Why We’ll Need More Than Seven “Stabilization Wedges” Sustainability Institute 10 Jan 08 Sustainability Institute 10 Jan 08

Credit  Lead Modeler  Dr. Tom Fiddaman, Ventana Systems   Modeling and Framing  Dr. John Sterman, MIT   Modeling, Framing, and Presentation Design  Andrew Jones, Sustainability Institute   Lead Modeler  Dr. Tom Fiddaman, Ventana Systems   Modeling and Framing  Dr. John Sterman, MIT   Modeling, Framing, and Presentation Design  Andrew Jones, Sustainability Institute 

If Fossil Fuel Emissions Follow the “Business as Usual” Path, CO 2 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 CO 2 in the atmosphere to stabilize under 450 ppm? How to get the blue line to fall to here? Fossil Fuel Emissions 24 B 18 B 12 B 6 B TonC/year Goal CO2 in the Atmosphere ppm

The Wedges Plan Proposes a “Flat path”, Leveling Emissions Through 2054 and Then Reducing Them So what would happen to CO 2 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)? Fossil Fuel Emissions 24 B 18 B 12 B 6 B TonC/year 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 ppm

We Will Run Experiments in a Carbon Cycle Model Using System Dynamics

We Simulated a Future Where We Just Level Emissions Along the “Flat Path” When emissions follow the “flat path,” CO 2 concentrations only grow more slowly. Why? With no “post 2050” reductions Fossil Fuel Emissions 24 B 18 B 12 B 6 B 0 The “flat path” TonC/year Goal CO2 in the Atmosphere “Flat path” results ppm

Think of CO 2 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 So CO 2 in the atmosphere continues to increase. Total Emissions and Removals 24 B 18 B 12 B 6 B 0 The “flat path” for emissions Net removals TonC/year CO2 in the Atmosphere ppm

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 CO 2 around 550 ppm The “flat path” plus post 2054 reductions Emissions exceed net removals all the way to 2100! Fossil Fuel Emissions 24 B 18 B 12 B 6 B TonC/year CO2 in the Atmosphere ppm The outcome of the “flat path” plus post 2050 reductions Goal

What Happened? Why Didn’t Emissions Level? Total Emissions and Removals 24 B 18 B 12 B 6 B TonC/year Despite reductions, Emissions exceeded Net Removals through CO2 in the atmosphere will rise until the two meet. CO2 in the Atmosphere Goal Emissions Net Removals

So What Will it Take To Stabilize CO 2 in the Atmosphere Below Our Goal?

It Will Take an 80% Reduction in Fossil Fuel Emissions At this point, emissions equal net removals by 2050! Fossil Fuel Emissions 24 B 18 B 12 B 6 B TonC/year CO2 in the Atmosphere ppm Goal

80% Reduction Brings Emissions Down to Meet Removals Total Emissions and Removals 24 B 18 B 12 B 6 B TonC/year 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 Socolow and Pacala About 6-7 more wedges

Aggressive Sequestration (seq.) can boost removals Sources of Total Removals 6 B B 2.95 B B -100 M Time (year) TonC/year biomass oceans seq. Results with 80% reduction in fossil fuel emissions plus 1.6 GTC/year in additional sequestration by 2050 CO2 in the Atmosphere ppm Goal

The Added Sequestration Boosts Net Removals Total Emissions and Removals 24 B 18 B 12 B 6 B TonC/year Net Removals without additional sequestration Net Removals with additional sequestration So CO2 in the atmosphere balances out a little earlier and lower

More information  Models on which the model that created these runs were based   Interactive version covering some of these ideas  nge.htm nge.htm  htubsim.html htubsim.html   Video version  1&pr=goog-sl 1&pr=goog-sl  Other related simulations  s.html s.html  Models on which the model that created these runs were based   Interactive version covering some of these ideas  nge.htm nge.htm  htubsim.html htubsim.html   Video version  1&pr=goog-sl 1&pr=goog-sl  Other related simulations  s.html s.html

More Notes on the Model  “Emissions” in the model is total CO 2 emissions. Including land use change emissions but not including the CO 2 equivalents of other greenhouse gasses.