The Global Carbon Cycle

Integrating Humans, Climate and the Natural World

Island Press – 2004

SCOPE

SCOPE 62

COP9, Milan, Dec.8th, 2003,Side EventOutline

• Christopher Field, Carnegie Institution, Stanford, California, cfield@globalecology.stanford.edu

• Dorothee Bakker, University of East Anglia, Norwich, UK, d.bakker@uea.ac.uk

• Patricia Romero Lankao, Universidad Autonoma Metripolitana, Mexico City, Mexico, rolp7543@cueyatl.uam.mx

• Josep Canadell, CSIRO Land and Water, Canberra Australia, pep.canadell@csiro.au

Revised c budget

Land C budget (1980-2000)

Net land sink 0.6 Pg y-1

Deforestation 1.2 Pg C y-1

Residual land sink 1.8 Pg C y-1

New Understanding

• Inertia

• Saturation

• Vulnerability

• The Energy Gap

• A Common Framework

Inertia

• Many current sinks a result of past actions

• Entrained warming continues for many decades

• Key technologies require fundamental development

Inertia 2• Inertia chart

Vulnerability

• On Land: Several large pools poised for large releases in a warming climate

– C in permafrost soils

– Wildfire

– Tropical forests

WarmingCarbon

release

Tropical forests

Warming

Increased

respiration

Decreased

growth

Increased

fire Low to moderate

Ocean compensation

700 Pg C gain

Becomes

100 Pg C loss

Extra 350 ppm CO2 in Atm

Cox et al. 2000. Nature 408: 184

Vulnerability 2

The Energy Gap

• Scenarios contain optimistic efficiency increases– still fail to stabilize below 750– do not yet account for all sources of

vulnerability

Technology improvement for IS 92a

The oceanic carbon cycle in a changing climate

Blue planet: Oceans and seas cover 71 % of the globe (Tchernia, 1980).

The oceans store 88% of global carbon outside geological reservoirs (IPCC, 2001). (BBC; 6 years of SeaWiFS data, DAAC/GSFC,

ORBIMAGE)

2.0

10.0

0.1

0.01

0.5

50.0

Chlorophyll a (mg/m3)

Oceanic uptake of fossil fuel CO2

(Keeling and Bates)

- BATS (Bermuda)

Tota

l C

O2

(µm

ol/

kg

)

1988 1990 1992 1994 1996 1998

CO

2 c

on

ten

t (µ

mol/

mol)

- Hawaii370

350

310

330

2060

2030

2000

20001970

Oceanic sink for anthropogenic CO2

Based on 40 years of surface pCO2 data (Takahashi et al., 2002)

The oceans absorb 27% of the anthropogenic CO2

emissions or 1.7 +/- 0.5 Pg C/yr (IPCC, 2001).

Quantification of oceanic CO2 sources/sinks puts a constraint on land sources/sinks.

1 CO2 Air-Sea exchange

Sea floor

CO2 (aq) + H2O H2CO3

HCO3-

H+ + HCO3-

H+ + CO32-

H2CO3

Total CO2 1020

~100 m

Lysocline~3500 m

CO2

730

Atmosphere

(in Pg C; after IPCC, 2001, Fig. 3.1)

Surface Ocean

DeepOcean

Sh

elf

CO2 air-sea flux = - K •(pCO2air - pCO2water)Driving force for oceanic uptake of anthropogenic CO2

Sea floor

CO2 (aq) + H2O H2CO3

HCO3-

H+ + HCO3-

H+ + CO32-

H2CO3

Total CO2 38,000

Total CO2 1020

~100 m

Lysocline~3500 m

CO2

730

Atmosphere

(in Pg C; after IPCC, 2001, Fig. 3.1)

Surface Ocean

DeepOcean

Sh

elf

Determines the rate of oceanic uptake of anthropogenic CO2

2 Physical pump

Sea floor

Organic matter

CO2 (aq) + H2O H2CO3

HCO3-

H+ + HCO3-

H+ + CO32-

H2CO3

Total CO2 38,000

CaCO3

Total CO2 1020

~100 m

Lysocline~3500 m

CO2

730

Atmosphere

(in Pg C; after IPCC, 2001, Fig. 3.1)

Surface Ocean

Biota 3

DeepOcean

Sh

elf

<700

3 Physical and Biological pump

Sea floor

Total carbon

Total carbon

~100 m

Surface Ocean

Organic carbon

DeepOcean

Sh

elf

(in Pg C; after Gruber et al., SCOPE)

CO2 system

Warming BiologyCirculationAnthro-pogenic

BufferCapacity Natural

cycle<20% ?

