Reference values to NDCs resp. NDC calculators

Short introduction

Core question: 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 including tools are presented that involve distributing a global budget and determining national paths::

Tools based on the Regensburg Model Scenario Types are also offered

With these tools, we make a contribution to operationalizing the goals of the Paris Agreement.

In addition, resource sharing models are compared.

Basic idea behind the Regensburg Model Scenario Types RM 1 - 6 (here is a mathematical description)

With the help of the Regensburg Model Scenario Types, global or national emission paths can be determined that meet a given budget. The scenario types differ in the assumption about the property of the annual reductions. The emission paths are therefore indirectly determined essentially via the annual reductions. This approach is particularly useful when it comes to making political decisions about emission paths.

Basic idea behind the Regensburg Model (RM)

  1. Global paths: Global emission paths are determined that are compatible with a global CO2 budget to be specified. For this purpose, the RM tool provides the Regensburg Model Scenario Types RM 1 - 6 (see above).
  2. National paths: National emission paths are derived from this global paths with the Regensburg Formula, which leads to the convergence of per capita emissions.

Basic idea behind the Extended Smooth Pathway Model (ESPM; inspired by Raupach et al.)

  1. National budgets: A predefined global CO2 budget is distributed to countries. The ESPM tool offers the use of a weighted distribution key that includes the 'population' and the 'emissions' in a base year (here: 2019).
  2. National paths: The ESPM tool offers the Regensburg Model Scenario Types RM 1 - 6 (see above) to derive plausible national paths that adhere to a national budget.

Download tools and papers

National reference vlaues that are compatible with a given global CO2 budget 2018 - 2100

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.

Determine paths that meet a given budget

With this simple tool, with the help of the Regensburg Model Scenario Types (RM 1 - 6), global or national emission paths can be derived that meet a specified budget 2020 - 2100. This tool is particularly suitable if a global or national budget is already known and the first interest is in compatible emission paths or if the focus is on getting to know the RM Scenario Types.

Results of the tools based on the framework data specified by you

There is the option of making the results of the tools available as PDFs based on the framework data you specified.

Here you can download a form for a request Download.

Comparison similar approaches (Resource Sharing Models)

Resource sharing models directly address the allocation of a remaining global budget. This article will therefore give an overview of the properties of resource sharing models that, in principle, use current emissions and population as a distribution key. The following models are compared: Regensburg Model (Regensburg Formula), Contraction & Convergence (C&C), Smooth Pathway Models (Smooth Pathway Formula from Raupach and Extended Smooth Pathway Model), 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 self-integration. Please contact us: (mail to).

Mathematical papers

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