This report has been authored on request of Aurora in the context of Aurora’s systemic, human rights-based climate litigation against the Swedish state. This report’s purpose is to operationalise the legal obligation for states to contribute with their fair share of global mitigation measures required to limit global warming to 1.5 °C, and apply this operationalisation to Sweden, based on the best available evidence from climate science and the relevant scholarly literature. Specifically, it reviews and discusses the literature on equitable effort sharing and, based on that literature as well as Aurora’s instructions, calculates the fair share of Sweden for i) the remaining global carbon budget for keeping global warming below 1.5 °C with 67 and 83 percent probability and ii) the global effort required to limit global warming in 2100 to 1.5 °C with no or limited overshoot, with 67 and 83 percent probability. The results show that under all assessed fair share allocation approaches that are consistent with Aurora’s request, there is a very significant gap between Sweden’s fair share and Sweden’s current mitigation measures. In fact, this gap is so large that it far exceeds the mitigation that is possible within Sweden. Therefore, mitigation efforts consistent with these fair shares cannot simply be implemented in Sweden’s territory alone – and instead imply mitigation cooperation (including through finance) with other countries on a very substantial scale, because the difference between Sweden’s mitigation fair share and the most ambitious domestic mitigation has to be implemented in other countries with Sweden being responsible for ensuring that this mitigation takes place, including by providing finance and other means of cooperation and support.