<3% ?[<20%] 50% ?[30%]

CaCO3

Climate changeAnthropogenic CO2 uptake

50% ?

Relative to 600-700 Pg C of cumulative oceanic uptake of anthropogenic CO2 for 2000 - 2100.

4 Feedbacks on oceanic CO2 uptake

A reduction of calcification by oceanic uptake

of anthropogenic CO2

(Greenblatt and Sarmiento, SCOPE book; Jeremy Young, Natural History Museum, London; Steven Cook, Florida Keys National Marine Sanctuary)

Calcifying algaeEmiliania huxleyi;A bloom in the English Channel.

Brain coral and sea fan,Florida Keys

North Atlantic Carbon Observing System

90°W 50°W 10°W

Greenland-Denmark

New York–Halifax-

Hamburg

Caribbean –

Portsmouth

Sou

th-A

meri

ca-S

pain

Cruise tracks CAVASSOO 2001 – 2003 EU project

Greening the oceans

Courtesy Sue Turner (UEA)

by iron fertilisationto combat global warming?

High nutrients

[after Conkright et al., 1998]

µM0 5 10 15 20 25Nitrate

Low chlorophyll

2.0

10.0

0.1

0.01

0.5

50.0

Chlorophyll a (mg/m3)

(6 years of NASA SeaWiFS data, DAAC/GSFC, ORBIMAGE)

Only the Southern Ocean has a potential for long term CO2 storage by iron fertilisation (circulation).

DMS and climate

AlgaeDMS

Degradation/Loss

DMS

SO2

Sulphate AerosolH2SO4 Radiation

Budget

DMS = dimethyl sulphide

Greening the oceans to combat global warming?

Poorly known efficiency of CO2 storage.

Warming by the production of the greenhouse gases N2O and CH4 could outweigh cooling by CO2 storage (Jin and

Gruber, 2002).

Climate feedbacks by the production of DMS, halocarbons and alkyl nitrates.

Unknown, major shifts in the marine ecosystem.

The oceans absorb 27% of anthropogenic CO2 emissions.

Strong feedbacks in the marine carbon cycle will reduce oceanic CO2 uptake relative to the increase in atmospheric CO2 for 2000-2100.

Net oceanic CO2 uptake will reduce calcification and coral reef formation.

The oceanic carbon cycle in a changing climate

Drivers of GHG, Kaya identity*

CO2 =(CO2 /E) x (E/GWP) x (GWP/P) x

where• P = Population growth• GWP/P = Per capita gross world product• E/GWP = Energy requirement per unit

of gross product

• CO2 /E = CO2 emissions per unit of energy

Historical and future trends of drivers

• CO2 emissions grew 1.7% (1900), double next 3 decades

• Population grew 1.3% (1900), double ≥70 years

• GWP grew 4% (1950), 3.5 to ≥32 times in 2100• Weak relation population / economic growth• Primary energy consumption 2% (1900), will

growth 1.3% • E. growth => capital turnover => less energy

intensity; decarbonization

Key common trends

1. Exponential increase in LUC 2. Shift from biomass to fossil fuels3. From LUC to fossil fuels as main

proximate cause4. Urbanization became major global

driver of GHG (urban sprawl)5. Key driver globalized trade

dominated by few countries

Diverse regional pathways of development (1)

Developed countries• Highest share of trade, production,

energy use and emissions• Slow urban growth • High ecological footprint (8-15 times)• Decreased LUC • Higher ability to deal with

mitigation/adaptation?

Diverse regional pathways of development (2)

Two clusters:1. During 1970-90 increased share of trade,

production, energy and emissions, high urban growth, aggressive states

2. Industrialization, still dependant primary commodities, high urban growth, weak states, recurrent crisis

Could first cluster have increased capacity for mitigation/adaptation strategies?

Diverse regional pathways of development (3)

High primary commodity-export economies in Africa, Latin America and Asia with:

• Insignificant participation in production, trade, energy and emissions

• Vulnerable to vagaries of international markets and to climate vulnerability and change

• Economic crisis and stagnation, segregation hamper promotion of carbon relevant policies

Hydrogen Fuel Cell Vehicles

Zero Net Emission Buildings

Nuclear Power Generation IV

Renewable Energy Technologies

Vision 21: Zero-Emission Power Plant

Bio-Fuels and Power

Carbon (CO2) Sequestration

• Deep cuts in emissions require

advanced technologiesSOON

• No single technologycan do it all

• Some constraints

Portfolio ofTechnological Solutions

Plant New Forests

Ocean Fertilization

Reduced deforestation

Sequestration in Ag. soils

Reduced methane production

• Can be implementedimmediately

• Not long term solutions

•Potential for ancillary

costs and benefits

Portfolio ofBiological Solutions

Multiple constraints on C mitigation options

• Economics.• Social factors.• Institutional factors.• Institutional and timing aspects of technology

transfer.• Demography.• Environmental requirements for other resources.

