Double-Bind in Seeking Global Prosperity Alongside Mitigated Climate Change
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Earth Syst. Dynam., 3, 1–17, 2012 www.earth-syst-dynam.net/3/1/2012/ Earth System doi:10.5194/esd-3-1-2012 Dynamics © Author(s) 2012. CC Attribution 3.0 License. No way out? The double-bind in seeking global prosperity alongside mitigated climate change T. J. Garrett Department of Atmospheric Sciences, University of Utah, Salt Lake City, Utah, USA Correspondence to: T. J. Garrett ([email protected]) Received: 21 March 2011 – Published in Earth Syst. Dynam. Discuss.: 6 April 2011 Revised: 3 December 2011 – Accepted: 31 December 2011 – Published: 5 January 2012 Abstract. In a prior study (Garrett, 2011), I introduced a may be in a double-bind. If civilization does not collapse simple economic growth model designed to be consistent quickly this century, then CO2 levels will likely end up ex- with general thermodynamic laws. Unlike traditional eco- ceeding 1000 ppmv; but, if CO2 levels rise by this much, nomic models, civilization is viewed only as a well-mixed then the risk is that civilization will gradually tend towards global whole with no distinction made between individual collapse. nations, economic sectors, labor, or capital investments. At the model core is a hypothesis that the global economy’s cur- rent rate of primary energy consumption is tied through a 1 Introduction constant to a very general representation of its historically ac- cumulated wealth. Observations support this hypothesis, and Despite decades of public awareness of the potential for fos- indicate that the constant’s value is λ = 9.7 ± 0.3 milliwatts sil fuel consumption to lead to dangerous climate change, per 1990 US dollar. It is this link that allows for treatment anthropogenic emissions of CO2 have accelerated (Canadell of seemingly complex economic systems as simple physi- et al., 2007; Raupach et al., 2007). The implications of civ- cal systems. Here, this growth model is coupled to a linear ilization continuing on this path are environmental changes formulation for the evolution of globally well-mixed atmo- that are both irreversible and profound, including amplified spheric CO2 concentrations. While very simple, the coupled hydrological extremes, storm intensification, sea level rise, model provides faithful multi-decadal hindcasts of trajecto- and extreme mammalian heat stress (Hansen et al., 2007; ries in gross world product (GWP) and CO2. Extending the Allan and Soden, 2008; Solomon et al., 2009; Vermeer and model to the future, the model suggests that the well-known Rahmstorf, 2009; Sherwood and Huber, 2010). IPCC SRES scenarios substantially underestimate how much The economic costs associated with addressing and cop- CO2 levels will rise for a given level of future economic pros- ing with climate warming are normally quantified by cou- perity. For one, global CO2 emission rates cannot be decou- pling a system of economic equations to a medium complex- pled from wealth through efficiency gains. For another, like ity climate model. Normally, these Integrated Assessment a long-term natural disaster, future greenhouse warming can Models (IAMs) make regionally-based assessments of the be expected to act as an inflationary drag on the real growth economics of production, investment, consumption, welfare, of global wealth. For atmospheric CO2 concentrations to re- discount rates, population and rates of technological change. main below a “dangerous” level of 450 ppmv (Hansen et al., These economic functions are coupled to functions for at- 2007), model forecasts suggest that there will have to be mospheric temperature and climate damage. From within some combination of an unrealistically rapid rate of energy a parameter space that might be of order 100 variables, the decarbonization and nearly immediate reductions in global model outcome is a long-term optimized trajectory for long- civilization wealth. Effectively, it appears that civilization term societal welfare to which policy measures (for example Published by Copernicus Publications on behalf of the European Geosciences Union. w ="µdň/dt a = !ň"µ = !"G "µ Accessible ~a energy reservoirs ň Interface System Newly accessible energy reservoirs Surroundings 2 T. J. Garrett: Coupled evolutionThermodynamic of the economy and the atmosphere w ="µdň/dt P = dC/dt a = G !