Cumulative Carbon and Just Allocation of the Global Carbon Commons
Pierrehumbert, R. T., Chicago Journal of International Law
Recent research has shown that the effect of human activities on climate can be characterised by a single statistic, called cumulative carbon. This statistic is the aggregate amount of carbon emitted in the form of carbon dioxide by activities such as fossil fuel burning and deforestation over the entire time such activities persist. In this paper, the concept is used to address the question of fair allocation of carbon emissions amongst nations or other emitting units. It is concluded that even if emissions prior to the year 2000 are left out of the accounting, North America would have a just obligation to cease emissions completely in thirteen years, even if the emissions rate were frozen at its current level. China, India, and other developing nations could continue emissions for much longer before exhausting their fair share of the Carbon Commons. If historical emissions are fully taken into account, North America exceeded its fair share of usage in 1970, and has been in carbon overdraft ever since, whereas none of the major nations of the developing world have yet exceeded their fair shares. It is concluded that, based on principles of human equality, North America, and in particular the US, has a strong moral obligation to take the lead in actions that will ultimately reduce global carbon emissions. Western Europe has similar obligations, but has begun measures to take on a fair share of responsibility for emissions reduction, whereas such action has been largely absent in North America.
Table of Contents
I. Introduction .................. 528
IL The Global Carbon Commons .................. 528
III. Principles For Just Allocation of the Carbon Commons .................. 537
IV. Discussion and Conclusions .................. 544
In the climate problem, there is a clear goal for a theory of justice: first to reduce the growth rate of global carbon dioxide emissions, and ultimately to bring them to zero before they commit the Earth to an unacceptable degree of climate disruption. We are not interested in abstract notions of who may deserve to be punished. There is a job to be done and, while finding a just solution is only a part of the process, it probably does play some role in persuading all parties to act in their mutual interest. Nations will rarely do anything that goes much against perceived self-interest just because it is the right thing to do, but on the other hand, in the absence of military coercion, nations will mightily avoid agreeing to restrictions they perceive (rightly or wrongly) as unjust.
Finding a solution to the threat of global climate change involves distribution of a valuable and scarce resource, the global Carbon Commons. It engages issues of equity between rich and poor (both within nations and across national boundaries), and between present and future generations. We also need to find principles for dealing with past emissions, in order to determine how much of the commons has been "used up," and how the unused portion of the commons should be allocated. These are quintessentially ethical problems. First, we need to clarify the nature of the resource being distributed.
II. THE GLOBAL CARBON COMMONS
When carbon is emitted into the air in the form of carbon dioxide (generally as a result of burning fossil fuels or as a consequence of deforestation), over time it is repartitioned among the atmosphere, the ocean, and the near-surface materials of the land. That portion that remains in the atmosphere causes global warming and other forms of climate disruption, while that portion that enters the ocean causes ocean acidification. Allocation of the global Carbon Commons requires us to know the relation between climaterelevant emissions and climate change.
Other significant greenhouse gases - notably methane - also contribute to global warming, but these do not merit consideration on an equal footing with C02 because their persistence in the atmosphere is so short. …