Tools for global warming policy makers Harvey Lam, Princeton by muqbNr


									Tools for global warming policy makers
       Harvey Lam, Princeton University

    We accept the following premises

•      CO2 emitted by the burning of fossil fuels
is primarily responsible for the observed rise of
atmospheric CO2 content .
•     CO2 is a major greenhouse gas.
•     Continued and indefinite increase of CO2
can have significant adverse consequences.
•     The “fix” should have the consent of an
informed public.
         Critiques of
   current public discourse
1. Inadequate appreciation of the
   magnitude of the global warming
   problem. Confusion between global
   warming, energy independence, and
   air pollutions.
2. Inadequate appreciation of the time
   scale of the problem.
3. Inadequate appreciation of the role of
   the invisible hand of free market
   t      Time (years)
  C       Atmospheric carbon content (GtC)
  E       Annual emissions rate (GtC/yr)
  Cstab         Stabilized C target ceiling
  Estab         Allowed E when C=Cstab

CO2 concentration:       1 ppm=2.1 GtC
C(before 19th century)~286 ppm ~600 GtC
At the start of the 21 century
C(0)~800 GtC
E(0)~8 GtC/yr
dC/dt(0)~4 GtC/yr

Stabilization target
Cstab=1200 GtC (example)
Consequences of global warming
 • Global average temperature rise by
 between 2 and 4 degree Celsius for the
 “doubling” case.
 • More droughts and floods.
 • Sea levels rise.
 • ….

           When? How much more?
           How credible …?
     Common sense questions
A. How much total reduction of annual
   carbon emissions---fossil fuels usage---
   from our current value do we need?
B. Over how many years can we spread out
   the total reduction job if we start right
C. What penalty do we pay if we
   procrastinate? How do we monitor the
   state of the global warming world?
    A sample web link from
   “An Inconvenient Truth”
Want to do something to help stop global
  warming? Here are things you can do …
1. Use fluorescent lights
2. Drive less
3. Recycle more
4. Check your tires
5. Use less hot water
6. ….
     Messages from the media
• Windmills off Cape Cod? No.
• Nuclear energy? No.
• Perhaps the global GDP might drop 1%.
• Executive orders setting goals. Yes.
• Fine the polluters. Yes.
• Ethanol from corn. Yes.
• We can stop global warming now if we
only have the will.
            The punch lines
                  Cstab  600
     E stab (t)                 ( GtC / yr)
                      L (t)
      L (t)  200  (t  200) /2  200 (years)

                  2[Cstab  C(t)]
       CPM (t)                  (years)
                  dC(t) /dt
Best known stabilization curves
        (WRE, 1996)
            Meaning of Estab and L
                        Cstab  600
           E stab (t)                 ( GtC / yr)
                            L (t)
            L (t)  200  (t  200) /2  200 (years)

     Analogy to a college in steady state:
           Estab is (allowed) size of freshmen class.
          L is student residence time.
           Cstab-600 is current enrollment on campus.
Derivation of CPM(t)
                   2[Cstab  C(t)]
        CPM (t) 
                     dC(t) /dt

       CPM is short for
       Constant Pace Mitigation
           Mitigation job is
           done in CPM(t)

        Value of CPM(t) does not
        depend on science at all.
     Where does science come in?
     The following comes from published
     science-based studies:
                  Cstab  600
     E stab (t)                 ( GtC / yr)
                      L (t)
      L (t)  200  (t  200) /2  200 (years)
      Better science will provide better L(t;…).
      RepeatCPM(t) is independent of science.
       Answers to question A
For simplicity, we use L(t)~200 years
                       Cstab  600
            E stab   
     It is not a 10% or 20% problem!
           Cstab=1200, Estab=3 GtC/yr
         Cstab=1000, Estab=2 GtC/yr
           Cstab=900,        Estab=1.5 GtC/yr
           Cstab=800,        Estab=1 GtC/yr

