Sustainable Development and a Dwindling Carbon Space

Curbing global warming by setting long term maxima for temperature rise or concentrations of greenhouse gases defines spaces within which further emissions of these gases are to remain (referred to here as ‘carbon spaces’). This paper addresses questions related to how to share between countries the carbon space and/or efforts to stay within it, in the perspective of sustainable development; different allocation mechanisms are reviewed, responding to criteria such as ‘responsibility’ for climate change, ‘capability’ to engage in abating it, and ‘potential’ or future contribution. The carbon space remaining at any time will depend on effective mitigation up till that time, and will condense if more stringent maxima are to be set; per capita this space becomes smaller with rising population. Sharing the carbon space in a fair way requires “convergence” of currently widely unequal per capita emissions. If the world is to stay within the carbon space consistent with <2° warming, then developed economies—the wealthiest sources of greenhouse gases should quickly and deeply engage in mitigation. Also, substantial mitigation is to take place in developing countries and that this will require substantial support to developing countries (financially, technologically). Changing development paths can make a major contribution to climate change mitigation; this requires changes in investment, production and consumption patterns. Green New Deals as proposed in the context of a widened response to the current economic crisis could become a first phase of a fundamental transition towards a decarbonised global economy worldwide. Concerns to do with equity as well as sustainability must be incorporated and integrated into coherent transitory strategies.