Extended smooth Pathway Model (ESPM)

Exemplary Paris-compatible national CO2 budgets, paths and targets
in the ESPM with different framework data

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. Here are key statements of the IPCC on remaining CO2 budgets. Which concrete global budget we want to orientate, 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).

Basic idea behind the Extended Smooth Pathway Model (ESPM) - brief background

  1. National budgets: A predefined global CO2 budget is distributed to countries. The ESPM-Tools offers the use of a weighted distribution key which contains the "population" and the "emissions" in a base year.
  2. National paths: The ESPM tool offers the Regensburg Model Scenario Types RM 1 - 6 (brief description) to derive plausible national paths that adhere to a national budget.

The key framework data

The most important framework data to be decided politically are:

National reference values (targets) and CO2 budgets

Data base: EDGAR (without Land-use change)

Land-use change and international shipping/aviation CO2 emissions

Since the data base at country level for CO2 emissions from land use changes (LUC) is still very scarce, for the following results we are distributing a global budget without LUC emissions to countries. The global LUC budget until 2100 is assumed to be zero in the following reference values. This implies that in total net positive LUC emissions will be offset by net negative LUC emissions until 2100.

For the CO2 emissions from international shipping and aviation (ISA), 3% of the global budget is reserved in the following reference values. This roughly corresponds to their share of current global CO2 emissions. This value is also an input value in our tools.

The EDGAR database used here contains the CO2 emissions for all countries in the world due to the use of fossil fuels and cement production. The following national CO2 budgets are therefore also without LUC and ISA.

Here is more background information.

RM Scenario Types

The rate of change for the start year (here: 2020) is an input value in the ESPM in scenario types RM 2 - 5. For the automated determination of the reference values for the six countries with the highest emissions, the 2019 rate of change was used as the starting value. The value used is given in the PDFs.

In the formulas for 2021, a normalised value was used for 2020 due to the temporary corona effect. However, the actual emissions in 2020 are included in the respective emission paths.


Weighting population key: 100%

weighting population key: 100%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
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550 Gt
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650 Gt
Download
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700 Gt
Download
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Download

Weighting population key: 85%

weighting population key: 85%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
Download
Download
Download
Download
550 Gt
Download
Download
Download
Download
650 Gt
Download
Download
Download
Download
700 Gt
Download
Download
Download
Download

Weighting population key: 70%

weighting population key: 70%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
Download
Download
Download
Download
550 Gt
Download
Download
Download
Download
650 Gt
Download
Download
Download
Download
700 Gt
Download
Download
Download
Download

Weighting population key: 50%

weighting population key: 50%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
Download
Download
Download
Download
550 Gt
Download
Download
Download
Download
650 Gt
Download
Download
Download
Download
700 Gt
Download
Download
Download
Download

Weighting population key: 30%

weighting population key: 30%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
Download
Download
Download
Download
550 Gt
Download
Download
Download
Download
650 Gt
Download
Download
Download
Download
700 Gt
Download
Download
Download
Download

Weighting population key: 15%

weighting population key: 15%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
Download
Download
Download
Download
550 Gt
Download
Download
Download
Download
650 Gt
Download
Download
Download
Download
700 Gt
Download
Download
Download
Download

Weighting population key: 0%

weighting population key: 0%
global CO2 budgets
2020 - 2100 (IPCC AR6)
results for the largest emitters
Scenario Type
RM-3-lin
RM-4-quadr
RM-5-rad
RM-6-abs
400 Gt
Download
Download
Download
Download
550 Gt
Download
Download
Download
Download
650 Gt
Download
Download
Download
Download
700 Gt
Download
Download
Download
Download

Emission paths of the six largest emitters

Framework data (corresponding reference values Download):

Paris-compatible emission paths six largest emitters

Interpretation:

If China does not reduce its emissions by 2030, there will be a huge gap that others cannot easily make up.


Weighting population vs. targets 2030/2019 of the six largest emitters

Framework data:

Interpretation:

If the population were weighted at 0% (and thus here an exclusive distribution of the remaining global budget according to the shares of global emissions in 2019), all countries would have the same requirement to reduce their emissions by 2030 compared to 2019. If the population share is included in the distribution key, then countries with higher per capita emissions in 2019 than the global average will face higher ambition requirements and countries with below-average per capita emissions (in the chart: India) will have lower ambition requirements.


Data base: European Environment Agency (EEA)

A few selected results for the EU are calculated using our general tool for determining emission paths that meet a certain budget. The following reference values include LUC and ISA.

global CO2 budgets
2020 - 2100 (IPCC AR6)
weighting
population key
overview of
EU27 results
400 Gt
50%
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550 Gt
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650 Gt
100%
Download

Data base: German Advisory Council on the Environment / Sachverständigenrat für Umweltfragen (SRU)

Parameters environmental report 2020 of the SRU Download:

global CO2 budgets from 2018 on (IPCC SR1.5) Download
EU28
Germany
580 Gt
Download
Download
800 Gt
SRU: Maximum global budget that is still compatible with keeping a global temperature rise this century well below 2°C
Download
Download

 


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