 To sum up, then, if we consider who has what responsibilities to address climate change, it is helpful to distinguish between four questions. First, who should engage in mitigation and adaptation? Second, who should bear any cost involved in mitigation and adaptation? Third, who has the responsibility to ensure that the relevant duty bearers for questions 1 and 2 discharge their responsibilities? Finally, for each of the above we need to know “what kind of agent is being ascribed duties?”