Carbon Emissions: Past, Present, & Future

Carbon Emissions:

Past, Present, & Future

Chris Field

Carnegie Institution: Department of Global Ecology

[email protected], www.global-ecology.org

Role of the IPCC• Comprehensive assessment• Multiple layers of monitored review• Consensus approval by governments

More than 30% increase in atmospheric CO2 since thebeginning of the industrial revolution

Recently---

• 2006 CO2 – 381 ppm• Fossil emissions in 2006 = 8.4 Pg C

– 35% above 1990– Rate of increase 2000-2006 = 3.3%– Rate of increase 1990-1999 = 1.3%

• Atm growth rate 2000-2006 = 1.93 ppm/yr– 30% above 1990-2000

Field et al. 2007 SOCCR

IPCC 2007

Raupach et al 2007, PNAS

EIA

Carb

on e

mis

sion

s (m

illio

ns o

f to

ns/y

r)

Raupach et al. 2007 PNAS

IPCC 2007

Finding the mechanism

Carbon

inten

sity

Of eco

nomic

activ

ityPer

capit

a GDP

Popula

tion s

ize

Raupach et al 2007, PNAS

0.50.60.70.80.9

1

1.1

1.21.31.41.5

19800.50.60.70.80.9

1

1.1

1.21.31.41.5

1980

World

0.5

0.6

0.70.8

0.9

1

1.1

1.21.3

1.4

1.5

1980 1985 1990 1995 2000 2005

F (emissions)P (population)g = G/Ph = F/G

Facto

r (re

lative

to 19

90)

EmissionsPopulationWealth = per capita GDPCarbon intensity of GDP

Anthropogenic C Emissions: Carbon Intensity of GDP

Emissions increasing everywhere

Emissions

Population

Wealth

Carbonintensity

Dramatic contrast – history versus future

0%

20%

40%

60%

80%

100%C

O2

emis

sion

sDeveloping

IndiaChina

Former SovietOther developed

Japan

Europe

USA

CumulativeRaupach et al. 2007 PNAS

Cumul Flux0%

20%

40%

60%

80%

100%C

O2

emis

sion

sDeveloping

India

China


Japan

Europe

USA

Cumul Flux Growth0%

20%

40%

60%

80%

100%C

O2

emis

sion

sDeveloping

India

China


JapanEurope

USA

Cumul Flux Growth Pop0%

20%

40%

60%

80%

100%C

O2

emis

sion

sLeast Developed

Developing

India

ChinaFormer Soviet

Other developedJapanEurope

USA

FAO-Global Resources Assessment 2005; Canadell et al. 2007, PNAS

Tropical Americas 0.6 Pg C y-1

Tropical Asia 0.6 Pg C y-1

Tropical Africa 0.3 Pg C y-1

2000-2005

Tropical deforestation13 Million hectares each year

Anthropogenic C Emissions: Land Use Change

1.5 Pg C y-1

Born

eo, C

ourte

sy: V

iktor

Boe

hm

deforestationtropics

extra-tropics 1.5

2000-2006

Le Quéré, unpublished; Canadell et al. 2007, PNAS

CO2

flux (

Pg C

y-1)

Sink

Sour

ce

Time (y)

Perturbation of Global Carbon Budget (1850-2006)

deforestation

fossil fuel emissions

7.6

1.5

2000-2006

CO2

flux (

Pg C

y-1)

Sink

Sour

ce

Time (y)


Le Quéré, unpublished; Canadell et al. 2007, PNAS


deforestation

7.6

1.5

2000-2006

CO2

flux (

Pg C

y-1)

Sink

Sour

ce

Time (y)


Canadell et al. 2007, PNAS


deforestation

7.6

1.5

4.1

2000-2006

CO2

flux (

Pg C

y-1)

Sink

Sour

ce

Time (y)

atmospheric CO2



atmospheric CO2

ocean

land


deforestation

7.6

1.5

4.1

2.22.8

2000-2006

CO2

flux (

Pg C

y-1)

Sink

Sour

ce

Time (y)



1960 1970 1980 1990 2000

time

Dis

tribu

tion

(frac

tion)


An increasing airborne fraction

• Airborne Fraction– 10% Increase (p = 0.11)– 0.25% y-1

And a decreasing ocean fraction

• Land fraction– 0.6% y-1

• Ocean fraction– -0.42% y-1

Dis

tribu

tion

(frac

tion)

• up to 30% decrease in the efficiency of the Southern Ocean sink over the last 20 years

• strengthening of the winds around Antarctica increases exposure of carbon-rich deep waters

• strengthening of the winds from global warming and the ozone hole

Declining efficiency of the ocean sink

Le Quéré et al. 2007, Science

Canadell et al 2007, PNAS

0.50.60.70.80.9

1

1.1

1.21.31.41.5

19800.50.60.70.80.9

1

1.1

1.21.31.41.5

1980

World

0.5

0.6

0.70.8

0.9

1

1.1

1.21.3

1.4

1.5

1980 1985 1990 1995 2000 2005


Facto

r (re

lative

to 19

90)

Emissions

Attributing the change in the atmospheric growth rate


• The eroding trend in C intensity

• The increasing airborne fraction

• Increased economic activity


0.50.60.70.80.9

1

1.1

1.21.31.41.5

19800.50.60.70.80.9

1

1.1

1.21.31.41.5

1980

World

0.5

0.6

0.70.8

0.9

1

1.1

1.21.3

1.4

1.5

1980 1985 1990 1995 2000 2005


Facto

r (re

lative

to 19

90)

Emissions

Carbon intensity of GDP

C intensity

= 17±6%

Airborne fraction

• ∆ = trend * time interval * emissions• = 18±15%

Dis

tribu

tion

(frac

tion)



• The eroding trend in C intensity = 17±6%

• The increasing airborne fraction = 18±15%

• Increased economic activity = 65±16%

Size of the challenge

• World economy in 2050 ~4x current• C emissions in 2050 no more than current• 4-fold improvement in C intensity

• World economy in 2100 ~10-20x current• C emissions in 2100 ~0.5x current• 20- 40-fold improvement in C intensity

Size of the challenge (2)

• Global energy use ~ 15 TW (15 x 1018 W)• Global economic growth ~3% yr-1

• 3% of 15 TW = 450 GW– 450 new big powerplants

• Past intensity improvements ~1.5% yr-1

– 225 new big powerplants

The fate of future emissions• CO2 has a long atmospheric lifetime

– ~50% removed in a century– As much as 25% persists over 5000 years

100 200 300 400 500Model year

ppm

CO

2

Matthews & Caldeira GRL 2008

But ocean heat uptake falls in parallel with atmospheric CO2

100 200 300 400 500Model year

ppm

CO

2S

urfa

ce Δ

T (º

C)


Stabilizing climate = 0 emissions

2000 2100 2200 2300 2400 2500Model year

Sur

face

ΔT

(ºC

)


Stabilizing climate = 0 emissions

2000 2100 2200 2300 2400 2500Model year

Sur

face

ΔT

(ºC

)

Cum

ulat

ive

emis

sion

s (P

g C

)


• Fossil emissions growing rapidly

• Carbon intensity stalled or degrading

• Ocean sink weakening

• Growth rate of atmospheric CO2increasing

• Stabilizing climate requires reducing CO2 emissions to zero

Carbon Emissions: Past, Present, & Future

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