This paper provides a historical overview of the issue of equity and fair allocation in climate negotiations. The author addresses questions related to sharing of carbon space between countries and/or efforts to stay within it, in the context of sustainable development. Different allocation mechanisms are reviewed along with taking responsibility for climate change, capability to engage in abating it and potential for future contribution. The paper argues that apart from action by developed countries, mitigation will also be required to take place in developing countries and that this will require the flow of substantial support to developing countries. 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, the author argues. Furthermore, concerns related to equity as well as sustainability must be incorporated and integrated into coherent transitory strategies. The paper concludes that if global emissions are to stay within the carbon space consistent with the 2 degrees Celsius target, then developed economies should respond quickly and deeply in the form of mitigation action.