A probabilistic approach to exploring global dynamics

1. 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

2. 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 CSIRO. A probabilistic approach to exploring global dynamics

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

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

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

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

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

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

9. Birth rate vs GDP per capita Data from http://unstats.un.org and http://data.un.org CSIRO. A probabilistic approach to exploring global dynamics

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

11. Death rate vs GDP per capita Data from http://unstats.un.org and http://data.un.org CSIRO. A probabilistic approach to exploring global dynamics

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

13. Energy use per capita vs GDP per capita Data from http://unstats.un.org and http://data.un.org CSIRO. A probabilistic approach to exploring global dynamics

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

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

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

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

18. Mitigation CSIRO. A probabilistic approach to exploring global dynamics

19. Climate damages Committed peak temperature change due to cumulative emissions: (Raupach et al, 2010) CSIRO. A probabilistic approach to exploring global dynamics

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

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

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

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

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

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

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

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

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

29. Energy use per capita vs GDP per capita Data from http://unstats.un.org and http://data.un.org CSIRO. A probabilistic approach to exploring global dynamics

30. 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

31. Contact Us Phone: 1300 363 400 or +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au Thank you CSIRO Land and Water Dr Nicky Grigg Phone: +61 2 6246 5569 Email: nicky.grigg@csiro.au

32. 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

33. Model equations: population Population (P) deaths/year births/year kbirthis the birth rate per capita (births/person/year) kdeath 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

34. Model equations: cumulative emissions Cumulative emissions since 1751 (E) c is the carbon intensity of energy (gC/MJ) kenergyis 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

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