Dangerous climate change poses a fundamental ethical challenge: What is the fairest way of mitigating climate change? Many policies have been proposed (and some adopted) to realize this - policies including mass electrification (and the use of electric vehicles), carbon taxes and emissions trading schemes, investment in clean energy, redesigning towns and cities, fossil fuel non-proliferation treaties, a major deployment of renewable energy (wind, solar, hydroelectric, biofuels), and nuclear energy. Such policies have distributive effects. They often create benefits (for example, clean air, green jobs, better health, energy security) but also in some cases costs and harms (greengrabbing, displacement, unemployment, stranded assets, threats to health). They can result in social conflicts (for example, over financial resources, land, water and critical minerals). Given this, we face the questions 'What is the fairest way of moving to a low carbon society? What is a just transition?' This module explores these fundamental ethical questions. It analyses how the burden of mitigating climate change should be distributed; who is duty bound to bring it about; what a just renewables policy would be; what role practical considerations about political feasibility should play in our theorizing; whether there is a trade off between effectively mitigating climate change and fairness; and whether the existing political architectures at the state, regional and global levels, can be improved to better realize climate justice.