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).
With the help of the Regensburg Model Scenario Types, different courses can be mapped that adhere to a predefined budget:
We currently offer a total of six scenario types that cover the range of plausible options well. Here you will find a comprehensive mathematical description of the different RM Scenario Types and here a brief description.
The EDGAR database used here contains the CO2 emissions for all countries in the world due to the use of fossil fuels (excluding international shipping and aviation; ISA) and cement production. The following national CO2 budgets are therefore also without LUC and ISA.
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. Here is more background information.
For the ISA emissions, 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 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.
The actual emissions in 2020 and in 2021 are included in the emission paths.
global CO2 budgets 2020 - 2100 |
results for the largest emitters |
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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 |
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700 Gt |
global CO2 budgets
2020 - 2100 |
results for the largest emitters |
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---|---|---|---|---|
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 |
||||
700 Gt |
global CO2 budgets
2020 - 2100 |
results for the largest emitters |
|||
---|---|---|---|---|
Scenario Type
|
RM-3-lin |
RM-4-quadr |
RM-5-rad |
RM-6-abs |
400 Gt |
||||
550 Gt |
||||
650 Gt |
||||
700 Gt |
global CO2 budgets
2020 - 2100 |
results for the largest emitters |
|||
---|---|---|---|---|
Scenario Type
|
RM-3-lin |
RM-4-quadr |
RM-5-rad |
RM-6-abs |
400 Gt |
||||
550 Gt |
||||
650 Gt |
||||
700 Gt |
global CO2 budgets
2020 - 2100 |
results for the largest emitters |
|||
---|---|---|---|---|
Scenario Type
|
RM-3-lin |
RM-4-quadr |
RM-5-rad |
RM-6-abs |
400 Gt |
||||
550 Gt |
||||
650 Gt |
||||
700 Gt |
global CO2 budgets
2020 - 2100 |
results for the largest emitters |
|||
---|---|---|---|---|
Scenario Type
|
RM-3-lin |
RM-4-quadr |
RM-5-rad |
RM-6-abs |
400 Gt |
||||
550 Gt |
||||
650 Gt |
||||
700 Gt |
global CO2 budgets
2020 - 2100 |
results for the largest emitters |
|||
---|---|---|---|---|
Scenario Type
|
RM-3-lin |
RM-4-quadr |
RM-5-rad |
RM-6-abs |
400 Gt |
||||
550 Gt |
||||
650 Gt |
||||
700 Gt |
In the scenario types RM-3 and RM-4, the actual value from 2019 (indicated next to the country in the legend) was specified as the starting change rate for 2020. In scenario type RM-6, no start rate of change can be specified. The actual values for the years 2020 and 2021 have been included in the emission paths. In practice, of course, not all countries would need to choose the same scenario type.
If China does not reduce its emissions by 2030, there will be a huge gap that others cannot easily make up. We need a discourse on how we want to deal with this fact.
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: 'grandfathering'), all countries would have the same requirement to reduce their emissions by 2030 compared to 2019. The slightly different values in the graph when weighting the population with 0% are due to the consideration of actual emissions after 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.
We need to address the question of what framework data will lead to feasible national targets.
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 |
weighting
population key |
overview of
EU27 results |
400 Gt
|
50%
|
|
550 Gt |
||
650 Gt
|
100% |
EU28 |
Germany |
|
580 Gt |
||
800 Gt SRU: Maximum global budget that is still compatible with keeping a global temperature rise this century well below 2°C |
Here you can query the results for a country via a Google form based on the framework data that you specify; here is a request as a PDF.