What is Climate Justice?

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Climate change is threatening the basis for sustained human life on earth.

While often perceived as a matter of natural science (climate science) or politics (climate summits), its ethical aspects, especially in relation with considerations of justice, are often overlooked.

This is the starting point for this introduction to Climate Justice - click through the following pages to learn more about this concept!
While subject to annual fluctuations, global temperature records show a marked increase over the last decades.
This diagram shows the development of averaged annual near surface temperatures. Temperature anomalies are based on the HadCRUT4 land-sea dataset as published by the Met Office Hadley Centre .
Temperature anomalies are given in degrees celcius relative to the average temperature over the period 1961-1990. The median temperature anomaly, as well as the upper and lower bound anomalies (with a 95% confidence interval) are provided.
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This increase in temperature is caused by human greenhouse gas emissions, which rise steadily since the beginning of the industrial revolution. In the 20th century, this development dramatically accelerated.
Data from the Global Carbon Atlas. Displayed are only emissions of carbon dioxide (no other greenhouse gases included).
Emissions are attributed to the country / continent in which they physically occur.
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The consequences of climate change for our living conditions are not always but mostly negative.

Besides an increased occurrence of extreme weather events such as heat waves or hurricanes, rising sea levels pose a threat to coastal cities.
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If we want to avoid these consequences, we have to limit climate change, and therefore also global emissions. Current policies and national targets, however, are currently not sufficient to achieve this.
Data source: Climate Action Tracker. Note that emissions are expressed in Gt CO2 equivalents instead of Gt CO2 (unlike in other charts).
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Who is responsible for climate change? Looking at the figures, it becomes clear that greenhouse gas emissions are unequally distributed, and that the continents' shares change over time. Can we say that this distribution is unfair or unjust?
Data from the Global Carbon Atlas. Displayed are only emissions of carbon dioxide (no other greenhouse gases included).
Emissions are attributed to the country / continent in which they physically occur.
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We have to look at the per capita emissions to judge the situation.

We can see that, while Asia's (mainly China's) emissions are on the rise, its per capita emissions are still lower than those of countries such as Saudi Arabia or the United States of America.

We may have reasons to question the justice of this situation - why should somebody (prima facie) have more rights to emit than somebody else?
Data from the Global Carbon Atlas. Displayed are only emissions of carbon dioxide (no other greenhouse gases included).
Emissions are attributed to the country / continent in which they physically occur.
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The situation gets more complicated when we look at past emissions : Should we take historical emissions into account when judging the justice of the present situation?

(Press "Play" to see how the situation evolved.)

The "Polluter Pays Principle" is a central concept in the European environmental policy - according to this principle, those responsible for an environmental damage are primarily liable for its remediation. Taking this principle into account, one could argue for an inclusion of past emissions (which are the cause of today's environmental damages).

Data from the Global Carbon Atlas. Displayed are only emissions of carbon dioxide (no other greenhouse gases included).
Emissions are attributed to the country / continent in which they physically occur.
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There seems to be a relation between a country's per capita emissions and its affluence (as measured in terms of Gross Domestic Product).

This makes clear that allocating emission budgets means also allocating affluence and chances.

Note that both scales are logarithmic.

Data from the Global Carbon Atlas. Displayed are only emissions of carbon dioxide (no other greenhouse gases included).
Emissions are attributed to the country / continent in which they physically occur.
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What is there to distribute? Climate science tells us that there is a limited budget of greenhouse gas emissions which must not be exceeded if the worst consequences of climate change should be avoided.

How many degrees of warming we aim at is a political question. And how the remaining budget is to be distributed is a question of Climate Justice.
Every budget is associated with a probability of achieving the warming target. These probabilities are determined by the IPCC and reflect current uncertainties regarding the future develoment of the climate.

Example: If we aim at an overall global warming of 1.5°C, and want to achieve this target with a probability of 66%, we still could 420 Gt of carbon dioxide at the beginning of 2018. Under constant global 2018 emissions, this budget would be used up after about 12 years.

'Years left' are calculated under the assumption of constant global carbon dioxide emissions. Budgets refer to 1.1.2018.
Emission budget data from IPCC' Special Report on Global Warming of 1.5°C (2018), available at https://www.ipcc.ch/sr15 (budgets are displayed in chapter 2, table 2.2).
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Time to make some choices:

1. Based on what should future emissions be distributed?


2. Should historical emissions be taken into account?
Countries displayed here were exemplarily chosen and represent industrialized (United States), newly industrialized (Mexico) and developing (Botswana) countries.
Convergence & Contraction: Approach developed by the Global Commons Institute . Main assumption is that countries' per capita emissions converge in a (freely selecable) convergence year.
Budget Approach: Developed by WBGU . The global emissions budget is allocated on a per capita basis for all states.
Grandfathering Approach: The budget is allocated to states proportionally to their base year emissions. This approach is more or less implicitly adopted in most climate negotiations.
Besides the approaches displayed here, several other approaches exist, e.g. the Regensburg Model (Sargl et al.) or the Extended Smooth Pathway Model (Raupach et al.). Approaches displayed here were exemplarily chosen
In contrast to the other approaches, "Convergence and Contraction" relies not only on an emission budget, but also on assumptions about future global emission paths. For the sake of example and simplicity, a constant linear reduction of global emissions to zero is assumed, which is otherwise not realistic. A linear transition from grandfathering to per capita emissions is assumed.
Data from the Global Carbon Atlas.
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Depending on our understanding of justice, the depletion year of a state's budget varies.
Assumption: Country emissions remain constant at level of the selected base year. Note that selection of an earlier base year leads to cases where the budget is already depleted for some (mainly industrialized countries).
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Play a bit around to see how much budget would be left when we start allocation in different years!
Assumption: Country emissions remain constant at level of the selected base year. Note that selection of an earlier base year leads to cases where the budget is already depleted for some (mainly industrialized countries).
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While some countries already overused their budget, other countries still have plenty left - depending on our understanding of justice and the approach we choose.
Assumption: Country emissions remain constant at level of the selected base year.
If all countries have the same percentage of budget left (e.g. when 2018 is selected as base year), the alphabetically first 20 countries are displayed.
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Depending on our understanding of justice, a state's budget can vary drastically. Whatever this decision looks like, it will have profound consequences for some states and its citizens.

How much emissions we still can emit is a question of natural science.

Which global warming target we want to achieve is a political question.

How the remaining emission budget should be allocated is a question of Climate Justice.
Daniel Wiegand works as a CSR consultant and data scientist. Currently he is doing his doctorate in business ethics at the university of philosophy in Munich.

For more information, refer to my Personal website.

All code to create this website is available on my GitHub page.

For comments and suggestions contact me on climate-justice@posteo.de.