     Currently, C~800 GtC, and E~8 GtC/yr
            Answers to question B
                    2[Cstab  C(t)]
         CPM (t) 
                      dC(t) /dt
     Its value depends on the chosen target ceiling
     Cstab, and the current (observed) values of
     C(t) and dC(t)/dt.
   Right now, C(0)=800 GtC, dC(0)/dt=4 GtC/yr.
           Cstab=1200, CPM(0)=200 years,
           Cstab=1000, CPM(0)=100 years.
Historical data of CPM(t)
           The CPM strategy
The CPM strategy is a benchmark strategy
which can serve as a guide line.
             dE     E  E stab
                
              dt 
                    CPM   CPM
The recommended pace of mitigation is
denoted by PCPM, defined by:
                    E  E stab
             PCPM   
                        CPM
 PCPM(t) and CPM(t) can be computed anytime.
              State of the
         global warming world
CPM(t) tells how many years do we have (at
most) to stabilized at the chosen Cstab.
PCPM(t) tells how much annual emissions
reduction is needed now to stabilized at the
chosen Cstab for each of the next CPM(t) years
(it is the lower bound of this value).
When we are not doing what we should be
doing, CPM(t) would drop by more than one
year each year, and PCPM(t) would rise.
     Answers to question C

Consequences of business-as-usual
The Do-the-best-we-can scenario
    Carbon cycle emulator
 Carbon that used to be buried
underground is being dug up, pumped
out, burned and emitted into the
 Once in the atmosphere, it somehow
migrates into the biosphere and the deep
ocean, leaving some to stay on.
 Conservation of carbon mass must be
     The Three-tank Model

Atmosphere   Biosphere   Deep Oceans
           The three-tank model
           dC     CB
           dt      S
             dB      CB BD
                      
              dt      S    L
             dD            BD
                       
             dt             L

     This is a linear model, with four constants:
     S, L,  and . E(t) is the forcing function.
In the fast S limit, it reduces to a
          two-tank model
            dC   1      C  D 
                   E        
            dt 1        L 
                dD           CD
                       
                dt           L
            B C

     Historical initial condition:
          C=B=D=600 GtC when E=0.
Comparison of the two-tank Model with

E(t) extracted from HILDA run vs original E(t)
   Historical data of 1/(1+)
taken when E was rising with time

             1     dC / dt
            1      E
1. A California bio-engineering team has
   cultivated a strain of termites that eats
   carbon based garbage, reproduces madly
   when exposed to sun light and water
   vapor, and dies happily as greasy oily
   balls which have the same chemical
   structure as crude oil from the Middle
   East. It can produce good quality crude oil
   at $20 per barrel.
2. OPEC announces a price cut and vows to
   defend its market share.
1. Global warming is not a 10% or 20%
   problem. It is a more than 60% problem.
2. No single technology is likely to be able to
   do the job. It needs the sum of all the 5%
   and 10% contributions it can get.
   Conservation helps. Fission nuclear
   should not be preemptively be discarded.
3. CPM(t) for several interesting Cstab’s
   should be publicized annually to keep the
   public informed.
4. Technology alone cannot solve the
   problem. The invisible hand of free market
   capitalism must be removed.
            Parting remarks
 Political leaders (Gore, Blair,
Schwarzenegger, Corzine, …) must
recognize that having the will to do the job is
not enough.
 The general public (you, me, and our
grandchildren, …) must be willing to pay the
costs and bear the burdens of doing the job.
 The global warming problem is much
bigger than the ‘energy independence’ and
the ‘air pollutions’ problems for which
conservation must play a dominant role.
          Socolow, R. H. and Lam, S. H.
Good enough tools for global warming policy making,
                      in   Energy for the Future,
           Philosophical Transactions of the Royal Society, 2007.

         Available at
Historical data of d(CPM)/dt
Plot of dC/dt vs E using solutions from the
             One-tank Model
Plot of dC/dt vs E for “parabolic immediately” cases
                 for several positive s

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