Transcript Can we provide thermodynamic constraints for the long

Can we provide thermodynamic
constraints for the long-term coupled
evolution of the economy and the
atmosphere?
Tim Garrett
University of Utah
CO2 Emissions
SRES Emissions Scenarios out to 2100
All scenarios are considered
equally probable
2100
Range of possible futures
depends as much on
societal trajectories as
climate physics
Atmospheric CO2 Perturbation (ppmv)
But historically, the problem looks tightly constrained…
R2=0.90
xkcd.com
Cullenward et al. 2011
Climatic Change
The atmosphere is an
open thermodynamic
system
sunlight
atmosphere
dissipation to space
Available potential
energy density
…so is the global
economy
fuel
civilization
dissipation to space
Available potential
energy density
A child grows because it dissipates less energy than it consumes
Energy efficient consumption is central to a positive feedback driving growth
Wealth is a fiscal measure of our
capacity to enable the
consumptive flow of primary
(potential) energy. This flow
enables all civilization activities.
fuel
GDP ($/yr)
civilization
dissipation to space
The convergence of energetic
and material flows is what we
fiscally quantify as the real GDP.
By growing civilization,
convergence grows our capacity
to consume by expanding
access to new energy
reservoirs. This is what we
implicitly value as economic
production or the GDP.
POSITIVE FEEDBACK
Power of
money constant
Current rate of energy
consumption
Wealth
Past world real GDP
• Energy consumption rate is global economic wealth
• Wealth is an accumulation of past real economic
production. The GDP is a convergence of flows.
• Key point:  is hypothesized to be a constant coefficient:
the power of money
• Hypothesis is testable and falsifiable
Hypothesis evaluation
Inflation-adjusted wealth is an
implicit measure of the rate of
energy consumption by
civilization
C = Global Wealth
a = Global energy consumption rate
a/C = Power per dollar
 = 9.7 ± 0.3 mW
per 1990 US dollar
IPCC: “Future greenhouse gas (GHG) emissions are the product of very
complex dynamic systems, determined by driving forces such as
demographic development, socio-economic development, and
technological change. Their future evolution is highly uncertain.”
non-SRES global CO2 Emissions Identity
Power of
money constant
Current rate of energy
consumption
Wealth
Past world real GDP
non-SRES global CO2 Emissions Identity
carbonization of energy supply
Emissions
Past real GDP
Energy consumption rates
wealth of civ.
• Without decarbonizing, emissions cannot be
reduced without destruction of global wealth
• Current wealth is tied to the past history of real
GDP, which cannot be destroyed
Hindcast initialized with
current state in 1985
Dashed: observations
Color: hindcasts
Initialization
Gross World Product
(trillions 1990 $/yr)
Carbon Dioxide Concentrations
CThERM Multi-decadal coupled hindcasts
Forecasts to 2100
No switch from fossil fuels
Civilization divergence
3.7 - 8.3 ºC
1.9 - 4.4 ºC
SRES Models get an
unphysically high GDP per
[CO2] because they assume
that energy consumption can
be decoupled from the
economy through efficiency
gains
Conclusions
• Civilization’s future is tied to its past consumption.
• Wealth, energy consumption and CO2 emissions are
coupled through a constant
• Energy efficiency gains accelerate growth of wealth
and CO2 emissions
• The negative feedback on emissions and wealth is
resource depletion and environmental disasters.
• Shouldn’t SRES models appeal foremost to physics
if they are to be coupled to GCMs?