoltaics (TB) 25. Nanomfg (JI)

30. Presentations

May 2. Presentations

7. Project Follow-up 9. Field Trip

14. Review 16. Quiz 2

New ScheduleNew ScheduleNew ScheduleNew Schedule