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Reference values to the NDCs resp. NDCs calculators:
Regensburg Model and Extended Smooth Pathway Model
Short introduction
Distribution of a global CO2 budget
CO2 affect the climate for a long time. Therefore, remaining global CO2 budgets correspond to certain limits of global warming (more information here).
Which concrete global budget we want to orientate by 2100, however, must ultimately be decided politically on the basis of the current state of scientific knowledge.
Such a global budget raises the question of how it can be distributed amongst the countries in a fair and economically reasonable way. Such a distribution should be an important guidance of the ratchet up mechanism (ambition mechanism) of the Paris Agreement with Nationally Determined Contributions (NDCs).
Here two models are presented to calculate national paths and budgets that are compatible with a given global budget 2018  2100:
 the Regensburg Model and
 the Extended Smooth Pathway Model.
In addition, resource sharing models are compared and a tool for determining global paths is offered.
Basic idea behind the Regensburg Model (RM)
 Global paths: Global emission paths are determined that are compatible with a global CO2 budget to be specified. For this purpose, the 'Tool_RM' provides six scenario types (RM 1  6), which differ in their assumptions about the course of the annual reductions.
 National paths: National emission paths are derived from this global paths in the convergence period with the Regensburg Formula, which leads to the convergence of per capita emissions.
Latest publication on the Regensburg Model (further publications
here):
Journal "Climate Policy"
published online on 14 June 2016:
The Regensburg Model: reference values for the (I)NDCs based on converging per capita emissions
Basic idea behind the Extended Smooth Pathway Model (ESPM; inspired by Raupach et al.)
 National budgets: A predefined global CO2 budget is distributed to countries. The 'Tool_ESPM' offers the use of a weighted distribution key that includes the 'population' and the 'emissions' in a base year (here: 2019).
 National paths: The 'Tool_ESPM' offers the Regensburg Model scenario types RM 1  6 to derive plausible national paths from a national budget.
Notes on the
relationship between
ESPM and
RM:
Depending on the chosen global path and the chosen convergence level, there is an implicit weighting of the population in the resulting national budgets in the RM. The use of this implicit weighting as an explicit weighting in the ESPM leads to very similar results as in the RM, as this
overview of the results according to ESPM and RM shows for the largest emitters.
Download tools and papers
 Excel tools for calculating national reference vlaues derived from national emission paths that are compatible with a given global CO2 budget 2018  2100
 Regensburg Model (converging per capita emissions):
 Tool_RM.xlsm
 Preview of the tool in the browser here
 Instructions for the tool
 Contains six scenario types (RM 1  6) to determine global emission paths that are compatible with a given global budget 2020  2100 (see mathematical description below). It is also possible to enter a global path yourself.
 Exemplary results according to the Regensburg Model with different global budgets:
Lists of national emission budgets and
reference values for all countries according to the RM 
global CO2 budget 2018  2100 
420 Gt 
570 Gt 
680 Gt 



 Extended Smooth Pathway Model (national paths derived from a national remaining budget):
 Tool_ESPM.xlsm
 Preview of the tool in the browser here
 Instructions for the tool
 A weighted distribution key consisting of "population" and "emissions" in base year 2019 is provided to determine remaining national budgets from a global budget. The remaining national budget can also be specified freely.
 Contains six scenario types (RM 1  6) to determine national emission paths that are compatible with a given remaining national budget (see mathematical description below).
 Application of the ESPM to the EU objectives (in German)
 Exemplary results according to the ESPM with different weighting of the population and different global budgets:
Lists of national emission budgets for all countries and
reference values for the largest emitters according to the ESPM 

global CO2 budget 2018  2100 
420 Gt 
570 Gt 
680 Gt 
weighting
population 
50% 



15% 



 Comparative overview of the results in RM and ESPM
Overview results ESPM and RM for the largest emitters and different global budgets 

 Determine global paths that meet a given global budget
In determining plausible global emission paths, the challenge before which we aside is particularly evident. Therfore we have decoupled determining smooth global paths in a separate tool.
 Tool_global_paths.xlsm
 Preview of the tool in the browser here
 Instructions for the tool
 Contains six scenario types (RM 1  6) to determine global emission paths that are compatible with a given global budget 2020  2100. These differ on the assumption over the property of the annual reductions (see mathematical description below).
 Contains in addition the illustrative IPCC SR1.5 paths P1  P4 (LED, S1, S2, S5) for comparison. The comparison shows that the RM scenario types are well suited to politically discussing appropriate paths that adhere to a given budget.
 Comparison similar approaches (Resource Sharing Models):
The following models are compared: Regensburg Formula, Contraction & Convergence (C&C), Smooth Pathway Models, Chakravarty et al. (cap per capita emissions), Höhne et al.
(common but differentiated convergence; CDC)
 Remark on the tools
The Excel tools include macros. On request, the tools can be provided without macros and the macros as text or bas files for selfintegration.
 Mathematical Papers
 Resource Sharing Models  A Mathematical Description
This paper shines the spotlight on the mathematical formulae of resource sharing models. It contributes to greater transparency and comparability through a uniform mathematical representation, by showing generalisations and mergers as well as similarities and differences between currently used models. It also contains mathematical proofs for specified properties of the models.
In Chapter 2 we consider models with a limited convergence period, at the end of which global emissions are allocated to countries according to population only (C&C, LIMITS, Regensburg Formula, CDC). The Smooth Pathway Models in Chapter 3 calculates national paths starting from allocated remaining national budgets. The Emission Probability Model in Chapter 4 determines country specific emission density functions and caps the emissions of individuals.
 Mathematical Description of the Regensburg Model Scenario Types (RM 1  6)
The Regensburg Model Scenario Types are used to derive plausible emission paths that meet a certain budget.
More downloads of this website
 Own publications and discussion papers here
 Tausendundeine Möglichkeit Treibhausgase einzusparen hier
 Ziel  Mittel  Weg (Instrumentenvergleich auf einer Seite) hier