SustainablyAchievablePotential

Carbon Sequestered or GHG emissions avoided (tCeq)

BaseLine

Cos

t of

car

bon

($/t

Ceq

)

Social and Institutions

EconomicalFactors

Economic Structure

Urbanization

Industrialization

Social:Class structureLife style

AttitudeBehavior

PoliticsFormal policiesInformal rules

Property rights

Demographic:

Density, growthMigration

Spatial distribution

Institutional:

Economic Structure

Mitigation Potential

TechnicalPotential

EnvironmentalFactors

Land, water,Biodiversity,Navigation andFisheries rights

Timing

Generation transfer

Markets

Trade

Effects of economic, environmental and social-institutional factors on the mitigation potential of a carbon management strategy

Potential mitigation with sustainability principles

Land-BasedC Sequestration

Projects

ClimateMitigation

Land-based C mitigation options

BiodiversityConservation

ErosionPrevention

BiomassEnergy

WaterYield

Soil Fertility

Use of Wood

Products

Sustainable

Regional DevelopmentRecreationalValue

Win-winC sequestr.BiodiveresityCombat salinization

C sequestration in Ag.Soil fertility

Multiple-constraints

Theoretical vs. Achievable PotentialGlobally, enhanced terrestrial sequestration and energy cropping for the next 50 years could offset (Gt C yr-1) (Cannell 2003)

15-EU, sequestration in agricultural soils for the first Kyoto commitmentperiod (2008-2012) could offset (Mt C yr-1) (Freibauer et al. 2003)

Achievablepotential

16-19

100% 15%

Theoreticalpotential

~90

Theoretical Potential

2-5

Realistic Potential

1-2

Conservatively Achievable

0.2-1

100% 10-20%

Conclusions• Vulnerability of carbon pools

– The higher the CO2 concentrations the higher the risk of destabilizing vulnerable carbon pools (eg, permafrost, tropical peatlands).

• Inertia of the carbon cycle and energy systems– Even when anthropogenic CO2 emissions begin to decrease,

atmospheric CO2 will continue to go up for up to a century.– Inertia of technology transfer

• Sustainability criteria in sequestration and emission reduct.– Particularly on biological sequestration, realistically achievable potential

is much less than theoretical potential.

• Saturation of sink mechanisms– If NH sinks is largely due to forest regrowth, the sink strength will

disappear within decades. Saturation of the CO2 fertilization effect on plan productivity occurs at around 600 ppm.

Conclusions (ii)

• Likely acceleration of climate change as the century progresses beyond what climate models are currently predicting.

• Early action on carbon mitigation while terrestrial sinks are strong, and positive feedbacks are less likely.

ObservationsIntegrated Global

Observing Strategy

ResearchGlobal Carbon

Project&

Partners

International efforts on carbon cycle research

AssessmentIPCC

International Geosphere-Biosphere Program

IHDP WCRP

Global Carbon Project

World ClimateResearch ProgramInternational Human

Dimensions Program

IGBP

National and regional carbon research programmes

LBA

CarboEurope

China

Australia

North AmericaCarbon Plan

Siberia

Jp

SA

NZ

Canada

GCP Objective

To develop comprehensive, policy-

relevant understanding of the global carbon cycle, encompassing its natural and human dimensions and their interactions.

www.globalcarboproject.orgpep.canadell@csiro.au

Research activities

• Urbanization pathways to minimize C emissions.• Attribution of terrestrial sinks to mechanisms.• Full carbon accounting methodologies.• Vulnerability of carbon pools on land and in oceans.• Model-data fusion approaches.• Coordination of ocean cruise programmes.• State-of-the-art synthesis of the carbon cycle.• Capacity building: institutes and summer courses.• Fostering integrated carbon research in LDC.

GCP International Project and Affiliate Offices

CSIRO,Canberra Australia

NIES,TsukubaJapan (April 2004)

USA

CarboEurope, GermanyGHG CA, Italy

IOC/SCOR-CO2 PanelParis, France

Beijing, China

Affiliate Off.Proposed only

Affiliate Off.

Inter.Proj.Off.