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Allocating negative emissions to countries

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An advantage of the carbon budget is the ability to transparently share emissions to countries, for the purpose of comparability. Negative emissions makes that harder, and in this presentation we explore ways to allocate negative emissions to countries.

Published in: Environment
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Allocating negative emissions to countries

  1. 1. Allocating negative emissions to countries Glen Peters, Robbie Andrew (CICERO) Oliver Geden (SWP, MPI-M), Detlef van Vuuren (PBL, Uni Utrecht) Negative CO2 Emissions (22-24/05/2018, Gothenburg)
  2. 2. • One nice feature of carbon budget approaches is to “allocate” the budget to countries – Allocation is useful for comparing, not prescribing! • Negative emissions make allocation more difficult • Simple and transparent approaches can play an important niche and help users to understand mechanisms Background
  3. 3. Source: Robbie Andrew Simple approach, easy communication
  4. 4. We earlier allocated a carbon budget to countries to compare if their emission pledges were fair and ambitious We did not allow net-negative emissions, which greatly restricted the applicability of the method Source: Peters et al 2015; Global Carbon Budget 2016 A fair and ambitious agreement
  5. 5. Allocating negative emissions
  6. 6. Global CO2 emissions (fossil fuels, industry, & land-use change) in a “well below 2°C” scenario from MESSAGE It is possible to split the net emissions (black line) into gross positive and gross negative emissions. Source: Rockström et al (2017) Gross versus net emission pathways
  7. 7. It is then possible to derive a carbon budget for gross positive and gross negative emissions. The gross positive and negative budgets are always monotonically increasing / decreasing making “sharing” easier. Source: Rockström et al (2017) Gross versus net emission pathways
  8. 8. The gross positive and negative budgets can be distributed over time with stylized functions Positive: exponential decay with inertia based on current growth rate; Negative: S-curve (cosine) Source: Rockström et al (2017); own calculations Gross versus net emission pathways
  9. 9. The same function fit results from the IMAGE model, but IMAGE has a more rapid deployment of negative emissions Source: van Vuuren et al (2018); own calculations Gross versus net emission pathways
  10. 10. An advantage of stylized functions is the ability to quickly experiment with different configurations Here, pathways with different levels of CO2 removal show how CO2 removal reduces short-term mitigation rates Source: own calculations Gross versus net emission pathways
  11. 11. Distributing positive & negative emissions
  12. 12. • Allocate budget first, allocate pathway second • Point is not to discuss ethics, but to test the method • We use two methods of allocation – Current population (per capita) – Current emissions (grand fathering) • Other options will be included later – Positives: Historical responsibility, wealth, capacity, etc… – Negatives: bioenergy potential, CCS availability, etc… Allocating to countries
  13. 13. • We allocate positive and negatives asymmetrically – If positives by population, then negative by emissions – If positives by emissions, then negative by population • Low per capita emissions – Larger positive quota, smaller negative quota • High per capita emissions – Smaller positive quota, larger negative quota • Overly stylized, will be improved later Allocating positives & negatives
  14. 14. Blue: range of emission pathways with no net negative emissions; Grey: Range of positive emission pathways; Yellow: Range of negative emissions; Solid/Dotted: Net emission pathways China (high per capita emissions) Positives by population Negatives by emissions Positives by emissions Negatives by population
  15. 15. Blue: range of emission pathways with no net negative emissions; Grey: Range of positive emission pathways; Yellow: Range of negative emissions; Solid/Dotted: Net emission pathways USA (very high per capita emissions) Positives by population Negatives by emissions Positives by emissions Negatives by population
  16. 16. Blue: range of emission pathways with no net negative emissions; Grey: Range of positive emission pathways; Yellow: Range of negative emissions; Solid/Dotted: Net emission pathways Europe (high per capita emissions) Positives by population Negatives by emissions Positives by emissions Negatives by population
  17. 17. Blue: range of emission pathways with no net negative emissions; Grey: Range of positive emission pathways; Yellow: Range of negative emissions; Solid/Dotted: Net emission pathways India (low per capita emissions) Positives by population Negatives by emissions Positives by emissions Negatives by population
  18. 18. Given the use of stylized pathways, the pathways compare reasonably with IAMs (IMAGE shown here) Parameter choices: country budget allocation (positive, negative), residual positive emissions, initial mitigation rate, … Source: van Vuuren et al (2018); own calculations Model comparisons
  19. 19. Why does the UK have a net-zero year after the global average? Methodological issue or reality? Factors: Allocation method, initial mitigation rate, stylized functions, etc. Can these be addressed? UK example
  20. 20. Summary
  21. 21. • Positive and negative carbon budgets used with stylized functions to approximate output of IAMs – Quick and flexible method to understand processes • Possible to share emissions using different methods and approximate expected behavior • Next steps – Broader range of methods to allocate carbon budgets – Broader comparison with other results Allocating emissions to countries
  22. 22. Peters_Glen cicero.oslo.no cicerosenterforklimaforskning glen.peters@cicero.oslo.no Glen Peters

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