A probabilistic approach to exploring global dynamics Nicky Grigg, Fabio Boschetti, Markus Brede, John Finnigan CSIRO, Australia AIMES Open Science Conference, Edinburgh 11 May 2010

CSIRO. A probabilistic approach to exploring global dynamics What, how and why? What: Interactions: population, carbon emissions, economy How: Low dimensional dynamic model Rates estimated from probability distributions fitted to UN datasets Ensembles of model runs to capture uncertainty and variability Why: Trial probabilistic approach Qualitative insights, informed by quantitative dynamics

Model overview CSIRO. A probabilistic approach to exploring global dynamics Cumulative emissions Population GDP birth rate death rate energy use per capita GDP per capita intrinsic growth rate Peak temperature change carbon intensity of energy use Damage rate

State variables CSIRO. A probabilistic approach to exploring global dynamics Cumulative emissions Population GDP birth rate death rate energy use per capita GDP per capita intrinsic growth rate Peak temperature change carbon intensity of energy use Damage rate

Rates inferred from probability distributions CSIRO. A probabilistic approach to exploring global dynamics Cumulative emissions Population GDP birth rate death rate energy use per capita GDP per capita intrinsic growth rate Peak temperature change carbon intensity of energy use Damage rate

Derived quantities CSIRO. A probabilistic approach to exploring global dynamics Cumulative emissions Population GDP birth rate death rate energy use per capita GDP per capita intrinsic growth rate Peak temperature change carbon intensity of energy use Damage rate

Scenarios CSIRO. A probabilistic approach to exploring global dynamics Cumulative emissions Population GDP birth rate death rate energy use per capita GDP per capita intrinsic growth rate Peak temperature change carbon intensity of energy use Damage rate

Model overview CSIRO. A probabilistic approach to exploring global dynamics Cumulative emissions Population GDP birth rate death rate energy use per capita GDP per capita intrinsic growth rate Peak temperature change carbon intensity of energy use Damage rate

CSIRO. A probabilistic approach to exploring global dynamics Birth rate vs GDP per capita Data from and

CSIRO. A probabilistic approach to exploring global dynamics Birth rate vs GDP per capita

CSIRO. A probabilistic approach to exploring global dynamics Death rate vs GDP per capita Data from and

CSIRO. A probabilistic approach to exploring global dynamics Death rate vs GDP per capita

CSIRO. A probabilistic approach to exploring global dynamics Energy use per capita vs GDP per capita Data from and

CSIRO. A probabilistic approach to exploring global dynamics Energy use per capita vs GDP per capita

Modelled historical distributions: population CSIRO. A probabilistic approach to exploring global dynamics * World population

Modelled historical distributions: cumulative emissions CSIRO. A probabilistic approach to exploring global dynamics * World cumulative emissions

Modelled historical distributions: world GDP CSIRO. A probabilistic approach to exploring global dynamics * World GDP

Mitigation CSIRO. A probabilistic approach to exploring global dynamics

Climate damages Committed peak temperature change due to cumulative emissions: (Raupach et al, 2010)

Climate damages CSIRO. A probabilistic approach to exploring global dynamics Relationship between damage rate and T peak :

Climate damages CSIRO. A probabilistic approach to exploring global dynamics Relationship between damage rate and T peak :

Proportion of runs with T peak < 2˚C CSIRO. A probabilistic approach to exploring global dynamics Mitigation completed sooner Steeper onset of damages

Proportion of runs with T peak < 2˚C CSIRO. A probabilistic approach to exploring global dynamics Mitigation completed sooner Steeper onset of damages

CSIRO. A probabilistic approach to exploring global dynamics Proportion of runs with rising GDP per capita Gentler onset of damages Mitigation completed sooner

CSIRO. A probabilistic approach to exploring global dynamics Proportion of runs with rising GDP per capita Gentler onset of damages Mitigation completed sooner

CSIRO. A probabilistic approach to exploring global dynamics Proportion of runs with T peak < 2˚C AND rising GDP per capita Gentler onset of damages Mitigation completed sooner

Population <10 billion only CSIRO. A probabilistic approach to exploring global dynamics Gentler onset of damages Mitigation completed sooner

Max allowable energy use per capita CSIRO. A probabilistic approach to exploring global dynamics Gentler onset of damages Mitigation completed sooner Energy use per capita (kg oil equiv/person/yr)

CSIRO. A probabilistic approach to exploring global dynamics Energy use per capita vs GDP per capita Data from and

Conclusions Data-driven probabilistic approach: Uses more of the information inherent in datasets Allows propagation of variability and uncertainty Forward model to 2100 generates distributions of trajectories consistent with system evolving under realistic rates Probability distributions are more informative than single trajectories. Qualitative dynamics: Surfaces in mitigation-damage space: steep boundary between poverty trap and good life. Population-energy patterns within mitigation-damage scenario. Applicability more broadly Framework suitable for studying other systems in which environmental limits interact with population and economy. CSIRO. A probabilistic approach to exploring global dynamics

Contact Us Phone: or Web: Thank you CSIRO Land and Water Dr Nicky Grigg Phone:

Model assumptions Population (P): birth and death rates. Cumulative carbon dioxide emissions since1751 (E) population size energy use per capita carbon intensity of energy supply. GDP (A): Endogenous and population-related growth rates Climate feedback on GDP: Global peak temperature change is a function of cumulative carbon dioxide emissions. Temperature changes damage the economy. CSIRO. A probabilistic approach to exploring global dynamics

Model equations: population Population (P) births/year deaths/year k birth is the birth rate per capita (births/person/year) k death is the death rate per capita (births/person/year) Birth and death rates change over time and are a function of GDP per capita

CSIRO. A probabilistic approach to exploring global dynamics Model equations: cumulative emissions Cumulative emissions since 1751 (E) c is the carbon intensity of energy (gC/MJ) k energy is the rate of energy use per capita (MJ/person/year) P is the population Energy use per capita varies over time and is a function of GDP per capita. Carbon intensity per MJ changes over time as an exogenously prescribed mitigation trajectory

CSIRO. A probabilistic approach to exploring global dynamics Model equations: GDP Climate-related damage rate GDP (A) Population- related GDP growth rate Intrinsic GDP growth rate = 0 : no population impact on GDP growth = 1 : population impact on GDP growth rate