ň"µ = !" "µ a = #C Accessible ~a Accessible energy reservoirs ň ~a System energy reservoirs Interface Civilization Interface Newly accessible Newly accessible energy reservoirs energy reservoirs Surroundings Surroundings Thermodynamic Economic Fig. 1. Schematic for the thermodynamic evolution of an openFig. system, 1. Schematic and its for hypothesizedthe thermodynamic economic evolution of representation. an open system, and Energy its hypothesized reservoirs, economic rep- ˘ civilization, and its surroundings lie along distinct constant potentialresentation. surfaces. Energy The reservoirs, number civilization, of material and its surroundings units n defining lie along an distinct interface constant between potential surfaces. civilization and energy reservoirs determinesP the= dC/dt speed of downhill energetic flow at rate a, in proportion to a fixed specific potential The number of material units n˘ defining an interface between civilization and energy reservoirs determines the difference 1µ and rate coefficienta = #C α. The interface itself grows or shrinks at rate w due to a net flux convergence into civilization. In speed of downhill energetic flow at rate a, in proportion to a fixed specific potential difference ∆µ and rate a positive feedback,Accessible interface growth at rate dn˘/dt~aexpands energetic flows a by extending civilization’s access to previously inaccessible energy reservoirs coefficient α. The interface itself grows or shrinks at rate w due to a net flux convergence into civilization. In a energy reservoirs at rate da/dt. Fiscally,Civilization wealth C is proportional to both the interface size n˘ and the rate of primary energy consumption a. Interface positive feedback, interface growth at rate dn/dt˘ expands energetic flows a by extending civilization’s access to The GWP P represents the net expansion of wealth at rate dC/dt due to interface growth. C and a are linked through a constant λ. See the Newly accessible previously inaccessible energy reservoirs at rate da/dt. Fiscally, wealth C is proportional to both the interface energy reservoirs text and Garrett (2011) for details. Surroundings size n˘ and the rate of primary energy consumption a. The GWP P represents the net expansion of wealth at rate dC/dt due to interface growth. C and a are linked through a constant λ. See the text and Garrett (2011) Economic for details. the Copenhagen Accord) can be compared (Nordhaus and part of the physical universe and it is modeled as any other Fig. 1. SchematicBoyer, for2000 the thermodynamic; Keller et evolution al., 2004 of an; Nordhaus open system,, and2010 its hypothesized). Uncer- economicphysical rep- system. Long-term growth in global consumption resentation.tainty Energy in reservoirs, the optimal civilization, path, and when its surroundings addressed, lie along is distinct modeled constant using potential surfaces.and emission rates are considered only as a thermodynamic The numberMonte of material Carlo units simulationsn˘ defining an interface within between a portion civilization of and the energy total reservoirs param- determinesresponse the to civilization’s expansion into newly available en- speed of downhilleter space energetic (Mastrandrea flow at rate a, in and proportion Schneider to a fixed, 2004 specific). potential difference ∆µ andergy rate resources. coefficient α.Modern The interface IAMs itself grows are ornormally shrinks at rate w baseddue to a on net flux mainstream convergence into neo- civilization. InThus, a unlike IAMs, this article does not evaluate what positive feedback, interface growth at rate dn/dt˘ expands energetic flows a by extending civilization’s access to 29 classical economic growth models that, unlike climate mod- long-term policy actions will enable us to limit CO2 emis- previouslyels, inaccessible do not energy explicitly reservoirs represent at rate da/dt. flows Fiscally, as wealth a materialC is proportional flux down to both the interfacesions while maximizing global economic wealth. Rather, the size n˘ andpressure the rate of primary gradients. energy consumption Economica.flows The GWP areP represents allowed the to net become expansion of wealthaim at is to explore the range of future trajectories that is ac- rate dC/dt due to interface growth. C and a are linked through a constant λ. See the text and Garrett (2011) progressively decoupled from energy consumption and CO2 tually physically possible: political will can only go as far for details.emissions through gains in energy efficiency. Several of the as physical laws allow. The argument that will be presented widely used IPCC SRES scenarios even go so far as to allow is that, unfortunately, wealth cannot be decoupled from re- economic growth to continue while CO2 emissions stabilize source consumption. In fact, at least at the global scales that or decline (Raupach et al., 2007). are relevant to CO2 emissions, it appears that “Jevons’ Para- This “have our cake and eat it too” viewpoint has been dis- dox” does indeed apply: efficiency gains will backfire. For puted by many ecological economists. The argument against this reason, it is likely that all SRES scenarios considerably decoupling is that consumption29 of energy is thermodynam- overestimate the extent of economic health that is possible ically required for any system