Why We’ll Need More Than Seven

“Stabilization Wedges”

Sustainability Institute10 Jan 08

CreditCreditLead ModelerDr. Tom Fiddaman, Ventana Systems

http://www.metasd.com/index.html

Modeling and FramingDr. John Sterman, MIT

http://web.mit.edu/jsterman/www/

Modeling, Framing, and Presentation DesignAndrew Jones, Sustainability Institutehttp://www.sustainabilityinstitute.org/

Lead ModelerDr. Tom Fiddaman, Ventana Systems

http://www.metasd.com/index.html

Modeling and FramingDr. John Sterman, MIT

http://web.mit.edu/jsterman/www/

Modeling, Framing, and Presentation DesignAndrew Jones, Sustainability Institutehttp://www.sustainabilityinstitute.org/

If Fossil Fuel Emissions Follow the “Business as Usual”

Path, CO2 in the Atmosphere Will Pass the Goal of 450 ppm

If Fossil Fuel Emissions Follow the “Business as Usual”

Path, CO2 in the Atmosphere Will Pass the Goal of 450 ppm

This is comparable to the IPCC “business as usual” future

What would it take to get CO2 in the atmosphere to stabilize under 450 ppm? How to get the blue line to fall to here?

Fossil Fuel Emissions24 B

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Goal

CO2 in the Atmosphere

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The Wedges Plan Proposes a “Flat path”, Leveling Emissions Through 2054 and

Then Reducing Them

The Wedges Plan Proposes a “Flat path”, Leveling Emissions Through 2054 and

Then Reducing Them So what would happen to CO2 in the atmosphere? Would we meet the goal?

Socolow and Pacala

How close to our goal would the “Flat path” bring us (With no

“post 2050” reductions)?

How close to our goal would the “Flat path” bring us (With no

“post 2050” reductions)?

Fossil Fuel Emissions24 B

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The “flat path”

Draw a line starting here

What if fossil fuel emissions flattened at 2007 levels? Sketch in the curve you think would result on the graph to the right.

Why?

Interactive Exercise

CO2 in the Atmosphere

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We Will Run Experiments in a Carbon Cycle Model Using

System Dynamics

We Will Run Experiments in a Carbon Cycle Model Using

System Dynamics

CO2 inAtmosphere

CO2 inMixed Layer

CO2 in DeepOcean

Flux Atm to Ocean

Diffusion Flux

CO2 inHumus

CO2 inBiomass

Flux Atm to Biomass

Flux Biomass to Atmosphere

Flux Biomass to Humus

Flux Humus to Atmosphere

<CO2Emissions>

Simplified Carbon Cycle Sector

We Simulated a Future Where We Just Level Emissions Along the

“Flat Path”

We Simulated a Future Where We Just Level Emissions Along the

“Flat Path”

When emissions follow the “flat path,” CO2 concentrations only grow more slowly. Why?

With no “post 2050” reductions

Fossil Fuel Emissions24 B

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The “flat path”

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Goal

CO2 in the Atmosphere

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“Flat path” results

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Think of CO2 in the Atmosphere as a Bathtub

Think of CO2 in the Atmosphere as a Bathtub

Emissions

CO2 in the atmosphere

Net Removals

The “flat path” caps emissions above removals. More is still flowing into the bathtub than is flowing out! So the level of water in the bathtub continues to rise.

The tub is filled by emissions and drained by net removals into oceans and biomass.

The inflow is roughly double the outflow

Emissions Still Exceed Removals

Emissions Still Exceed Removals

So CO2 in the atmosphere continues to increase.

Total Emissions and Removals

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The “flat path” for emissions

Net removals

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CO2 in the Atmosphere

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But The Wedges Plan Also Proposes

Reducing Emissions After 2054! But The Wedges Plan Also Proposes

Reducing Emissions After 2054!

Will that make the difference?

Socolow and Pacala

Reducing Emissions Post 2050 Puts Us On Track to Levelize

CO2 around 550 ppm

Reducing Emissions Post 2050 Puts Us On Track to Levelize

CO2 around 550 ppm

The “flat path” plus post 2054 reductions

Emissions exceed net removals all the way to 2100!

Fossil Fuel Emissions

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CO2 in the Atmosphere800

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The outcome of the “flat path” plus post 2050 reductions

Goal

What Happened? Why Didn’t Emissions

Level?

What Happened? Why Didn’t Emissions

Level?Total Emissions and Removals

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Despite reductions, Emissions exceeded Net Removals through 2100.

CO2 in the atmosphere will rise until the two meet.

CO2 in the Atmosphere

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Emissions

Net Removals

So What Will it Take To Stabilize CO2 in the Atmosphere Below Our

Goal?

So What Will it Take To Stabilize CO2 in the Atmosphere Below Our

Goal?

It Will Take an 80% Reduction in Fossil Fuel

Emissions

It Will Take an 80% Reduction in Fossil Fuel

Emissions

At this point, emissions equal net removals by 2050!

Fossil Fuel Emissions

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CO2 in the Atmosphere800

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Goal

80% Reduction Brings Emissions Down to Meet

Removals

80% Reduction Brings Emissions Down to Meet

RemovalsTotal Emissions and Removals

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Emissions

Net Removals

So levels of CO2 in the atmosphere stabilize.

Emissions CO2 in the atmosphere

Net Removals

So Meeting the Goal Will Require 7

Stabilizations, Plus 6-7 More So Meeting the Goal Will Require 7

Stabilizations, Plus 6-7 More

Socolow and Pacala

About 6-7 more wedges

Aggressive Sequestration (seq.) can boost

removals

Aggressive Sequestration (seq.) can boost

removals Sources of Total Removals6 B

4.475 B

2.95 B

1.425 B

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biomass

oceans

seq.

Results with 80% reduction in fossil fuel emissions plus 1.6 GTC/year in additional sequestration by 2050

CO2 in the Atmosphere800

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Goal

The Added Sequestration Boosts

Net Removals

The Added Sequestration Boosts

Net RemovalsTotal Emissions and Removals24 B

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Net Removals without additional sequestration

Net Removals with additional sequestration

So CO2 in the atmosphere balances out a little earlier and lower

More informationMore information Models on which the model that created these runs were based http://www.metasd.com/models/index.html#Climate

Interactive version covering some of these ideas http://www.seed.slb.com/en/scictr/watch/climate_change/challenge.htm

http://www.sustainabilityinstitute.org/tools_resources/climatebathtubsim.html

http://web.mit.edu/jsterman/www/GHG.html Video version

http://video.google.com/videoplay?docid=8235725143334110601&pr=goog-sl

Other related simulations http://www.sustainabilityinstitute.org/climate_change/simulations.html

Models on which the model that created these runs were based http://www.metasd.com/models/index.html#Climate

Interactive version covering some of these ideas http://www.seed.slb.com/en/scictr/watch/climate_change/challenge.htm

http://www.sustainabilityinstitute.org/tools_resources/climatebathtubsim.html

http://web.mit.edu/jsterman/www/GHG.html Video version

http://video.google.com/videoplay?docid=8235725143334110601&pr=goog-sl

Other related simulations http://www.sustainabilityinstitute.org/climate_change/simulations.html

More Notes on the Model

More Notes on the Model

“Emissions” in the model is total CO2 emissions. Including land use change emissions but not including the CO2 equivalents of other greenhouse gasses.

“Emissions” in the model is total CO2 emissions. Including land use change emissions but not including the CO2 equivalents of other greenhouse gasses.